U.S. patent application number 13/420926 was filed with the patent office on 2012-09-20 for light bulb with adjustable light output.
Invention is credited to Ian Hardcastle, Fumitomo Hide, Timothy A. McCollum, Jeffery R. Parker, Alexey Titov.
Application Number | 20120236595 13/420926 |
Document ID | / |
Family ID | 46828321 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120236595 |
Kind Code |
A1 |
Parker; Jeffery R. ; et
al. |
September 20, 2012 |
LIGHT BULB WITH ADJUSTABLE LIGHT OUTPUT
Abstract
A light bulb includes a base; a light guide having opposed major
surfaces between which light propagates by total internal
reflection, a light input edge, and two light output regions of
different optical characteristics at least one of which is
associated with a corresponding one of the major surfaces; and a
light source electrically coupled to the base and located adjacent
the light input edge. The light source and the light guide are
variably positionable relative to one another to vary a location on
the light input edge at which light is input to the light guide
such that light is emitted from the light guide selectively
apportioned between the light output regions so that a
characteristic of the light output from the light bulb is modified
based on the optical characteristics associated with the light
output regions and the relative positioning of the light source and
the light guide.
Inventors: |
Parker; Jeffery R.;
(Richfield, OH) ; McCollum; Timothy A.; (Avon
Lake, OH) ; Hide; Fumitomo; (San Jose, CA) ;
Titov; Alexey; (Sagamore Hills, OH) ; Hardcastle;
Ian; (Sunnyvale, CA) |
Family ID: |
46828321 |
Appl. No.: |
13/420926 |
Filed: |
March 15, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61453756 |
Mar 17, 2011 |
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61602193 |
Feb 23, 2012 |
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61454221 |
Mar 18, 2011 |
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Current U.S.
Class: |
362/609 |
Current CPC
Class: |
F21V 9/30 20180201; F21V
14/02 20130101; G02B 6/005 20130101; G02B 6/0076 20130101; F21V
9/40 20180201; F21K 9/61 20160801; F21Y 2115/10 20160801; F21K 9/23
20160801; G02B 6/0073 20130101; G02B 6/0035 20130101; G02B 6/0058
20130101; F21V 13/14 20130101; F21K 9/64 20160801 |
Class at
Publication: |
362/609 |
International
Class: |
F21V 7/04 20060101
F21V007/04 |
Claims
1. A light bulb, comprising: a base configured to mechanically
mount the light bulb and receive electrical power; a light guide
comprising opposed major surfaces between which light propagates by
total internal reflection, a light input edge, and two light output
regions at least one of which is associated with a corresponding
one of the major surfaces, each light output region being
associated with a different optical characteristic; and a light
source electrically coupled to the base and located adjacent the
light input edge to input light into the light guide, the light
source and the light guide variably positionable relative to one
another to vary a location on the light input edge at which the
light is input to the light guide such that the light is emitted
from the light guide selectively apportioned between the light
output regions so that a characteristic of the light output from
the light bulb is modified based on the optical characteristics
associated with the light output regions and the relative
positioning of the light source and the light guide.
2. The light bulb of claim 1, wherein the light bulb further
comprises a heat sink thermally coupled to the light source.
3. The light bulb of claim 1, wherein the characteristic of the
light output from the light bulb that is modified is spectrum.
4. The light bulb of claim 1, wherein the characteristic of the
light output from the light bulb that is modified is color
temperature.
5. The light bulb of claim 1, wherein the characteristic of the
light output from the light bulb that is modified is light output
direction.
6. The light bulb of claim 1, wherein the optical characteristics
associated with the light output regions differ in an amount of a
single optical characteristic.
7. The light bulb of claim 6, wherein the optical characteristic is
at least one of reflective, diffusive, light redirecting,
polarizing, reflective polarizing, intensity reducing, wavelength
shifting and color attenuation.
8. The light bulb of claim 1, wherein the optical characteristic
associated with a first one of the light output regions imposes a
first characteristic on the output light, the optical
characteristic associated with a second one of the light output
regions imposes a different characteristic on the output light, and
the optical characteristics are at least one of reflective,
diffusive, light redirecting, polarizing, reflective polarizing,
intensity reducing, wavelength shifting and color attenuation.
9. The light bulb of claim 1, further comprising an optical
adjuster comprising a major surface juxtaposed with and conforming
to one of the major surfaces of the light guide and wherein the
association of optical characteristics with the light output
regions is achieved by respective optical adjuster regions of the
optical adjuster aligned with the light output regions.
10. The light bulb of claim 9, wherein the optical adjuster is a
first optical adjuster and the light bulb further comprises a
second optical adjuster superposed with the first optical adjuster,
the second optical adjuster comprising optical adjuster regions
with different optical characteristics to increase the number of
light output characteristics of the light bulb based on the optical
characteristics of the second optical adjuster and the relative
positioning of the light source and the light guide.
11. The light bulb of claim 9, wherein the optical adjuster is a
first optical adjuster and the light bulb further comprises a
second optical adjuster comprising a major surface juxtaposed with
and conforming to the other of the major surfaces of the light
guide, wherein the second optical adjuster has optical adjuster
regions with different optical characteristics.
12. The light bulb of claim 11, wherein the first optical adjuster
has a transmissive optical adjuster region and a reflective optical
adjuster region, and the second optical adjuster has a reflective
optical adjuster region aligned with the transmissive optical
adjuster region of the first optical adjuster and has a
transmissive optical adjuster region aligned with the reflective
optical adjuster region of the first optical adjuster.
13. The light bulb of claim 12, wherein at least one of the
transmissive optical adjuster regions additionally is at least one
of diffusive, light redirecting, polarizing, intensity reducing,
wavelength shifting and color attenuating.
14. The light bulb of claim 1, wherein the light guide further
comprises: first light extracting elements at at least one of the
major surfaces of the light guide, the first light extracting
elements defining a first one of the light output regions; and
second light extracting elements at at least one of the major
surfaces of the light guide, the second light extracting elements
defining a second one of the light output regions, the first and
second light extracting elements respectively configured to achieve
the different optical characteristics associated with the first
light output region and the second light output region.
15. The light bulb of claim 14, wherein the first light extracting
elements differ from the second light extracting elements in at
least one of size, shape, depth or height, density, orientation,
slope angle and index of refraction such that the first light
output region outputs light with a different intensity profile than
the second light output region.
16. The light bulb of claim 14, wherein the first light extracting
elements differ from the second light extracting elements in at
least one of size, shape, depth or height, density, orientation,
slope angle and index of refraction such that the first light
output region outputs light with a different light ray angle
distribution than the second light output region.
17. The light bulb of claim 14, wherein the light extracting
elements are light-scattering elements.
18. The light bulb of claim 14, wherein the light extracting
elements have well-defined shapes.
19. The light bulb of claim 14, wherein the light extracting
elements are micro-optical elements.
20. The light bulb of claim 1, wherein the light source is a solid
state light source.
21. The light bulb of claim 1, wherein each light output region is
associated with the same one of the major surfaces.
22. The light bulb of claim 1, wherein each light output region is
associated with a respective one of the major surfaces.
23. The light bulb of claim 1, wherein one of the light output
regions is associated with one of the major surfaces and the other
of the light output regions is associated with an edge of the light
guide opposite the light input edge.
24. A light bulb, comprising: a base configured to mechanically
mount the light bulb and receive electrical power; a first light
guide comprising opposed inner and outer major surfaces between
which light propagates by total internal reflection, a light input
edge, and a light output region associated with an optical
characteristic; a second light guide comprising opposed inner and
outer major surfaces between which light propagates by total
internal reflection, a light input edge, and a light output region
associated with an optical characteristic, the inner major surface
of the second light guide juxtaposed and conforming to the inner
major surface of the first light guide; and a light source
electrically coupled to the base and located adjacent the light
input edges, the light source and the light input edges variably
positionable relative one another to selectively apportion light
between an amount of light input into the first light guide and
output from the light output region of the first light guide and an
amount of light input into the second light guide and output from
the light output region of the second light guide so that a
characteristic of the light output from the light bulb is modified
based on the optical characteristics associated with the light
output regions and the relative positioning of the light source and
the light input edges.
