Patent Grant
9612002
Embodiments of the present invention generally relate to lighting and lighting devices. In particular, the present disclosure relates to embodiments of a lighting apparatus using light-emitting diodes (LEDs), wherein the embodiments exhibit a spectral power distribution with enhanced red-green color contrast and enhanced overall color preference. In certain embodiments, lamps described herein may pertain to A-line lamps (e.g., A19-type) or BR lamps (e.g., BR30-type).
Incandescent lamps (e.g., integral incandescent lamps and halogen lamps) mate with a lamp socket via a threaded base connector (sometimes referred to as an “Edison base” in the context of an incandescent light bulb). These lamps are often in the form of a unitary package, which includes components to operate from standard electrical power (e.g., 110 V and/or 220 V AC and/or 12 VDC). Such lamps find diverse applications such as in desk lamps, table lamps, decorative lamps, chandeliers, ceiling fixtures, and other general illumination applications. Several geometric shapes of incandescent lamps are used in such applications, including, but not limited to, A-line, R, BR, PAR, Decorative (Deco), and MR types of lamps.
Some types of incandescent lamps have an enhanced ability to render the red-green color contrast of illuminated objects. Such lamps have great appeal to users of lamps to illuminate objects, since they may cause the color of such objects to appear more rich or saturated. Especially appealing incandescent lamps of this type include the Reveal® brand of lamps which are sold by GE Lighting, an operating division of the General Electric Company. Customers of Reveal® products also prefer the “whiter” and “brighter” appearance of the light, and the enhanced overall color preference when compared to an unenhanced white spectrum.
Solid-state lighting technologies such as light-emitting diodes (LEDs) and LED-based devices often have superior performance when compared to incandescent lamps. This performance can be quantified by the useful lifetime of the lamp (e.g., its lumen maintenance and its reliability over time), lamp efficacy (lumens per watt), and other parameters.
It may be desirable to make and use an LED lighting apparatus also having appealing red-green color contrast properties.
Presented herein are LED based lamps. In an advantageous embodiment, an LED based lamp includes a concave optical diffuser, a separate concave neodymium-doped glass bulb, a reflector, a printed circuit board that includes a plurality of light-emitting diodes (LEDs) configured to emit light, and a heat sink body. The concave optical diffuser has a first interior volume, and the concave neodymium-doped glass bulb is positioned within the first interior volume. The neodymium-doped glass bulb defines a second interior volume, and both the reflector and the printed circuit board are positioned within the second interior volume. In some embodiments, the reflector includes a sloped annular wall with an inner reflective surface and an outer reflective surface, and a bottom portion of the reflector is connected to the printed circuit board. The heat sink is thermally connected to the printed circuit board and to the reflector.
In other beneficial embodiments, an LED based lamp is configured as a flood lamp, or BR-type lamp. In an implementation, an LED lamp includes an optical diffuser having a disc or concave disc shape, a heat sink body affixed to the optical diffuser, a reflector, a concave neodymium-doped glass bulb, and a printed circuit board comprising a plurality of LEDs. The heat sink body has a wall defining a first interior volume, and the reflector has a sloped annular reflective wall and is positioned within the first interior volume. The heat sink body has an interior surface defining a second interior volume, and the concave neodymium-doped glass bulb is positioned within the second interior volume. The printed circuit board is positioned at a lower portion of the reflector and is in thermal communication with the heat sink body. The plurality of LEDs on the printed circuit board is configured to emit light through the concave neodymium-doped glass bulb.
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.
In general, and for the purpose of introducing concepts of embodiments, described are LED-based lighting apparatus or lamps.
In some embodiments (for example, an A-line), the apparatus comprises an optical diffuser having a hemispheroidal, spheroidal, prolate or oblate ellipsoidal, ovoid, conical, polygonal-faced, or toroidal shape. The diffuser has a concave side defining a first interior volume. The apparatus further comprises a glass bulb having a hemispheroidal, spheroidal, prolate or oblate ellipsoidal, ovoid, conical, polygonal-faced, or toroidal shape, not necessarily the same shape as the optical diffuser, and doped with neodymium (Nd) oxide, Nd2O3, substantially nested within the first interior volume and generally separate from the optical diffuser. The bulb has a concave side which further defines a second interior volume. The apparatus includes a reflector, such as a truncated tapered reflector, i.e., generally having a shape of a truncated axisymmetric revolution of a conic section, and having an internal and external surface. In an implementation, the reflector has a sloped annular wall generally having a cross-section shape of a conic section. However, in some embodiments the sloped annular wall may be a straight wall or may be a curved wall. In some embodiments, the reflector also comprises a central transparent portion or central aperture defined by the interior of the reflector wall. The reflector is received substantially within the second interior volume.
