The present disclosure is related to an LED light system, and more particularly, to an optical assembly to control a light pattern of a light beam for a spot or narrow flood LED-type light system.
Traditional light sources include incandescent, high-intensity discharge (HID), and compact-fluorescent (CFL) light sources, all of which emit light in all directions (i.e., non-directional light beam). To direct the non-directional light beam down from and out of a recessed fixture, lighting manufacturers have traditionally designed reflectors using a parabolic shape, which is intended to focus the non-directional light beam toward an illuminated target (e.g., a floor or wall surface). Rapid advancements in light-emitting diode (“LED”) technology have caused manufacturers to replace the traditional light sources with LED light sources, which are inherently directional light sources. The manufacturers have continued using traditional reflectors (e.g., parabolic-shaped reflectors) to minimize glare; however, LED light sources are inherently less diffuse emitters than these traditional light sources resulting in additional lighting designs concerns. For example, the combination of LED light sources with a traditional reflector may produce a light beam with a light pattern having a harsh edge between a center beam light area and a peripheral light area (surrounding the center beam light area) of the light beam, which is aesthetically unappealing in spot or narrow flood light applications.
In an LED light system of the spot or narrow flood variety, and especially for the interior lighting variety, it is desirable that the LED light system produces a light beam with a light pattern that provides a smooth or smoother transition, without harsh edges, between a center beam light area and a peripheral light area (surrounding the center beam light area) of the light beam. It is also desirable that the peripheral light area of the light beam is softened and blended into a surrounding darkness, while maintaining a center beam light area with a high Center Beam Candlepower. It is further desirable that this smooth transition be accomplished in a cost-efficient manner and preferably results in a broader area of illumination. To address these and other issues, an improved and cost-efficient optical assembly is provided for a LED light system, in which a light diffuser with a central opening is suspended inside of the reflector to redistribute light received from the LED light source. The light diffuser redistributes light to soften and broaden out the peripheral light area, thereby providing a smooth or smoother transition between the center beam and peripheral light areas of the light beam. At the same time, the central opening of the light diffuser allows light from the LED light source to pass directly therethrough to provide the center beam light area with a sufficiently high light intensity (e.g., a bright center beam with a high Center Beam Candlepower).
In accordance with an embodiment, the LED light system includes an LED light source, an optical assembly and an optic housing (e.g., a housing or mounting frame) to house the LED light source and the optical assembly. The optical assembly includes a conical reflector with a narrow open top and a wide open bottom, a light diffuser, an optic holder to suspend the light diffuser inside of the conical reflector, and an optical medium. The optic holder is mounted to the narrow open top of the reflector, and the optical medium is positioned over or across the wide open bottom of the reflector. The light diffuser has an annular shape with a central opening, and is formed of a light diffusing material to diffuse light received from the LED light source. The optic holder can be designed with a shape and a light-transmissive material (e.g., a light transmitting material) to maximize an overall light output efficiency of the LED light system.
The description of the various exemplary embodiments is explained in conjunction with the appended drawings, in which:
As an initial matter, it will be appreciated that the development of an actual, real commercial application incorporating aspects of the disclosed embodiments will require many implementation specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation specific decisions may include, and likely are not limited to, compliance with system related, business related, government related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time consuming in an absolute sense, such efforts would nevertheless be a routine undertaking for those of skill in this art having the benefit of this disclosure.
It should also be understood that the embodiments disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Thus, the use of a singular term, such as, but not limited to, “a” and the like, is not intended as limiting of the number of items. Similarly, any relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like, used in the written description are for clarity in specific reference to the drawings and are not intended to limit the scope of the invention.
Before describing the various exemplary embodiments in the present disclosure, a few terms are also discussed below for the explanatory purposes.
A “beam angle” defines the light pattern around the light beam's center out to the angle where the light (luminous) intensity is half that of the maximum luminous intensity.
A “Center Beam Candlepower” is the light intensity at the center of the light beam such as for a reflector-type light system.
A “field angle” is the angular dimension of a cone of light from a light system, which encompasses the central part of the light beam out to the angle where the light intensity is 10% of maximum. The field angle is useful in describing a light output of a light system, particularly where the light output begins to fade into the surrounding environment (e.g., darkness).
A “field light” is the light output of a light system over or across the field angle, or in other words, up until the light output has fallen to 10% of maximum light intensity.
Turning to the figures,
The optical assembly 100 includes a reflector 110 (also referred to as “primary optic”), a light diffuser 130 (also referred to as “secondary optic”) and an optical medium 160. The light diffuser 130 is suspended inside of the reflector 110 by an optic holder 140, and is configured with a predetermined size and shape and at a predetermined distance from the LED light source 30 to redistribute light, such as the field light. Specifically, the light diffuser 130 redistributes light to soften and broaden out the peripheral light area, and thus, to smooth out a transition between the center beam light area and the peripheral light area of the light beam. The use of the light diffuser 110 provides a simple, cost-efficient optical assembly, which does not require costly and complex optical components, such as additional reflectors, to provide a light beam with a light pattern having a smooth or smoother transition between the center beam light area and the peripheral light area. A detailed description of the various components of the optical assembly 100 will be described in greater detail below with reference to both
As shown in
The light diffuser 130 has an annular shape with a central opening 132 and a disk-shaped portion 134. The disk-shaped portion 134 is formed of a light diffusing material to diffuse light. The light diffusing material can include polycarbonate (e.g., polycarbonate film or lens), blasted glass, textured acrylic, volumetric diffuser, or any suitable material with light diffusing properties. The light diffuser 130 is suspended inside of the reflector 110 by the optic holder 140, which aligns the light diffuser 130 along an optical axis, in this example, a centerline of the optical assembly 100. The light diffuser 130 is used to control light distribution, such as of the field light, to reduce a harsh edge, and thus, to smoothen a transition between the center beam light area and the peripheral light area bordering and surrounding the center beam light area of the light beam produced by the LED light system 10. At the same time, the central opening 132 of the light diffuser 130 allows light from the LED light source 30 to pass directly therethrough to produce a light beam with the center beam light area having a sufficiently high light intensity (e.g., a bright center beam with a high Center Beam Candlepower).
