U.S. patent application number 15/940827 was filed with the patent office on 2018-10-04 for apparatus for controlling the re-distribution of light emitted from a light-emitting diode.
The applicant listed for this patent is Korry Electronics Co.. Invention is credited to John R. Green, Stephen H. Humphrey, Timothy R. Robinson.
Application Number | 20180283650 15/940827 |
Document ID | / |
Family ID | 47390512 |
Filed Date | 2018-10-04 |
United States Patent
Application |
20180283650 |
Kind Code |
A1 |
Green; John R. ; et
al. |
October 4, 2018 |
APPARATUS FOR CONTROLLING THE RE-DISTRIBUTION OF LIGHT EMITTED FROM
A LIGHT-EMITTING DIODE
Abstract
A system for re-distributing light emitted from a light source
using an optical element is described. The optical element is
manufactured using a bulk matrix material, and diffusing particles
and/or scattering particles are embedded within the bulk material.
The optical element is coupled to the light source to capture
emitted light and redistribute the light in a desired angular
distribution pattern depending on the ratio of total weight of
diffusing particles to total weight of scattering particles.
Inventors: |
Green; John R.; (Everett,
WA) ; Humphrey; Stephen H.; (Everett, WA) ;
Robinson; Timothy R.; (Everett, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Korry Electronics Co. |
Everett |
WA |
US |
|
|
Family ID: |
47390512 |
Appl. No.: |
15/940827 |
Filed: |
March 29, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15074747 |
Mar 18, 2016 |
9964280 |
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15940827 |
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13172617 |
Jun 29, 2011 |
9322515 |
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15074747 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V 3/049 20130101;
F21V 3/02 20130101; H05K 999/99 20130101; F21V 29/89 20150115; F21Y
2115/10 20160801; G02B 5/0242 20130101; G02B 5/0278 20130101; F21K
9/20 20160801; F21V 29/70 20150115; G02B 5/0294 20130101; F21V 5/00
20130101; F21V 19/0055 20130101 |
International
Class: |
F21V 3/04 20060101
F21V003/04; F21V 3/02 20060101 F21V003/02; F21V 29/70 20060101
F21V029/70 |
Claims
1. A system, comprising: a source configured to emit
electromagnetic radiation having a first angular distribution
pattern; an optical element coupled to the source, wherein the
optical element is formed from a bulk material, and the bulk
material is embedded with a first type of particle, and further
wherein the optical element has a shape that captures the first
angular distribution pattern and emits a second angular
distribution pattern.
2. The system of claim 1, wherein the bulk material is further
embedded with a second type of particle.
3. The system of claim 2, wherein the first type of particle is one
or more type of scattering particles, and the second type of
particle is one or more type of diffusing particles.
4. The system of claim 1, wherein the first angular distribution
pattern does not emit radiation beyond a 180.degree. arc in a plane
passing through a center of and normal to the source, and further
wherein the second angular distribution pattern emits radiation
over at least a 180.degree. arc in the plane passing through the
center of and normal to the source.
5. The system of claim 1, wherein the optical element is remote
from the source.
6. The system of claim 1, wherein the optical element has a size
and a shape substantially similar to a rounded portion of an A19
incandescent light bulb.
7. A system, comprising: a light-emitting element; an optical
element coupled to the light emitting element, wherein the optical
element is formed from a bulk material, the bulk material is
embedded with a first type of particle, and further wherein the
optical element captures the light emitted by the light emitting
element and re-emits the light in a quasi-isotropic distribution
pattern.
8. The system of claim 7, wherein the bulk material is further
embedded with a second type of particle.
9. The system of claim 8, wherein the first type of particle is a
scattering particle, and the second type of particle is a diffusing
particle.
10. The system of claim 7, wherein the optical element is coupled
to the light emitting element with a material having a refractive
index that substantially matches a refractive index of the bulk
material.
11. The system of claim 7, wherein the optical element is
spherical.