25. The light bulb of claim 24, wherein each light output region is
associated with the respective one of the outer major surfaces.
26. The light bulb of claim 24, wherein each light output region is
associated with the outer major surface of the other light
guide.
27. The light bulb of claim 24, wherein one of the light output
regions is associated with the respective one of the outer major
surfaces and the other of the light output regions is associated
with an edge of the respective light guide opposite the respective
light input edge.
28. The light bulb of claim 24, wherein the light guides have
respective light extracting elements.
29. The light bulb of claim 24, wherein the relative positioning of
the light source and the light input edges determines an amount of
the light that exits through the outer major surface of the first
light guide and an amount of the light that exits through the outer
major surface of the second light guide.
30. The light bulb of claim 24, wherein the relative positioning of
the light source and the light input edges determines an amount of
the light that exits through one or both of the outer major
surfaces and an amount of the light that exits through an edge of
one of the light guides opposite the corresponding light input
edge.
31. The light bulb of claim 24, wherein the light source is a solid
state light source.
32. A light bulb, comprising: a base configured to mechanically
mount the light bulb and receive electrical power; a housing
mechanically coupled to the base; a light source electrically
coupled to the base and mechanically coupled to the housing; and a
light guide mechanically coupled to the housing so as to be
variably positionable relative to the light source, the light guide
comprising opposed major surfaces between which light propagates by
total internal reflection, a light input edge, and light extracting
elements at at least one of the major surfaces, wherein the light
guide is positionable between a first position where the light
input edge is adjacent the light source such that the light guide
is edge lit by the light source and a second position where the
light guide is not edge lit by the light source.
33. The light bulb of claim 32, wherein the light extracting
elements are configured to extract light from the light guide with
a diffuse light ray angle distribution.
34. The light bulb of claim 32, further comprising an optical
adjuster mechanically coupled to the housing and variably
positionable relative to the light source such that when the light
guide is in the second position the optical adjuster is aligned
with the light source.
35. The light bulb of claim 34, wherein the optical adjuster
comprises a lens.
36. The light bulb of claim 35, wherein the lens is a collimating
lens.
37. The light bulb of claim 36, wherein when the light guide is in
the second position, the light is emitted with a narrower light ray
angle distribution than when the light guide is in the first
position.
38. The light bulb of claim 34, further comprising an adjustment
member mechanically coupled to the housing, wherein the light guide
and the optical adjuster are coupled to the adjustment member, and
the adjustment member is variably positionable relative to the
housing to move the light guide between the first and second
positions and move the optical adjuster into alignment with the
light source when the light guide is in the second position.
39. The light bulb of claim 38, wherein the adjustment member has
increased resistance to movement when the light guide is in the
first and second positions relative to when the light guide is not
in one of the first position or the second position.
40. The light bulb of claim 38, wherein the housing comprises
cooling air vents through which air flows to dissipate heat
generated by the light source and the adjustment member comprises
openings that align with the cooling air vents of the housing at
least when the light guide is in the first position and the second
position.
41. The light bulb of claim 32, wherein the light source is a solid
state light source.
42. The light bulb of claim 32, wherein the base comprises an
Edison screw base.
Description
RELATED APPLICATION DATA
[0001] This application claims the benefit of U.S. Provisional
Patent Application Nos. 61/453,756 (filed Mar. 17, 2011),
61/454,221 (filed Mar. 18, 2011), and 61/602,193 (filed Feb. 23,
2012), the disclosures of which are incorporated herein by
reference in their entireties.
BACKGROUND
[0002] Energy efficiency has become an area of interest for energy
consuming devices. One class of energy consuming devices is
lighting devices. Light emitting diodes (LEDs) show promise as
energy efficient light sources for lighting devices. But control
over color and light output distribution is an issue for lighting
devices that use LEDs or similar light sources.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a schematic view of a light bulb representing an
exemplary lighting assembly with adjustable light output, where a
portion of a housing of the light bulb is cut away to show a light
source assembly;
[0004] FIG. 2 is a schematic view of a lighting fixture
representing another exemplary lighting assembly with adjustable
light output;
[0005] FIGS. 3-5 are schematic views showing part of an embodiment
of a lighting assembly having adjustable light output;
[0006] FIG. 6 is a schematic view showing part of an embodiment of
a lighting assembly having adjustable light output;
[0007] FIG. 7 is a schematic view showing part of an embodiment of
a lighting assembly having adjustable light output;
[0008] FIGS. 8-10 are schematic views showing part of an embodiment
of a lighting assembly having adjustable light output;
[0009] FIG. 11 is a schematic view showing part of an embodiment of
a lighting assembly having adjustable light output;
[0010] FIG. 12 is a schematic view showing part of an embodiment of
a lighting assembly having adjustable light output;
[0011] FIGS. 13-20 are schematic views showing part of an
embodiment of a lighting assembly having adjustable light
output;
[0012] FIG. 21 is an exploded view of another embodiment of a
lighting assembly having adjustable light output;
[0013] FIG. 22 is a perspective view of the lighting assembly of
FIG. 21; and
[0014] FIG. 23 is a top view of the lighting assembly of FIG.
21.
DETAILED DESCRIPTION
[0015] Embodiments will now be described with reference to the
drawings, wherein like reference numerals are used to refer to like
elements throughout. The figures are not necessarily to scale.
Features that are described and/or illustrated with respect to one
embodiment may be used in the same way or in a similar way in one
or more other embodiments and/or in combination with or instead of
the features of the other embodiments.
[0016] Aspects of this disclosure relate to a lighting assembly. As
illustrated in FIG. 1, one type of lighting assembly 10 is a light
bulb 12. As illustrated in FIG. 2, another type of lighting
assembly 10 is a lighting fixture 14.
[0017] As described in greater detail below, the lighting assembly
includes a light guide having opposed major surfaces between which
light propagates by total internal reflection, a light input edge,
and two light output regions at least one of which is associated
with one of the major surfaces. Each light output region is
associated with a different optical characteristic. The lighting
assembly also includes a light source located adjacent the light
input edge to input light into the light guide. The light source
and the light guide are variably positionable relative to one
another to vary the location on the light input edge at which the
light is input to the light guide such that the light is emitted
from the light guide selectively apportioned between the light
output regions. In this manner, a characteristic of the light
output from the lighting assembly is modified based on the optical
characteristics associated with the light output regions and the
relative positioning of the light source and the light guide.
[0018] In the case of the light bulb 12, the light bulb 12
additionally includes a base configured to mechanically mount the
light bulb and receive electrical power.
[0019] With additional reference to FIG. 3, the lighting assembly
10, whether a bulb 12, a lighting fixture 14, or another type of
lighting device, will be described in greater detail. The lighting
assembly 10 includes a light source assembly 16 (FIGS. 1 and 2).
The light source assembly 16 includes one or more light sources 18.
Each light source 18 is typically embodied as one or more
solid-state devices. In one embodiment, the light sources 18 are
mounted to a printed circuit board (PCB) 19 (FIG. 1).
[0020] Exemplary light sources 18 include solid state devices such
as LEDs, laser diodes, and organic LEDs (OLEDs). In an embodiment
where the light source 18 is one or more LEDs, the LEDs may be
top-fire LEDs or side-fire LEDs, and may be broad spectrum LEDs
(e.g., emit white light) or LEDs that emit light of a desired color
or spectrum (e.g., red light, green light, blue light, or
ultraviolet light). In one embodiment, the light source 18 emits
light with no operably-effective intensity at wavelengths greater
than 500 nanometers (nm) (i.e., the light source 18 emits light at
wavelengths that are predominantly less than 500 nm). Although not
specifically illustrated, the light source assembly 16 also
includes structural components (e.g., PCB 19) to retain the light
sources 18. The light source assembly 16 may additionally include:
circuitry, power supply and/or electronics for controlling and
driving the light sources 18, a heat sink, and any other
appropriate components.
[0021] The lighting assembly 10 also includes a light guide 20.
