Patent Application
20170002999
Embodiments of the present invention generally relate to light sources using a reflector that reflects light.
Incandescent lamps or light sources commonly provide an illumination pattern in all directions (“omni-directional”). In contrast, light-emitting diodes (LEDs) provide illumination in primarily one direction. Omni-directional LEDs refer to light source products whereby a plurality of LEDs are housed in a bulb or diffuser that may include a reflector, and the LEDs are arranged to provide an illumination pattern in many directions. However, the reflector in conventional omni-directional LEDs may result in a shadow and/or abrupt edge being visible on the housing, which may be undesirable.
Accordingly, the present inventors have recognized that a need exists for an improved, dependable omni-directional light emitting light source.
In one embodiment, a light source assembly includes an at least partially transparent or translucent housing; a base plate disposed within the housing, the base plate supporting a plurality of annularly arranged light-emitting units; and a reflector, coupled to the base plate, the reflector having a substantially-annular discontinuous surface, wherein an exterior surface of the reflector is operative to reflect light emitted from the light-emitting units.
In another embodiment a reflector for use in a light source includes a plurality of annular sections, wherein two adjacent annular sections are connected by one or more connectors, and each section is separated from an adjacent section by a gap, wherein the plurality of sections are operative to reflect light.
Aspects and/or features of the invention and many of their attendant benefits and/or advantages will become more readily apparent and appreciated by reference to the detailed description when taken in conjunction with the accompanying drawings, which drawings may not be drawn to scale.
Some embodiments may include a light source that includes a reflector having a discontinuous surface. In some embodiments, the reflector may include a plurality of ring-shaped sections with gaps between the sections. Light emitted from light emitting units may be reflected by a reflective ring-shaped surface, and may pass through the gaps between the sections. The combination of reflective surfaces and gaps may reduce the shadow produced by conventional omni-directional light products.
Another consideration addressed by one or more embodiments is energy efficiency. An international standard for energy efficient consumer products is Energy StarSM. Devices carrying the Energy Star mark, such as light sources, have met certain Energy Star requirements and may use 20-30% less energy than required by federal standards. Regarding Energy Star requirements for light sources, and in particular for ENERGY STAR Lamps V1.1, for an omni distribution luminous intensity (candelas (cd)) may be measured within each vertical plane at a 5° vertical angle increment (maximum) from 0° to 135°. The measurements may be repeated in the vertical planes about the lamp (polar) axis in maximum increments of 22.5°, from 0° to 180°. In particular, to qualify for an Energy Star rating, lamp luminous intensity distribution may emulate that of a reference incandescent lamp as follows: 90% of the luminous intensity measured values (candelas) shall vary by no more than 25% from the average of all measured values in all planes; all measured values (candelas) shall vary by no more than 50% from the average of all measured values. Additionally, the light distribution zone may be vertically axially asymmetrical, where at least 5% of the flux (lumens) may be emitted in the 135° to 180° zone, as illustrated by the omni-directional light source 100 in
To meet Energy Star requirements, conventional omni-directional LEDs typically include a particular ratio of LEDs positioned central to a reflector and around an exterior of the reflector. While some conventional omni-directional LEDs have not included centrally positioned LEDs, to reduce LED counts and thereby reduce costs, for example, the shadow in these light sources may increase and optical efficiency may decrease compared to conventional omni-directional LEDs including interior and exterior LEDs.