In some embodiments, the lamp further comprises a plurality of LEDs mounted to a circuit board. The plurality of LEDs is configured to emit light generally axially upward, in a direction substantially perpendicular to the circuit board. Note that the apparatus is generally longitudinal, with a diffuser at an upper end and a base at a lower end. At least a first portion of the plurality of LEDs is configured to emit light through a central aperture of the reflector. In addition, at least a second portion of the plurality of LEDs is configured to emit light that reflects from a sloped annular reflective wall of the reflector.
The apparatus may further include a heat sink body which is in thermal communication with the circuit board, in order to dissipate the heat emanating from the plurality of LEDs when the apparatus is in operation. In the A-line embodiment, the heat sink body may include an annular groove at an upper portion thereof. The annular groove is sized and shaped to receive both a lip of the bulb and a lip of the diffuser therein.
The apparatus may further include a capper that has driver circuitry substantially enclosed within. The capper may be affixed to a lower portion of the heat sink. In some implementations, the apparatus includes a threaded base, to receive power from a socket.
In an A-line embodiment, the optical diffuser may be made of a glass or a polymeric material, e.g., a polycarbonate such as Teijin ML5206. The optical diffuser is usually capable of veiling light, such that light from individual LEDs is mixed and/or obscured. Generally, the diffuser distributes light and diffuses the light of individual LEDs. The optical diffuser may comprise a weakly diffusing low-optical-loss injection molded plastic bulk diffuser. In some embodiments, the optical diffuser generally has a white external appearance when the apparatus is not operation. The optical diffuser is generally separate from the neodymium-doped glass bulb and functions to diffuse light from the LEDs and to advantageously protect the neodymium-doped glass bulb from shattering or cracking from potentially damaging impacts that may occur (such as when or if the lamp is dropped onto a floor having a hard surface).
The glass bulbs in accordance with the embodiments disclosed herein may comprise a nominally soda lime glass, having impregnation with a neodymium compound such as neodymium oxide. The glass may comprise from about 2 wt % to about 15 wt % Nd2O3, for example, 6 wt %. Nd2O3. It is not preferred for the Nd2O3 to be impregnated into some polymer materials, in which the peak wavelength of the absorption may be shifted from that of the Nd-glass absorption which typically peaks at about 585 nm as shown in U.S. Published Patent Application No. 2007/0241657 A1, which is hereby incorporated by reference for all purposes. The peak wavelength and shape of the absorption spectrum depends on the material matrix into which the Nd2O3 is embedded, such that in some polymer embodiments, the peak absorption is so far away from the desired 585 nm, that the desired red-green enhancement is not obtained, or is not optimized. The glass bulb may also have an outer diameter of from about 50 to about 60 millimeters (mm) (for example, about 52 mm) and a wall thickness of from about 0.1 to about 2 mm (e.g., 0.5 mm). One function of the glass bulb is to absorb light from the LEDs when the apparatus is in operation, to induce a depression in a yellow portion of the visible light spectrum when light is transmitted therethrough. Of course, other types of glass or glass bulbs are possible, provided that such glass bulbs can modify a light source to induce a depression in a yellow portion of the visible light spectrum and increase red-green color contrast. In addition, other dimensions of the glass bulb are possible, as long as the glass bulb is in the optical path of some or all of the light emitted by the LEDs.
As aforementioned, in the A-line embodiment, the truncated conical reflector has a central aperture, and a first portion of the plurality of LEDs is configured to emit light rays axially through the central aperture. These light rays impinge directly onto the glass bulb and pass through to impinge on the optical diffuser. There is also a second portion of the plurality of LEDs which is arranged or configured to emit light so as to reflect from an external surface of the reflector, so as to distribute light in a radial direction and also in the direction of the base at the lower end of the apparatus. This combination of reflector and diffuser is effective to distribute light in a nearly omnidirectional manner. Generally, the reflector comprises a wider end and a narrow end, with the narrow end proximate the circuit board and with the wider end proximate the neodymium-doped glass bulb. A reflector in accordance with the several embodiments described herein may comprise a polymeric material and may be injection molded, although it may also be formed of metallic material in part or in whole. The external surface of the reflector may be a specular or a diffuse white, high reflectivity surface. Such a high reflectivity surface is usually achieved via highly reflective coatings and/or laminates.