The optic holder 140 includes an upper ring 142 with a central upper opening 150, a lower ring 144 with a central lower opening 152, and a plurality of spaced-apart supports 146 (e.g., vertical supports) connected between the upper and lower rings 142, 144. The optical holder 140 also includes a plurality of spaced-apart windows 154 (e.g., openings) to allow light, such as from a light source (e.g., the LED light source 30 in
As further shown in
To assemble the light diffuser 130 into the reflector 110, the light diffuser 130 is connected to the lower ring 144 of the optic holder 140 via the hooks 148. The lower ring 144 of the optic holder 140 is then inserted along with the light diffuser 130 through the top opening 120 of the narrow open top 112 of the reflector 110 until the upper ring 142 abuts against the narrow open top 120. Thereafter, the optic holder 140 is twisted until the tabs 124 of the reflector 110 engage corresponding slots 156 of the optic holder 140.
The optical medium 160 is arranged over or across the bottom opening 122 of the wide open bottom 114 of the reflector 110. In this example, the optical medium 160 has a circular shape, and has plurality of spaced-apart notches 162 along an edge of the medium. The optical medium 160 can be formed of a light diffusing material, such as glass or polycarbonate (e.g., a polycarbonate lens) which can have a light diffusing surface. The optical medium 160 can be used to further soften and enhance a continuity of the light pattern of the light beam produced by the LED light system 10.
The media cartridge 50 is provided to support and secure the components of the optical assembly 100 inside the cavity 22 of the optic housing 20. In this example, the media cartridge 50 has a body 270 with a cylindrical shape. The body 270 of the media cartridge 50 includes a top 272 and an opposite bottom 276. The top 272 includes a top opening 274 to receive the optical assembly 100. The bottom 276 includes a bottom opening 278 through which light is outputted. The media cartridge 50 also includes an interior rim 280 (e.g., a rim, lip or flange), a plurality of spaced-apart interior stops 282 and one or more exterior grooves 284. The interior rim 280 is used to support the optical medium 160 and the other components of the optical assembly 100. The interior stops 282 are parallel spaced-apart vertical protrusions, which are configured to engage respective notches 162 of the optical medium 160 and act as a guide when assembling the optical medium 160 into the media cartridge 50. The interior stops 282 prevent horizontal or lateral movement of the optical medium 160, when assembled onto the media cartridge 50. The interior stops 282 can also be used to receive spring clips (not shown), which can be connected to the optic housing 20 and help to guide and align the optical assembly 100 in the optic housing 20.
Once the optical assembly 100 is assembled onto the media cartridge 50, the media cartridge 50 can be inserted through an open end 26 (e.g., an open bottom) of the optic housing 20. The groove(s) 284 of the media cartridge 50 are aligned and engaged with corresponding tab(s) 24 of the optic housing 20 to secure the media cartridge 50, along with the optical assembly 100, to the optic housing 20 of the LED light system 10. As shown in
d1=H*tan(θ), and <1>
d2=H*tan(β), <2>
where d1 is a radius of the central opening of the light diffuser 130,
d2 is a radius of the light diffuser 110,
H is a height (e.g., distance or focal length) from the LED light source 30 to the light diffuser 130,
θ is an angle between a centerline from the LED light source 30 to the light diffuser and a line from a center of the LED light source 30 to a perimeter of the central opening 134, and
β is an angle between the centerline from the LED light source 30 to the light diffuser 130 and a line from a center of the LED light source 30 to a perimeter of the light diffuser 130.
The above-note relationship is provided as an example. It should be understood that the size, shape and position of the light diffuser 110 can be configured according to the characteristics of the LED light source and the reflector, such as the type, size, shape, position and output characteristics.
To evaluate the design of the optical assembly, such as in
As further shown in
It should be understood that the optical assembly 100, as described with reference to
Words of degree, such as “about”, “substantially”, and the like are used herein in the sense of “at, or nearly at, when given the manufacturing, design, and material tolerances inherent in the stated circumstances” and are used to prevent the unscrupulous infringer from unfairly taking advantage of the invention disclosure where exact or absolute figures and operational or structural relationships are stated as an aid to understanding the invention.
While particular embodiments and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the invention.
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http://www.khatod.com/khatod/view—products?KCLP1856CR—Reflectors—for—LUXEON—LEDs—Narrow—Beam,3875,1, Oct. 5, 2015. |
Number | Date | Country | |
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20170102126 A1 | Apr 2017 | US |