Light from the light sources 18 is input into the light guide 20.
The light guide 20 is a solid article made from, for example,
acrylic, polycarbonate, glass, or another appropriate material. The
light guide 20 also may be a multi-layer light guide having two or
more layers. The light guide 20 has opposed major surfaces 22 and
24. Depending on the configuration of the light guide 20, the light
guide has at least one edge. For instance, in a case where the
light guide 20 is shaped like a dome, the light guide has one edge.
In a case where the light guide 20 is a hollow cylinder (e.g., as
shown in FIGS. 1 and 7), is frustroconical, is a frustrated
pyramid, is a dome with a hole cut at the dome's apex, or another
similar shape, the light guide has two opposed edges. Other light
guide 20 shapes for either a light bulb 12 or a lighting fixture 14
are possible, such as a globe or a shape approximating the bulbous
shape of a conventional incandescent bulb. In one embodiment, a
light bulb configuration or a lighting fixture configuration may be
established using planar or curved light guides 20 that are
arranged in a three-dimensional geometric (e.g., polygonal)
configuration. In the case where the light guide 20 is rectangular
(e.g., as shown in FIGS. 2 and 3), the light guide 20 has four
edges. Other geometries for the light guide 20 result in a
corresponding number of edges. Depending on the geometry of the
light guide 20, each edge may follow a straight path or a curved
path, and adjacent edges may meet at a vertex or join in a
curve.
[0022] One of the edges serves as a light input edge 26. In some
embodiments, the light input edge 26 is an external edge of the
light guide 20 (e.g., as shown in FIGS. 1 and 2). In embodiments,
the light input edge 26 is an internal edge of the light guide 20,
which is an edge completely surrounded by the light guide 20 and is
usually an edge of a hole 42 that extends between the major
surfaces of the light guide 20 (e.g., as shown in FIG. 6). Light
output from the light sources 18 is directed toward the light input
edge 26. Additional optical elements (e.g., lenses, reflectors,
etc.) may be present to assist in inputting the light into the
light guide 20. Once input into the light guide 20, the light
propagates through the light guide by total internal reflection
(TIR) at the opposed major surfaces 22, 24. For purposes of this
disclosure, any light input surface of the light guide 20 is
considered a light input edge, even if it is located on one of the
major surfaces 22, 24 or forms part of a light turning and/or
homogenizing structure to introduce light between the major
surfaces 22, 24 in a manner that allows the light to propagate
along the light guide 20 by total internal reflection at the major
surfaces 22, 24.
[0023] Length and width dimensions of each of the major surfaces
22, 24 are much greater than, typically ten or more times greater
than, the thickness of the light guide 20. For instance, in the
rectangular embodiment shown in FIG. 2, the length (measured from
the light input edge 26 to an opposite edge distal the light input
edge 26) and the width (measured along the light input edge 26) of
the light guide 20 are both much greater than the thickness of the
light guide 20. The thickness is the dimension of the light guide
20 in a direction orthogonal to the major surfaces. The thickness
of the light guide 20 may be, for example, about 0.1 millimeters
(mm) to about 10 mm. The light guide 20 may be rigid or
flexible.
[0024] With continuing reference to FIG. 3, the light guide 20
includes light extracting elements 27 in or on at least one of the
major surfaces 22, 24. Although not specifically illustrated in
connection with each light guide 20 shown in the appended drawing
figures, each light guide 20 includes light extracting elements 27
in a configuration to achieve the described light extracting
functions.
[0025] Light extracting elements 27 that are in or on a major
surface 22, 24 will be referred to as being "at" the major surface
22, 24. Each light extracting element 27 functions to disrupt the
total internal reflection of the propagating light that is incident
on the light extracting element 27. In one embodiment, the light
extracting elements 27 reflect light toward the opposing major
surface so that the light exits the light guide 20 through the
opposing major surface. Alternatively, the light extracting
elements 27 transmit light through the light extracting elements 27
and out of the major surface 22, 24 of the light guide 20 having
the light extracting elements 27. In another embodiment, both of
these types of light extracting elements 27 are present. In yet
another embodiment, the light extracting elements 27 reflect some
of the light and refract the remainder of the light incident
thereon. Therefore, the light extracting elements 27 are configured
to extract light from one or both of the major surfaces 22, 24.
[0026] Light extracting elements 27 are arranged at a major surface
22, 24 to extract light from one or more distinct light output
regions 28, 30 of one or both of the major surfaces 22, 24. It is
possible that a light output region occupies part or all of one of
the major surfaces 22, 24.
[0027] The location of the light source 18 relative to the light
guide 20, the angular range 32 of light output from the light
source 18, and the configuration of the light extracting elements
27 determine the portion of the light that exits through each light
output region 28, 30. The light extracting elements 27 for each
light output region may be at one or both of the major surfaces 22,
24 through which light is emitted, or at the opposite major surface
22, 24. Light guides having such light extracting elements 27 are
typically formed by a process such as stamping, molding, embossing,
extruding, laser etching, chemical etching, or another suitable
process. Light extracting elements 27 may also be produced by
depositing elements of curable material on the light guide 20 and
curing the deposited material using heat, UV-light or other
radiation. The curable material can be deposited by a process such
as printing, ink jet printing, screen printing, or another suitable
process. Alternatively, the light extracting elements 27 may be
inside the light guide between the major surfaces 22, 24 (e.g., the
light extracting elements 27 may be light redirecting particles
and/or voids disposed in the light guide).
[0028] The light extracting elements 27 are configured to extract
light in a defined intensity profile, such as uniform intensity,
and/or a defined light ray angle distribution over the light output
region. Using variations in the light extracting elements 27, each
light output region need not have the same intensity profile and/or
light ray angle distribution. Intensity profile refers to the
variation of intensity with position within a light-emitting region
(such as light output region 28 or light output region 30). Light
ray angle distribution refers to the variation of intensity with
ray angle (typically a solid angle) of light emitted from a
light-emitting region (such as light output region 28 or light
output region 30).
[0029] Exemplary light extracting elements 27 include
light-scattering elements, which are typically features of
indistinct shape or surface texture, such as printed features, ink
jet printed features, selectively-deposited features, chemically
etched features, laser etched features, and so forth. Other
exemplary light extracting elements 27 include features of
well-defined shape, such as V-grooves, lenticular grooves, and
features of well-defined shape that are small relative to the
linear dimensions of the major surfaces 22, 24, which are sometimes
referred to as micro-optical elements. The smaller of the length
and width of a micro-optical element is less than one-tenth of the
longer of the length and width of the light guide 20, and the
larger of the length and width of the micro-optical element is less
than one-half of the smaller of the length and width of the light
guide. The length and width of the micro-optical element is
measured in a plane parallel to the major surface 22, 24 of the
light guide 20 for flat light guides 20 or along a surface contour
for non-flat light guides 20.
[0030] Micro-optical elements are shaped to predictably reflect
light or predictably refract light. However, one or more of the
surfaces of the micro-optical elements may be modified, such as
roughened, to produce a secondary effect on light output. Exemplary
micro-optical elements are described in U.S. Pat. No. 6,752,505
and, for the sake of brevity, will not be described in detail in
this disclosure. The micro-optical elements may vary in one or more
of size, shape, depth or height, density, orientation, slope angle,
or index of refraction such that a desired light output from the
light guide 20 is achieved over the corresponding light output
region 28.
[0031] FIGS. 3-5 schematically illustrate one embodiment of
components of the lighting assembly 10 that are operative to modify
a characteristic of the light output of the lighting assembly 10.
In this embodiment, the light guide 20 has a first light output
region 28 and a second light output region 30. As illustrated,
there is more than one first light output region 28 and more than
one second light output region 30. In embodiments where there are
more than one set of two or more light output regions, each set of
light output regions is associated with a respective light source
18. The light source 18 has an angular range 32, which is the range
of light ray angles within which a predominant amount of the light
is emitted by the light source.