In some embodiments, a heat sink body 406, 506 may be mated or otherwise affixed to the optical diffuser 404, 504. As shown in
In this example embodiment, the LED lamp 400, 500 may include a truncated reflector 403, 503 having a sloped annular reflective wall generally described by an axisymmetric revolution of a conic section, and a central aperture. The truncated reflector may generally have a shape of a truncated cone or parabola, or possibly a compound parabolic collector (CPC). This reflector may be received substantially within the first interior volume defined by the heat sink body 406, 506. An interior of the truncated reflector 403, 503 defines a second interior volume. The truncated reflector 403, 503 also may include a central transparent portion or central aperture on a forward end or top end thereof, to permit light emitted from a light engine (or light module including a plurality of LEDs) to impinge upon a Nd-doped glass dome 402, 502. The central aperture may be defined by the interior wall of the truncated reflector. In some embodiments, a reflector in accordance of this disclosure may be of a polymeric material and may be injection molded, but it could also be formed of a metallic material in part or in whole. In some implementations, the internal surface of the reflector 403, 503 comprises a diffusive high reflectivity surface. This diffusive high reflectivity surface may be achieved via highly reflective paints and/or laminates.
The LED based lighting apparatus 400, 500 may include a hemi-spheroidal-shaped neodymium-doped glass bulb 402, 502 nested substantially within the second interior volume defined by the truncated reflector 403, 503. In some embodiments, a ring (not shown) that surrounds the Nd-doped glass dome is utilized to affix the dome to the inside surface of the truncated diffuser.
As noted above, glass bulbs in accordance with some embodiments of this disclosure may include a nominally soda lime glass, having impregnation with a neodymium compound such as neodymium oxide. The same or similar proportions of Nd described hereinabove may be provided. Such glass bulbs may have a wall thickness of from about 0.1 mm to about 1 mm (for example, 0.5 mm). One function of the Nd-doped glass bulb is to absorb light from the LEDs when the apparatus is in operation, to induce a depression in a yellow portion of the visible light spectrum when light is transmitted therethrough, which provides enhanced red-green color contrast of illuminated objects as compared to conventional LED lamps. Such lamps thus hold great appeal to users for illuminating objects to cause the color of those objects to appear more rich or saturated. Descriptions of how Nd-doped glass bulbs may provide enhanced red-green color contrast can be found in U.S. Published Patent Application No. 2007/0241657, which has been incorporated by reference for all purposes herein.
Of course, other types of glass or glass bulbs are possible, provided they can modify a light source to induce a depression in a yellow portion of the visible light spectrum and increase red-green color contrast.
Referring again to
In the apparatus of the BR embodiment of
The circuit board 401, 501 may be affixed to the heat sink body 406, 506 by a mechanical connection and/or by an adhesive, for example, by a thermally conductive adhesive. In some embodiments, the circuit board may comprise a substantially planar metal-core printed circuit board (MCPCB).
In some embodiments, the capper is sized and shaped to accept the driver circuitry or electronics for the lamp, while still permitting the apparatus to attain the aspect or profile conforming to the ANSI A19 or BR30 profile. Typically, the capper comprises a polymer, such as a thermoplastic engineering polymer, for example, PBT. Some embodiments utilize a base (23, 117, 409, 509), which may be a threaded Edison base. The lighting apparatus may be characterized as being configured with components that mate with a lamp socket via a threaded Edison base connector. The lighting apparatus may be further characterized as being an integral lamp constructed as a unitary package including all components required to operate from standard electrical power received at the base thereof.
With reference to
The ring-shaped LED-based light source 150 is arranged tangential to the inside vertical surface of the toroidal diffuser 156 and emits its Lambertian illumination intensity 154 into the toroidal diffuser 156. The toroidal diffuser 156 preferably has a Lambertian-diffusing surface as diagrammatically illustrated in
The illustrated ring-shaped LED-based light source 150 is arranged tangential to the inside surface of the toroidal diffuser so that the illumination intensity pattern 154 is emitted most strongly in the horizontal, radial direction. In other embodiments, the ring-shaped LED-based light source 150 is arranged tangential to the bottom or top inside surface of the toroidal diffuser 156, or at any intermediate angular position along the inside surface of the toroidal diffuser 156.