The housing 202 may be coupled to a lamp base 212. The housing 202 may have an A-line shape, such as that depicted in
The lamp base 212 may include the base plate 208. While the base plate 208 shown herein is substantially circular-shaped, any other suitable shape may be used. When assembled, the base plate 208 is positioned within the housing 202 of the light source 200. The base plate 208 may be one of coupled to the lamp base 212 (e.g., via a mounting hole (not shown) engageable with a screw or fastener, for example) and integrally formed with the lamp base 212. The base plate 208 may include a central hole 211 that may provide a path for wires to connect a driver to the light emitting units 206, or may provide a space for push-in connectors that may mount to a circuit board. The base plate 208 may include a top surface 218 and bottom surface 220 that are planar and parallel to each other. In one or more embodiments, the plurality of light emitting units 206 may be mounted to the top surface 218 of the base plate 208. The base plate 208 may be a circuit board connected electrically to the light emitting units 206 to provide power to the light emitting units 206. The light emitting units 206 may be light-emitting diodes (LEDs) or any other suitable light source. In one or more embodiments, the light emitting units 206 may be annularly arranged around the base plate 208. In one or more embodiments, the base plate 208 may include a base plate opening 224 that may correspond with a lamp base opening 226. While the base plate opening 224 and lamp base opening 226 are annularly shaped, as shown in
The reflector 204 may include a reflector base 228. As shown in
The reflector 204 may include an interior surface 232 and an exterior surface 234. The interior 232 and exterior 234 surfaces may be reflective and may be made from the same or different materials. In one or more embodiments, the reflector 204 may be made from a reflective material or may be coated with a reflective material. In one or more embodiments, the reflector 204 may be mounted to the base plate 208 such that the light emitting units 206 are arranged circumferentially between an exterior surface 234 of the reflector 204 and an edge 235 of the base plate 208. In one or more embodiments, an arrangement of light emitting units 206 on the base plate 208 within the interior surface 232 of the reflector 204 may be avoided to provide for more efficient thermal usage and reduced heatsink designs, while the reflector 204 provides a reduced shadow compared to conventional omni-directional light sources, as further described below. While the reflector 204 shown herein may be substantially funnel- or annularly-shaped, having a cross-section that gradually decreases in a direction towards the reflector base 228, any suitable shaped reflector may be used.
In one or more embodiments, the reflector 204 may be discontinuous and include a bottom section 236 and one or more upper sections 238, whereby each adjacent section 236, 238 is separated by at least one gap 240. As described further below, the discontinuous aspect of the reflector 204 (e.g., split into two or more sections) may allow precisely targeted or directed light to pass through the gap(s) in the reflector 204. Of note, the precisely targeted light may reduce and/or eliminate the abrupt shadow edge provided with conventional omni-directional LEDs. Additionally, by precisely targeting the light, Energy Star requirements may be met for a variety of light emitting unit distributions, including a distribution with no centrally located light emitting unit. In one or more embodiments, a gap width may be 5% to 20% of the overall height of the reflector 204, but other suitable gap widths may be used. In one or more embodiments, the gap width may be approximately 12% of the overall height of the reflector 204. In one or more embodiments, the gap width may be based on the placement of the light emitting units 206 relative to the exterior surface 234 of the reflector 204. For example, as the distance between the light emitting units 206 and the exterior surface 234 of the reflector 204 increases, the size of the gap may increase such that a suitable amount of light may be precisely targeted to meet Energy Star requirements, for example. In one or more embodiments, the reflector 204 may be formed as a single article and the sections 236, 238 may be formed by removing at least a portion of the reflector 204, such that the sections 236 may be connected to each other via one or more connectors 239, (e.g., the remaining portion of the reflector) integrally formed with the reflector 204. In other embodiments, the sections 236 and 238 may be separately formed and coupled together by one or more connectors 239. The bottom section 236 may be integrally formed with the reflector base 228. In one or more embodiments, the exterior surface of the bottom section 236 may be perpendicular to the top surface 218 of the base plate 208. In one or more embodiments, the exterior surface of the bottom section 236 may be curved. In one or more embodiments, the exterior surface 234 of the upper section 238 may be curved or arc-shaped. In one or more embodiments, the curve of the upper section 238 may extend outward from a bottom edge 242 of the upper section 238 towards a top edge 244 of the upper section 238 such that a circumference of the top edge 244 is greater than a circumference of the bottom edge 242. In one or more embodiments, the curve of the upper section 238 may be such that the top edge 244 of the upper section 238 is vertically aligned with at least one of the base plate edge 235 and an outer edge 246 of the light emitting unit 206 positioned closest to the base plate edge 235, such that at least a portion of the upper section 238 is located over the light emitting unit 206. In one or more embodiments, a point on an outer edge 246 of a light emitting unit 206 is positioned in a plane which is substantially perpendicular to the base plate 208, and wherein at least one section of the reflector 204 intersects that plane.
In operation, as the plurality of light emitting units 206 emit light in substantially the same direction, the reflector 204 guides the light emitted by the light emitting units 206, as indicated by the light traveling paths in
The above descriptions and/or the accompanying drawings are not meant to imply a fixed order or sequence of steps for any process referred to herein; rather any process may be performed in any order that is practicable, including but not limited to simultaneous performance of steps indicated as sequential.
Although the present invention has been described in connection with specific exemplary embodiments, it should be understood that various changes, substitutions, and alterations apparent to those skilled in the art can be made to the disclosed embodiments without departing from the spirit and scope of the invention as set forth in the appended claims.