[0032] The first light output region 28 has an optical
characteristic that is different than an optical characteristic of
the second light output region 30. The optical characteristics in
the embodiment of FIGS. 3-5 are each provided by a material
property of the region 28, 30 or optical characteristic-affecting
structure of the region 28, 30. The different optical
characteristics are indicated by different types of surface
hatching in the appended figures. The different optical
characteristics may be two different types of optical
characteristic or different amounts of the same type of optical
characteristic. Exemplary optical characteristics of the light
output regions 28, 30 include specularly transmissive, reflective,
diffusive, light redirecting, polarizing, reflective polarizing,
intensity reducing, wavelength shifting and color attenuating.
Wavelength shifting is used herein to refer to a process in which a
material absorbs light at certain wavelengths, and reemits the
light at one or more different wavelengths. Wavelength shifting may
be achieved using a phosphor material, a luminescent material, a
luminescent nanomaterial such as a quantum dot material, a
conjugated polymer material, an organic fluorescent dye, an organic
phosphorescent dye, lanthanide-doped garnet, or the like. Color
attenuating may be achieved using color filtering material.
[0033] In the illustrated embodiments, the change in optical
characteristic from the first light output region 28 to the second
light output region 30 is abrupt. In an embodiment, a barrier (not
shown) is provided between the first light output region 28 and the
second light output region 30 to reduce light leakage between the
output regions. In an example, a groove extending into the light
guide 20 from one or both major surfaces 22, 24 at the boundary
between the output regions serves as the barrier. Reflective or
opaque material may be located in the groove. For example, the
groove walls may be coated with reflective material. In other
embodiments, the transition between the first region 28 and the
second region 30 is gradual. A gradual transition may be
appropriate where at least one of the regions 28, 30 has an optical
characteristic related to intensity reducing, wavelength shifting
or color attenuating, but also may be used in other situations. The
effect that the light output regions 28, 30 have on light that is
output from the lighting assembly 10 will be described in greater
detail below.
[0034] Each set of light output regions, e.g., light output regions
28, 30, has at least one light source 18 to generate light that is
output through the light output regions 28, 30 in amounts
apportioned between the light output regions 28, 30 dependent on
the relative positioning of the light guide 20 and the light source
18. More specifically, one or both of the light guide 20 and the
light source 18 is variably positionable relative to the other. The
location at which the light from light source 18 is input to the
light guide 20 determines where the light exits the light guide 20.
For example, in FIG. 3, the light source 18 is located adjacent the
light input edge 26 in an area of the light input edge 26
corresponding to the first light output region 28. Therefore, more
of the light from the light source 18 exits the light guide 20 by
way of the first light output region 28 than exits by way of the
second light output region 30.
[0035] In the examples shown in FIGS. 4 and 5, the light source 18
has been moved laterally by respective distances relative to the
position shown in FIG. 3 to change the position of the light source
18 relative to the light guide 20 and produce a corresponding
change in the portion of the light from the light source 18 that
exits the first output region 28 and, correspondingly, the portion
of the light from the light source 18 that exits the second output
region 30. In another example (not shown), light guide 20 is moved
laterally to change its position relative to the light source 18 to
produce a similar effect. In one embodiment, and as shown in FIG.
3, the relative positioning is varied so that more of the light
emitted from the light source 18 exits the first light output
region 28 than exits the second light output region 30. Also, as
shown in FIG. 5, the relative positioning is varied so that more of
the light that is emitted from the light source 18 exits the light
guide by way of the second light output region 30 than exits the
light guide by way of the first light output region 28. Also, as
shown in FIG. 4, the relative positioning is varied so that similar
portions of the light from the light source 18 exit the first light
output region 28 and the second light output region 30. Locating a
barrier between the first light output region 28 and the second
light output region 30, as described above, increases the ratio
between the amount of the light that exits the light guide by way
of the first light output region 28 and that which exits the light
guide by way of the second light output region 30 in the example
shown in FIG. 3, and vice versa in the example shown in FIG. 5.
[0036] The variable relative positioning illustrated in FIGS. 3-5
allows for selectively apportioning light that is output from the
lighting assembly 10 between the light that is output by way of the
first light output region 28 and the light that is output by way of
the second light output region 30. The light output by way of the
first light output region 28 is modified by the optical
characteristic of the first light output region 28 and the light
output by way of the second light output region 30 is modified by
the optical characteristic of the second light output region 30.
Therefore, the overall characteristic of the light output from the
lighting assembly 10 is modified based on the optical
characteristics associated with the light output regions and the
relative positioning of the light source 18 and the light guide
20.
[0037] In one embodiment, the relative positioning is varied
manually by a user. In the example shown in FIG. 1, the lighting
assembly 10 includes a user-manipulable mechanism 34 that moves one
or both of the light guide 20 and the light source 18 relative to
the other to vary the relative positioning of the light guide 20
and the light source 18. As shown in FIG. 1, the light source 18 is
fixed relative to a housing 36 and the light guide 20 is rotatably
moveable relative thereto by the manual application of force to the
mechanism 34. In the embodiment of FIG. 1, the mechanism 34 is a
member that is secured to the light guide 20 and slides over a
portion of the housing 36 of the light bulb 12. In one embodiment,
the amount of movement is limited by stops (not illustrated). Other
manually-operated mechanisms are possible. For instance, other
types of sliders may be employed or a turnable knob may act on the
moveable component through a gear or drive train. In other
embodiments, the mechanism 34 is motorized to move one or both of
the light guide 20 and the light source 18 relative to the other.
The motorized mechanism may be controlled by a control assembly
(not shown) to adjust light output based on user input, feedback
from sensors, or a triggering event. In still other embodiments,
there is no mechanism 34 and the adjustment is made by applying a
positioning force, which in the case of the exemplary cylinder is
torque, directly to the moveable one of the light source assembly
16 and the light guide 20.
[0038] Once positioned, the relative positioning of the light guide
20 and the light source 18 remains unchanged until the user or
control assembly varies the relative positioning. Since constant
motion of the light guide 20 relative to the light source 18 is not
contemplated during operation of the lighting assembly 10, the
range of movement of the light guide 20 and/or the light source 18
may be limited. The range of movement may be limited to
back-and-forth sliding that moves the regions 28, 30 in and out of
alignment with the light source 18, rather than allowing infinite
movement of the light guide 20 or the light source 18 in one
direction.
[0039] A visual indicator may be present to provide the user with
an indication of the characteristic of the light output by the
lighting assembly 10. In the illustrated embodiment of FIG. 1, for
example, markings 38 are present on the light guide 20 and align
relative to a pointer 40 on the housing to provide this
indication.
[0040] With additional reference to FIG. 6, schematically
illustrated is another embodiment of part of the lighting assembly
10 having an adjustable light output. In this embodiment, a
disk-shaped light guide 20 has two sets of two light output regions
28, 30. The light output regions 28, 30 have different optical
characteristics. The light guide has a hole 42 that extends between
the major surfaces 22, 24 of the light guide 20, typically at its
center. The edge of the hole 48 provides the light input edge 26 of
the light guide 20 in this embodiment. Light from each light source
18 is input to light guide 20 through the light input edge 26. The
variable relative positioning of the light guide 20 and the light
sources 18 selectively apportions the light emitted by each light
source 18 between the light output and modified by the first light
output region 28 and the light output and modified by the second
light output region 30.
[0041] With additional reference to FIG. 7, schematically
illustrated is another embodiment of part of the lighting assembly
10 having an adjustable light output. In this embodiment, a hollow
cylindrical light guide 20 has the two light output regions 28, 30
having different optical characteristics. Light is input through
the light input edge 26, which is an edge along one end of the
light guide 20. The variable relative positioning of the light
guide 20 and the light source 18 selectively apportions light
between the light output and modified by the first light output
region 28 and the light output and modified by the second light
output region 30.
[0042] With additional reference to FIGS. 8-10, schematically
illustrated is another embodiment of part of the lighting assembly
10 having an adjustable light output. In this embodiment, the light
output regions of the light guide 20 do not have different optical
characteristics (e.g., there may be no discernable differences in
the light guide 20 to form distinct regions), but the area of the
light guide 20 that outputs light depends on the variable relative
positioning of light source 18 and the light guide 20. Typically,
the area that outputs light is aligned with the light source 18.