In
The illustrated chimney 152 of
With returning reference to
The active heat sinking provided by the coolant fan 166 can optionally be replaced by passive cooling, for example by making the chimney of metal or another thermally conductive material, and optionally adding fins, pins, slots or other features to increase its surface area. In other contemplated embodiments, the chimney is replaced by a similarly sized heat pipe having a “cool” end disposed in a metal slug contained in the base 160. Conversely, in the embodiments of
The lamp depicted in
The LED replacement lamp of
In the several embodiments described herein, each of the plurality of LEDs may have a correlated color temperature of 2500 K-4000 K, for example, about 2700 K or about 3000 K. Furthermore, in some embodiments, each of the plurality of LEDs may have a color point substantially on the Planckian locus of the CIE diagram, so that the downward shift of the color point due to the Nd absorption does not result in the color point of the lamp being excessively far below the Planckian locus. In some implementations, each of the plurality of LEDs may have a color point substantially above the Planckian locus of the CIE diagram. Furthermore, in some embodiments, each of the plurality of LEDs has a CRI value of about 70 to about 97, for example, about 80, or about 90. For example, each of the plurality of LEDs may be a warm-white phosphor-converted LED, such as may be obtained from the Seoul Semiconductor Company as Model 5630, or from the Nichia Company as Model 757. In the embodiments described herein, each of the plurality of LEDs may be a package comprising a blue- or blue-violet emitting diode converted with a YAG:Ce phosphor, optionally with a red phosphor such as a Nitride Red phosphor.
In aspects described herein, the lighting apparatus as a whole substantially may conform to the ANSI A19 or BR30 profile. The lighting apparatus may be configured to be employed as a replacement lamp for 60 W incandescent lamps substantially conforming to the ANSI A19 profile, or for 65 W incandescent lamps substantially conforming to the ANSI BR30 profile. Of course, due to the efficiency of LEDs, such “60 W” or “65 W” replacement lamps may, in operation, be configured to operate between 5-25 Watts (W), for example, from 10 W to 20 W, or for example about 15 W.
In operation, the lighting apparatus in the embodiments of this disclosure is further characterized as having an attenuation, trough, or depression, in the spectrum of its emitted light in the region between about 565 nanometers (nm) to about 620 nm. That is, the spectrum of the emitted light may have a depression in its spectrum of emitted light in that region, as compared to the same lighting apparatus without the Nd-doped glass bulb. This region may be more narrowly defined as being between about 565 nm to about 595 nm, and in some implementations may be between about 575 nm and 590 nm. Furthermore, the lighting apparatus, in operation, may exhibit an attenuation, trough, or depression in the spectrum of its emitted light in the region between about 565 nm to about 620 nm of about 40% to about 80% (e.g., 50%), as compared to the same lighting apparatus without the Nd-doped glass bulb.
A lighting apparatus in accordance with the several embodiments disclosed herein may provide an enhanced red-green color contrast, enhanced overall color preference, and brighter, whiter appearance to illuminated objects. Furthermore, the lighting apparatus in accordance with the several embodiments may, in operation, emit light of correlated color temperature of about 2700 Kelvin (K) or about 3000 K with a color point below the Planckian locus of the CIE diagram. In addition, the lighting apparatus in accordance with disclosed embodiments may, in operation, emit light with a change in CCY value relative to the Planckian locus (DCCY) of about −0.005 to about −0.040, e.g., −0.01.
The above description and/or the accompanying drawing is 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.