For instance, using the respective relative positions shown in the
FIGS. 8-10, when the light source 18 is positioned to the right 42
of the light input edge 26, as shown in FIG. 8, more of the light
exits through the second light output region 30 of light guide 20
than through the first light output region 28. Following this
example, when the light source 18 is positioned near the middle of
the light input edge 26, as shown in FIG. 9, the light is
apportioned approximately equally between first light output region
28 and second output region 30 with the apportionment depending on
the relative positioning of the light source 18 and light guide 20.
When the light source 18 is positioned to the left 44 of the light
input edge 26, as shown in FIG. 10, more of the light exits through
the first light output region 28 of the light guide 20 than through
the second light output region 30. In a manner similar to that
described above, a barrier (not shown) may be used to define
optically-isolated light output regions 28, 30 in the light guide
20.
[0043] In the embodiments of FIGS. 8-10, to achieve the desired
modification of the light output based on the relative positioning
of the light source 18 and the light guide 20, the lighting
assembly 10 further includes an optical adjuster 46. The optical
adjuster 46 has a fixed position relative to the light guide 20.
The optical adjuster 46 has opposed major surfaces 48 and 50. In
the illustrated embodiment, the major surface 50 of the optical
adjuster 46 is juxtaposed with the major surface 22 of the light
guide 20 and conforms to the surface contour of the light guide 20.
The major surface 50 of the optical adjuster 46 that faces the
light guide 20 is separated from major surface 22 so that the
optical adjuster 46 does not disrupt the total internal reflection
within the light guide 20. In the embodiment where the light guide
20 is planar (e.g., as shown in FIGS. 8-10), the optical adjuster
46 is planar and located adjacent the major surface 22. The optical
adjuster 46 is located such that at least a portion of the light
output from the light guide 20 is incident thereon. In another
embodiment in which the light guide 20 is configured as a hollow
cylinder, such as is shown in FIG. 1, the optical adjuster 46 is
also a hollow cylinder and positioned either inside the light guide
20 or outside the light guide 20, and is coaxial therewith.
[0044] The optical adjuster 46 has two or more optical adjuster
regions. In the embodiment of FIGS. 8-10, for example, the optical
adjuster 46 has a first optical adjuster region 52 and a second
optical adjuster region 54. The first optical adjuster region 52
has an optical characteristic that is different than an optical
characteristic of the second optical adjuster region 54. The
different optical characteristics are denoted by the surface
hatching in the appended figures. The different optical
characteristics may be two different types of optical
characteristic or different amounts of the same type of optical
characteristic. In the illustrated embodiments, the change in
optical characteristic from the first optical adjuster region 52 to
the second optical adjuster region 54 is abrupt. In other
embodiments, the transition between the regions 52, 54 may be
gradual.
[0045] The optical adjuster region 52 of the optical adjuster 46 is
aligned with the first light output region 28 of the light guide 20
and is, therefore, associated with the first light output region
28. Similarly, the optical adjuster region 54 the optical adjuster
46 is aligned with the second light output region 30 of the light
guide 20 and is, therefore, associated with the second light output
region 30. The optical characteristics of the optical adjuster
regions combine with the optical characteristics of the respective
light output regions with which they are associated to modify the
characteristics of the light output of the lighting assembly 10.
Examples of the characteristics of the light output modified by the
optical characteristics of the light output regions are intensity
profile, light ray angle distribution, spectrum, polarization, and
coherence.
[0046] Light output from the major surface 22 of light guide 20 is
incident on the optical adjuster 46. Depending on the relative
positioning of the light source 18 and the light guide 20, the
light incident on the optical adjuster 46 is modified by the
optical characteristic of the first optical adjuster region 52
and/or is modified by the optical characteristic of the second
optical adjuster region 54. As shown in FIG. 10, when the position
of the light source 18 relative to the light guide 20 is such that
more of the light from the light source 18 is output from the first
light output region 28 of the light guide 20 than is output from
the second light output region 30 of the light guide 20, more of
the light that is emitted from the light guide 20 is incident on
the first optical adjuster region 52 and is modified by the optical
characteristic thereof than is incident on the second optical
adjuster region 54 and is modified by the optical characteristic
thereof As shown in FIG. 8, when the position of the light source
18 relative to the light guide 20 is such that more of the light
from the light source 18 is output from the second light output
region 30 of the light guide 20 than is output from the first light
output region 28 of the light guide, more of the light that is
emitted from the light guide 20 is incident on the second optical
adjuster region 54 and is modified by the optical characteristic
thereof than is incident on the first optical adjuster region 52
and is modified by the optical characteristic thereof Also, as
shown in FIG. 9, when light output by the light guide 20 and
incident on the optical adjuster 46 is apportioned between a
portion of the first optical adjuster region 52 and a portion of
the second optical adjuster region 54, the light is proportionally
modified by the optical characteristics of the first optical
adjuster region 52 and the second optical adjuster region 54. In
this manner, a characteristic of the light output from the lighting
assembly 10 is modified based on the respective effects of the
optical adjuster regions 52, 54 on the light, which depend on the
apportionment of the light between the optical adjuster regions 52,
54. The apportionment in turn depends on the relative positioning
of the light source 18 and the light guide 20.
[0047] In a variation of this embodiment, the light output regions
28, 30 each have different optical characteristics. In this
variation, the first light output region 28 is aligned with the
first optical adjuster region 52 and the second light output region
30 is aligned with the second optical adjuster region 54, as
illustrated. Alternatively, a portion of the second optical
adjuster region 54 may overlap with the first light output region
28 or a portion of the first optical adjuster region 52 may overlap
with the second light output region 30. In these variations, the
light output from the light guide 20 is initially modified by the
optical characteristic of the one or more of the first or second
light output region 28, 30 through which the light passes and is
further modified by the optical characteristic of the one or more
of the first or second optical adjuster region 52, 54 through which
the light passes.
[0048] One or more additional optical adjusters may be located
between the optical adjuster 46 and the light guide 20. One or more
additional optical adjusters may be located adjacent the major
surface 48 of the optical adjuster 46 that faces away from the
light guide 20. If present, each additional adjuster may have a
single optical characteristic or multiple optical
characteristics.
[0049] As illustrated in FIG. 11, an additional optical adjuster 58
is located adjacent the optical adjuster 46. The additional optical
adjuster 58 of the illustrated embodiment is superposed with the
optical adjuster 46 and has three optical adjuster regions 60, 62
and 64, each of which has a respective optical characteristic to
further modify light output by the lighting assembly 10. Like the
optical adjuster 46, the additional optical adjuster 58 has a fixed
position relative to the light guide 20. In another embodiment, the
additional optical adjuster 58 and the light guide 20 are variably
positionable relative to one another. The light output from the
light guide 20 is modified by various combinations of the adjuster
regions of the optical adjusters 46, 58 depending on the variable
relative positioning of the light source 18 and the light guide 20,
and additionally depending on the variable relative positioning of
the additional optical adjuster 58 and the light guide 20 in
embodiments in which this feature is implemented.
[0050] As another example, as illustrated in FIG. 12, the
additional optical adjuster 58 having more than one optical
adjuster region that each has a respective optical characteristic
to further modify light output by the lighting assembly 10 is
located adjacent the opposite side of the light guide 20 from the
optical adjuster 46. In the illustrated embodiment, the additional
optical adjuster 58 has a first optical adjuster region 66 aligned
with the first optical adjuster region 52 of the optical adjuster
46, and has a second optical adjuster region 68 aligned with the
second optical adjuster region 54 of the first optical adjuster 46.
Also, the light guide 20 outputs light from both major surfaces 22
and 24. However, the area of the major surfaces 22, 24 of the light
guide from which the light is output depends on the variable
relative positioning of the light guide 20 and the light source
18.
[0051] In one configuration, and as illustrated, the optical
adjuster regions 52 and 68 are transmissive and the optical
adjuster regions 54 and 66 are reflective. In one embodiment, in
addition to being transmissive, the optical adjuster regions 52 and
68 have at least one additional optical characteristic, such as
diffusive, light redirecting, polarizing, intensity reducing,
wavelength shifting or color attenuating. In this manner, light
output from the first light output region 28 of first major surface
22 and incident on the first optical adjuster region 52 exits the
lighting assembly 10 in a direction away from the first major
surface 22 as indicated by arrow 70. As indicated by arrow 72,
light output from the first light output region 28 of the second
major surface 24 of light guide 20 is incident on the first optical
adjuster region 66 that reflects the light back through the second
major surface 24, through the light guide 20 and out through the
first major surface 22 to be incident on the first optical adjuster
region 52, which transmits the light. The light transmitted by the
optical adjuster region 52 is modified by the optical
characteristic thereof. Similarly, light output from the second
light output region 30 of second major surface 24 and incident on
the second optical adjuster region 68 exits the lighting assembly
10 in a direction away from the second major surface 24 as
indicated by arrow 74. As indicated by arrow 76, light output from
the second light output region 30 of the first major surface 22 of
light guide 20 is incident on the second optical adjuster region 54
that reflects the light back through the second major surface 22,
through the light guide 20 and out through the second major surface
24 to be incident on the second optical adjuster region 68, which
transmits the light. The light transmitted by the optical adjuster
region 68 is modified by the optical characteristic thereof. In
this embodiment, the direction (e.g., as indicated by arrows 70, 72
or by arrows 74, 76) in which light is emitted by the lighting
assembly 10 is controlled by the relative positioning of the light
source 18 and the light guide 20.
[0052] With additional reference to FIGS. 13-20, schematically
illustrated is another embodiment of part of the lighting assembly
10 having an adjustable light output. In this embodiment, a light
guide assembly 78 includes a first light guide 80 and a second
light guide 82. Additional light guides that are stacked with the
light guides 80, 82 may be present. The light guides 80 and 82 have
respective inner major surfaces 84 and 86 that are juxtaposed and
conform in surface contour to one another, but the major surfaces
84, 86 are separated by a gap sufficient to prevent the disruption
of total internal reflection within each light guide. Although the
light guides 80, 82 are illustrated as being similar in shape, the
light guides 80, 82 may differ in one or more of length, width and
thickness.
[0053] Referring additionally to FIGS. 14-20, similar to the
previous embodiments, the light source 18 and the light guide
assembly 78 are variably positionable relative to each other. In
the examples shown, the light source 18 is positioned so that more
of the light from the light source 18 is input into the first light
guide 80 through the light input edge 88 thereof than is input into
the second light guide 82 through the light input edge 90 thereof
(FIGS. 14 and 18), or more of the light is input into the second
light guide 82 through the light input edge 90 thereof than is
input into the first light guide 80 through a light input edge 88
thereof (FIGS. 16 and 20), or the light is apportioned between the
first light guide 80 and the second light guide 82 by inputting
light through the both light input edges 88 and 90 (FIGS. 15 and
19, showing apportionment that is approximately equal between the
two light guides 80 and 82).
[0054] In this embodiment, the first light guide 80 outputs light
with a first characteristic and the second light guide 82 outputs
light with a second characteristic, which is different than the
first characteristic. Exemplary characteristics of the output light
are identified above. In the embodiments of FIGS. 13-17, the
relative positioning of the light source 18 with respect to the
light guide assembly 78 varies in a direction parallel to the light
input edges 88, 90 and orthogonal to major surfaces of light guides
80, 82. The relative positioning of the light source 18 and the
light guides 80, 82 can additionally vary in a direction parallel
to the light input edges 88, 90 and parallel to the major surfaces
84, 86 of the light guides 80, 82 to provide additional light
output characteristics using, for example, the embodiments of FIGS.
3-12.
[0055] In one embodiment, the characteristic of the light output
from the lighting assembly is light output direction. For example,
with reference to FIGS. 14-16, depending on the relative
positioning of the light source 18 and the light guide assembly 78,
more light is output from the outer major surface 92 of the first
light guide 80 than is output from the outer major surface 94 of
the second light guide 82 (FIG. 14); more light is output from the
outer major surface 94 of the second light guide 82 than is output
from the outer major surface 92 of the first light guide 80 (FIG.
16); or similar amounts of light are output from both the outer
major surface 92 of the first light guide 80 and the outer major
surface 94 of the second light guide 82 (FIG. 15).
[0056] In some examples of the embodiment shown in FIGS. 14-16,
light extracting elements 27 of the light guides 80, 82 are
configured so that light entering the light input edge 88 exits the
first light guide 80 through the outer major surface 92 and so that
light entering the light input edge 90 exits the second light guide
82 through the outer major surface 94. In other examples, light
extracting elements 27 of the light guides 80, 82 are configured so
that light entering the light input edge 88 exits the second light
guide 82 through the outer major surface 94 and so that light
entering the light input edge 90 exits the first light guide 80
through the outer major surface 92. As shown in FIG. 17, light
extracting elements 27 of the light guides 80, 82 are configured so
that light entering the light input edge 88 of the first light
guide 80 exits the first light guide 80 through the inner major
surface 84, enters the second light guide 82 through the inner
major surface 86, passes through the second light guide 82 and
exits through the outer major surface 94 of the second light guide
82. Additionally, the light extracting elements 27 are configured
so that light entering the light input edge 90 of the second light
guide 82 exits the second light guide 82 through the inner major
surface 86, enters the first light guide 80 through the inner major
surface 84, passes through the first light guide 80 and exits
through the outer major surface 92 of the first light guide 80. In
this exemplary embodiment, the surfaces 84 and 86 have cooperating
light extracting elements 96 such that light extracted from one of
the light guides 80, 82 enters the other of the light guides at an
angle such that the light does not propagate within the other of
the light guides by total internal reflection. FIG. 17 shows an
example in which inner major surfaces 84, 86 are mating surfaces in
which protrusions from one of the surfaces are accommodated within
depressions in the other of the surfaces, and vice versa. In FIG.
17, as depicted by light ray 98, light that has entered the light
input edge 88 (FIG. 14) of the first light guide 80 travels by
total internal reflection through the first light guide 80.
Portions of the light incident on an exemplary light extracting
element 96 exits the first light guide 80 by refraction by the
light extracting element 96 and enters the second light guide 82
through an exemplary light extracting element 97. The light then
passes through the second light guide 82 and, when incident on the
outer major surface 94, exits the second light guide 82 by
refraction. Light entering the light guide assembly 78 through the
light input surface 90 of the second light guide 82 behaves
similarly, and exits the light guide assembly 78 through the outer
major surface 92 of the first light guide 80.
[0057] As another example, with reference to FIGS. 18-20, depending
on the relative positioning of the light source 18 and the light
guide assembly 78 to apportion light input between the light guides
80, 82, more light is output from the outer major surface 92 of the
first light guide 80 than from an edge 100 of the second light
guide 82 distal the light input edge 90 (FIG. 18), or more light is
output from the edge 100 of the second light guide 82 than from the
outer major surface 92 of the first light guide 80 (FIG. 20), or
similar amounts of light are output from both the major surface 92
of the first light guide 80 and the edge 100 of the second light
guide 82 (FIG. 19). Light extracting elements 27 at one or both of
the major surfaces 84, 92 of the first light guide 80 are
configured to output light through the outer major surface 92.
Also, in the example shown, the second light guide 82 does not have
light extracting elements 27 so that light propagates through the
light guide 82 until it is incident on the distal edge 100 and
exits the light guide 82 by refraction. The edge 100 may include an
anti-reflective coating to maximize light transmission through the
edge. In a variation, the second light guide 82 has light
extracting elements 27 configured so that a portion of the light
that propagates through the light guide 82 exits the outer major
surface 94 and another portion (typically the remainder) of the
light exits the edge 100.