This patent application claims the benefit of U.S. Provisional Patent Application No. 61/715,824 filed on Oct. 18, 2012, and on U.S. Provisional Patent Application No. 61/809,476 filed on Apr. 8, 2013, the contents of which are hereby incorporated by reference for all purposes.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4315186 | Hirano et al. | Feb 1982 | A |
| 5548491 | Karpen | Aug 1996 | A |
| 6323585 | Crane et al. | Nov 2001 | B1 |
| 6890085 | Hacker | May 2005 | B2 |
| 6940101 | Yano et al. | Sep 2005 | B2 |
| 7105989 | Lamouri et al. | Sep 2006 | B2 |
| 7453195 | Radkov | Nov 2008 | B2 |
| 7537356 | Huang et al. | May 2009 | B2 |
| 7736019 | Shimada et al. | Jun 2010 | B2 |
| 7858997 | Yoshimura et al. | Dec 2010 | B2 |
| 7942540 | Harbers et al. | May 2011 | B2 |
| 7965031 | Brunner et al. | Jun 2011 | B2 |
| 8030839 | Hosokawa et al. | Oct 2011 | B2 |
| 8089207 | Ramer et al. | Jan 2012 | B2 |
| 8104908 | Harbers et al. | Jan 2012 | B2 |
| 8169135 | Zhai et al. | May 2012 | B2 |
| 8220971 | Harbers et al. | Jul 2012 | B2 |
| 8235538 | Wei et al. | Aug 2012 | B2 |
| 8247959 | Beers et al. | Aug 2012 | B2 |
| 8253321 | Naum et al. | Aug 2012 | B2 |
| 8253336 | Maxik et al. | Aug 2012 | B2 |
| 8322896 | Falicoff et al. | Dec 2012 | B2 |
| 8414151 | Allen et al. | Apr 2013 | B2 |
| 8604684 | Pickard | Dec 2013 | B2 |
| 8931933 | Tong et al. | Jan 2015 | B2 |
| 20040212302 | Letz et al. | Oct 2004 | A1 |
| 20050175969 | Hayes | Aug 2005 | A1 |
| 20050253113 | Letz et al. | Nov 2005 | A1 |
| 20060071589 | Radkov | Apr 2006 | A1 |
| 20070241657 | Radkov et al. | Oct 2007 | A1 |
| 20080093615 | Lin et al. | Apr 2008 | A1 |
| 20100308356 | Wirth | Dec 2010 | A1 |
| 20100327306 | Van Der Burgt et al. | Dec 2010 | A1 |
| 20110058379 | Diamantidis | Mar 2011 | A1 |
| 20110080742 | Allen et al. | Apr 2011 | A1 |
| 20110084297 | Ogata et al. | Apr 2011 | A1 |
| 20110095686 | Falicoff et al. | Apr 2011 | A1 |
| 20110216523 | Tong et al. | Sep 2011 | A1 |
| 20110317283 | Shim | Dec 2011 | A1 |
| 20120043877 | Liang et al. | Feb 2012 | A1 |
| 20120049737 | Kitagawa | Mar 2012 | A1 |
| 20120057327 | Le et al. | Mar 2012 | A1 |
| 20120134133 | Kang | May 2012 | A1 |
| 20120155059 | Hoelen et al. | Jun 2012 | A1 |
| 20120155061 | Manabe et al. | Jun 2012 | A1 |
| 20120223632 | Hussell et al. | Sep 2012 | A1 |
| 20120250304 | Harbers et al. | Oct 2012 | A1 |
| 20120300432 | Matsubayashi et al. | Nov 2012 | A1 |
| 20120307492 | Ariyoshi et al. | Dec 2012 | A1 |
| 20130114265 | Sakumoto | May 2013 | A1 |
| 20130170199 | Athalye et al. | Jul 2013 | A1 |
| 20140049191 | Maxik | Feb 2014 | A1 |
| 20150146407 | Boonekamp et al. | May 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 2483596 | Aug 2012 | EP |
| 20120107071 | Sep 2012 | KR |
| 2009083867 | Jul 2009 | WO |
| 2009107038 | Sep 2009 | WO |
| 2010067817 | Jun 2010 | WO |
| 2011035668 | Mar 2011 | WO |
| 2011108203 | Sep 2011 | WO |
| 2011109099 | Sep 2011 | WO |
| 2012011460 | Jan 2012 | WO |
| 2012080934 | Jun 2012 | WO |
| 2013101537 | Jul 2013 | WO |
| Entry |
|---|
| PCT Search Report and Written Opinion dated Nov. 9, 2013 from corresponding Application No. PCT/US2013/065609. |
| Number | Date | Country | |
|---|---|---|---|
| 20150109758 A1 | Apr 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61715824 | Oct 2012 | US | |
| 61809476 | Apr 2013 | US |