[0058] With reference to all of the figures, a characteristic of
the light output of the lighting assembly 10 is modified based on
the variable relative positioning of the light source 18 and the
light guide 20 (or, in some embodiments, the variable relative
positioning of the light source 18 and the light guide assembly
78). The modification further depends on the optical
characteristics associated with each light output region of the
light guide 20 or light guide assembly 78. For example, the
relative positioning may be varied to selectively provide a light
output from the lighting assembly with a light ray angle
distribution that is a first light ray angle distribution, or a
second light ray angle distribution, different from the first light
ray angle distribution, or is any intermediate light ray angle
distribution between the first and second light ray angle
distributions.
[0059] The color of the light output by the lighting assembly 10
may be changed using a color filter layer on or as part of the
optical adjuster 46 in one or both regions 52, 54 thereof, or on or
as part of the light guide 20; a color filtering material
composition of the optical adjuster 46 in one or both regions 52,
54 thereof, or on or as part of the light guide 20; a dichroic
filter on or as part of the optical adjuster 46 in one or both
regions 52, 54 thereof, or on or as part of the light guide 20; or
a wavelength shifting material on or as part of the optical
adjuster 46 in one or both regions 52, 54 thereof, or on or as part
of the light guide 20. In one example, the lighting assembly 10 is
configured to change color temperature of the light output. Many
LED light sources 18 emit light in an intended range of wavelengths
to achieve a corresponding color temperature. However, within
batches of LEDs having the same nominal color temperature, there is
variation from LED to LED. Also, sometimes broad-spectrum LEDs
(e.g., "white light" LEDs) or groups of tri-color LEDs (e.g., a red
LED, a blue LED and a green LED whose outputs combine to produce
white light) do not produce a color temperature that is desirable
to a user or appropriate for a certain lighting application. To
modify the color temperature of the light output from the lighting
assembly 10, an optical characteristic associated with the first
region 28, and possibly with the second region 30, may be used. For
instance, the optical characteristic associated with the first
region 28 may modify the light output to be warmer (either or both
of more red and less blue) and the optical characteristic
associated with second region 30 may modify the light output to be
cooler (either or both of more blue and less red).
[0060] Some embodiments are configured to allow a user to adjust
the color temperature of light output from the lighting assembly 10
in order to achieve a desired color temperature. Other embodiments
are configured to allow a manufacturer of the lighting assembly 10
to adjust the color temperature of light output from the lighting
assembly 10 to compensate for different color temperatures
associated with different lots of light sources 18. This allows the
lighting assembly manufacturer to source a broader range of light
sources 18 from one or more suppliers and still manufacture
lighting assemblies with a defined, consistent color
temperature.
[0061] In some embodiments, the relative positioning of the light
guide 20 and the light source 18 is varied by the manufacturer of
the lighting assembly 10 until the output light has a defined
characteristic (e.g., a defined color temperature is obtained). The
relative positioning is then fixed by the manufacturer of the
lighting assembly 10 and the lighting assembly 10 is configured in
a manner that minimizes the ability of a user of the lighting
assembly 10 to further vary the relative positioning. In other
embodiments, the user has the ability to vary the relative
positioning.
[0062] Other applications will be apparent based on using any
combination of the above-noted optical characteristics and
structural embodiments.
[0063] In yet another embodiment, the light source assembly 16
includes another light source that does or does not move relative
to the light guide 20. In this embodiment, the additional light
source is selectively illuminated to further change the location at
which the light is input to the light guide 20.
[0064] Returning to FIG. 1, additional details regarding the
lighting assembly 10 when embodied as the light bulb 12 will be
described. The light bulb 12 includes a base 102. The illustrated
base 102 is an Edison base, but other types of bases 102 may be
used, including any commercially-standard base or proprietary base
used for mechanically securing an incandescent bulb, a fluorescent
bulb, a compact fluorescent bulb (CFL), a halogen bulb, a high
intensity discharge (HID) bulb, an arc lamp, or any other type of
bulb into a lamp, a lighting fixture, a flashlight, a socket, etc.,
and/or for supplying electricity thereto. The bulb 12 typically
further includes a heat sink 104 that dissipates heat generated by
the light sources 18. The heat sink 104 of the illustrated
embodiment forms part of the housing 36. Parts of the light bulb
12, such as the light guide 20 and the light source 18, are
described above with reference to FIGS. 3-20.
[0065] References herein to a "light bulb" are meant to broadly
encompass light-producing devices that fit into and engage any of
various fixtures for mechanically mounting the light-producing
device and for providing electrical power thereto. Examples of such
fixtures include, without limitation, screw-in fixtures for
engaging an Edison light bulb base, a bayonet fixture for engaging
a bayonet light bulb base, or a bi-pin fixture for engaging a
bi-pin light bulb base. Thus the term "light bulb," by itself, does
not provide any limitation on the shape of the light-producing
device, or the mechanism by which light is produced from electric
power. Also, the light bulb need not have an enclosed envelope
forming an environment for light generation. The light bulb may
conform to American National Standards Institute (ANSI) or other
standards for electric lamps, but the light bulb does not
necessarily have to have this conformance.
[0066] Returning to FIG. 2, additional details regarding the
lighting fixture 14 will be described. The lighting fixture 14 may
be a hanging light (as shown), a ceiling light (e.g., an assembly
to fit in a drop-down ceiling or secure flush to a ceiling), a wall
sconce, a table lamp, a task light, or any other illumination
device. The lighting fixture includes a housing 106 for retaining
the light source assembly 16 and the light guide 20. The housing
106 may retain or may serve as a heat sink. In some embodiments,
the lighting fixture 14 includes a mechanism 108 (e.g., a chain or
wire in the case of a hanging light, clips or fasteners in the case
of a ceiling light or wall sconce, etc.) to mechanically secure the
lighting assembly to a retaining structure (e.g., a ceiling, a
wall, etc.). In other embodiments, the mechanism 108 is a stand
and/or base assembly to allow the lighting fixture 14 to function
as a floor lamp, table lamp, task lamp, etc. Electrical power is
supplied to the lighting fixture through appropriate conductors,
which in some cases may form part of or pass through the mechanism
108. Parts of the light bulb 12, such as the light guide 20 and the
light source 18, are described above with reference to FIGS.
3-20.
[0067] Referring now to FIGS. 21-23, another embodiment of a
lighting assembly 10 is illustrated. In this embodiment, the
illustrated lighting assembly 10 is a light bulb 12. The light bulb
12 has a base 102 that is configured to mechanically mount the
light bulb 12 to a compatible socket (not shown) and receive
electrical power from the socket. The light bulb 12 also includes a
housing 36 that is mechanically coupled to the base 102. In one
embodiment, the housing 36 also serves as a heat sink or retains a
heat sink for dissipating heat.
[0068] One or more light sources 18 are mechanically coupled to the
housing 36. The light sources 18 are arranged to coordinate with
one or more light guides 20 and one or more optical adjusters 110
as described in greater detail below. In one embodiment, and for
the purpose of the coordination with the light guides 20 and the
optical adjusters 110, the individual light sources 18 are grouped
into a number of light source groups 103. In some embodiments, no
more than a respective single light source 18 constitutes each
light source group 103. In one embodiment, the light sources 18 are
mounted to a printed circuit board 19 (not shown in FIGS. 21-23,
but see FIG. 1) that is attached to the housing 36. Electrical
circuitry (not shown) to drive the light sources 18 using
electricity received through the base 102 is located in the base
102 or the housing 36. Therefore, the light sources 18 are
electrically coupled to the base 102.
[0069] The light bulb 12 includes one or more light guides 20 that
are mechanically coupled to the housing 36 and are variably
positionable relative to the light sources 18 by an adjustment
member 112 that is rotatable relative to the housing 36. Similar to
the light guides described above, each light guide 20 includes
opposed major surfaces 22, 24 between which light propagates by
total internal reflection, a light input edge 26, and light
extracting elements 27 (not specifically shown in FIGS. 21-23) at
at least one of the major surfaces 22, 24.
[0070] The light guides 20 each are positionable between a first
position and a second position. In the example shown in FIGS. 21
and 22, each light guide 20 is in the second position. When a light
guide 20 is in its first position, the light input edge 26 is
adjacent and aligned with one of the light source groups 103 such
that the light guide 20 is edge lit by the light sources 18 of the
light source group 103. When the light guide 20 is in its second
position, the light input edge 26 is not adjacent and not aligned
with any of the light sources 18. Thus, when the light guide 20 is
in the second position, the light guide 20 is not edge lit by light
emitted from any of the light sources 18. Light guide 20 will be
regarded as not being edge lit by any of the light sources 18 in
positions of the light guide 20 in which the light extracted from
the light guide 20 has an intensity less than one-tenth of the
light extracted from the light guide 20 when the light guide 20 is
in the first position.
[0071] In one embodiment, the light extracting elements 27 are
configured to extract light from the light guide 20 with a diffuse
light ray angle distribution. Therefore, when the light guide 20 is
in the first position, the light extracted from the light bulb 12
will illuminate a wide area. In some embodiments, the light guide
20 has a secondary optical characteristic to affect the light
extracted from the light guide 20. Exemplary secondary optical
characteristics include reflective, light redirecting (such as by
the addition of a light-redirecting film (not shown) adjacent at
least one of the major surfaces 22, 24), polarizing, wavelength
shifting and color attenuating. In some embodiments, the light
guide 20 has more than one secondary optical characteristic to
affect the light extracted from the light guide. In other
embodiments, different ones of the light guides 20 respectively
affect light with different secondary optical characteristics.
[0072] The light bulb 12 of FIGS. 21-23 further includes one or
more optical adjusters 110. In one embodiment, there is a group of
optical adjusters (referred to as optical adjuster group 111) for
each light source group 103 and, within each optical adjuster group
111, there is an optical adjuster 110 for each light source 18. In
some embodiments, no more than a respective single optical adjuster
110 constitutes each optical adjuster group 111. The optical
adjusters 110 are mechanically coupled to the housing 36 by the
adjustment member 112 that is rotatable to variably position the
optical adjusters 110 relative to the light sources 18. In one
embodiment, when the one or more light guides 20 are in the second
position, the optical adjuster groups 111 are aligned with
respective light source groups 103 so that each optical adjuster
110 is respectively aligned with at least one of the light sources
18. In this manner, light emitted from the light sources 18 is
emitted from the light bulb 12 through respective optical adjusters
110.
[0073] In one embodiment, the optical adjusters 110 are lenses. One
type of lens for the optical adjusters 110 is a collimating lens
configured so that when light is emitted from the light bulb 12
through the collimating lenses, the light is emitted with a
narrower light ray angle distribution than when light is emitted
from the light bulb 12 through the light guide 20. In other
embodiments, the optical adjusters 110 impart a different
characteristic or a secondary characteristic to the light.
Exemplary optical characteristics of the optical adjusters 110
include specularly transmissive, diffusive, light redirecting,
polarizing, intensity reducing, wavelength shifting and color
attenuating. In some embodiments, the optical adjusters 110 have
more than one optical characteristic that affects the light emitted
from the light bulb 12. In other embodiments, different ones of the
optical adjusters 110 respectively affect light with different
optical characteristics.
[0074] The light guides 20 and the optical adjusters 110 of the
illustrated embodiment are mechanically coupled to the adjustment
member 112. The adjustment member 112 is, in turn, mechanically
coupled to the housing 36. The adjustment member 112 is variably
positionable relative to the housing 36 to move each light guide 20
between its first and second positions and, correspondingly, move
each optical adjuster group 111 into alignment with the respective
light source group 103 when the light guide 20 is in the second
position. In the illustrated embodiment, the light sources 18 are
arranged along the circumference of a circle in a plane normal to a
longitudinal axis of the light bulb 12. The adjustment member 112
rotates about the longitudinal axis of the light bulb 12. The light
guides 20 and the optical adjusters 110 are retained by the
adjustment member 112 so that the light input edges 26 of the light
guides 20 and the optical adjusters 110 are arranged along the
circumference of the above-described circle in a plane parallel to
and adjacent the plane of the light sources 18. In the example
shown, for alignment of the light input edges 26 with the light
sources 18, the light guides 20 are curved in the length direction
of the light input edges 26. Other layouts of the light sources 18,
light input edges 26, and optical adjusters 110 other than circular
arrangements are possible. In another example, the light guides 20
have non-curved light input edges 26 and the light sources 18 are
arranged along one or more straight lines. In another example, the
light guides 20 are non-parallel to the axis of rotation of the
adjustment member 112.
[0075] In one embodiment, an example of which is shown in FIG. 23,
the adjustment member 112 is a disk-like member and has a first set
of openings 114. Each opening 114 has a respective light guide 20
retained therein in a manner that exposes the light input edge 26
to the light sources 18. The adjustment member 112 also has a
second set of openings 116 and each opening 116 has a respective
optical adjuster 110 retained therein in a manner that exposes the
optical adjuster 110 to the light sources 18. In an example, the
light guides 20 and the optical adjusters 110 are retained in the
openings 114, 116 by an adhesive. Other ways of mounting the light
guides 20 and the optical adjusters 110 to the adjustment member
112 are possible and may be used. In another example, the optical
adjuster is transparent and lacks the openings 114, 116 (e.g., the
light guides 20 and the optical adjusters 110 are mounted to or are
part of the transparent adjustment member 112).
[0076] In the illustrated embodiment, the housing 36 includes
cooling air vents 118 through which air flows to dissipate heat
generated by the light sources 118. The cooling air vents 118 allow
air to pass from the outside of the housing 36 adjacent the base
102 to a region surrounded by the light guides 20, or vice versa,
depending on the orientation of the bulb 12. To allow air to flow
into or out of the cooling air vents 118, the adjustment member 112
includes a third set of openings 120. The third set of openings 120
of the illustrated embodiment align with the air flow vents 118
when the adjustment member 112 is positioned to place the light
guides 20 in either of the first position or the second position.
Also, the openings 120 of the third set and the cooling air vents
118 are configured to allow air flow through the openings 120 and
the cooling air vents 118 when the adjustment member 112 is in
other positions between the first and second positions.
[0077] In one embodiment, the adjustment member 112 has increased
resistance to movement when positioned so that the light guides 20
are in the first and second positions relative to when the
adjustment member 112 is in other positions (e.g., the light guides
20 are not in one of the first or second positions). In this
manner, light bulb 12 will have a tendency to stay in the
configurations in which the light guides 20 are positioned to be
edge lit by the light sources 18 or the optical adjusters 110 are
positioned to receive light from respective light sources 18. Other
positions of the adjustment member 112 also may have increased
resistance to movement, such as when some of the optical adjusters
110 are positioned to receive light from some of the light sources
18 (e.g., the optical adjuster groups 111 partially overlap with
respective light source groups 103) and the remaining light sources
18 of the light source groups 103 edge light the light guides 20
(e.g., the light input edges 26 partially overlap with respective
light source groups 103). In an example, one of the housing 36 and
the adjustment member 112 includes a detent (not shown) and the
other of the housing 36 and the adjustment member 112 includes an
indent (not shown) that collectively provide the resistance to
movement in certain positions of the adjustment member 112.
[0078] When some of the optical adjusters 110 are positioned to
receive light from some of the light sources 18 and the remaining
light sources 18 edge light the light guides 20, the light ray
angle distribution of light emitted from the light bulb 12 is a
combination of the light ray angle distribution of the light
extracted from the light guides 20 and the light ray angle
distribution of the light emitted by the optical adjusters 110.
Also, the variable relative positioning of the adjustment mechanism
112 and the light sources 18 allows for selectively apportioning
light that is output from the light bulb 12 between the light that
is output by way of the light guides 20 and the light that is
output by way of the optical adjusters 110.
[0079] In this disclosure, the phrase "one of" followed by a list
is intended to mean the elements of the list in the alterative. For
example, "one of A, B and C" means A or B or C. The phrase "at
least one of" followed by a list is intended to mean one or more of
the elements of the list in the alterative. For example, "at least
one of A, B and C" means A or B or C or (A and B) or (A and C) or
(B and C) or (A and B and C).
* * * * *