12. The system of claim 11, wherein a diameter of the spherical
optical element is greater than a width of a base supporting the
light emitting element.
13. The system of claim 7, wherein the light emitting element is a
light emitting diode.
14. The system of claim 7, wherein the light emitting element is a
laser.
15. The system of claim 7, wherein the quasi-isotropic distribution
pattern has a light distribution uniformity between 0.6 and 1.4,
and further wherein the light distribution uniformity is given by
U= U = .intg. - 110 .degree. - 130 .degree. Id .theta. + .intg. 110
.degree. 130 .degree. Id .theta. 2 .intg. - 10 .degree. 10 .degree.
Id .theta. , ##EQU00003## wherein I corresponds to emitted
intensity in a given direction.
16. A method of simulating a light emission distribution of an
incandescent light bulb, comprising: generating light with a
light-emitting diode (LED), wherein the LED only emits light in a
forward direction; capturing the generated light with an optical
element, wherein the optical element is embedded with a first type
of particle; re-emitting at least some of the captured light in a
distribution pattern, wherein the distribution pattern includes
emission in a backward direction.
17. The method of claim 16, wherein the optical element is further
embedded with a second type of particle.
18. The method of claim 17, wherein the first type of particle is a
scattering particle, and the second type of particle is a diffusing
particle.
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/074,747 filed Mar. 18, 2016 and titled
APPARATUS FOR CONTROLLING THE RE-DISTRIBUTION OF LIGHT EMITTED FROM
A LIGHT-EMITTING DIODE, which is a continuation of U.S. patent
application Ser. No. 13/172,617 filed Jun. 29, 2011 and titled
APPARATUS FOR CONTROLLING THE RE-DISTRIBUTION OF LIGHT EMITTED FROM
A LIGHT-EMITTING DIODE, both of which are incorporated herein by
reference in their entirety.
BACKGROUND
[0002] Solid-state light emitting diodes (LEDs) have greatly
improved over the last several years. In fact, LEDs outperform the
A19 incandescent light bulb in terms of lifetime and efficiency. As
a result, LEDs are candidates for replacing the commonly used, yet
inefficient, incandescent light bulbs for general lighting
applications. However, surface-mount LEDs emit light in a
substantially Lambertian pattern which is much more directional
than the quasi-isotropic light emitted from an incandescent light
bulb.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Examples of an apparatus for redistributing light emitted
from a source are illustrated in the figures. The examples and
figures are illustrative rather than limiting.
[0004] FIG. 1A shows a typical spatial distribution of the emission
from a light-emitting diode (LED).
[0005] FIG. 1B shows a typical spatial distribution of the emission
from an incandescent light bulb.
[0006] FIGS. 2A-2D show different views of an example LED-based
lamp assembly that uses an optical element to angularly
redistribute the light emitted by the LED.
[0007] FIG. 3 shows an example distribution pattern of light
re-emitted from an LED coupled to a spherical optical element
containing two different types of suspended particles.
[0008] FIG. 4 shows three example distributions of re-emitted light
from an optical element having embedded diffusing and scattering
particles and coupled to an LED.
[0009] FIG. 5 shows a graph of light distribution uniformity as a
function of concentration of diffusing particles and scattering
particles.
[0010] FIG. 6 shows a stacked area plot of the measured light
transmitted through a sample of bulk matrix material and the
reflected light from the sample.
[0011] FIG. 7 is a flow diagram illustrating an example process of
redistributing light emitted from a source.
[0012] FIG. 8 shows an example block diagram of components of a
lighting apparatus that has an optical element used to redistribute
light emitted from a light source.
[0013] FIG. 9 shows a plot of transmission as a function of
concentration for diffusing particles and for scattering
particles.
DETAILED DESCRIPTION
[0014] An apparatus is described for capturing the light emitted
from a light source and redistributing the light in a different
emission pattern from that of the light source. The apparatus is
made from a bulk matrix material that can have two different types
of particles embedded within the material, diffusing particles and
scattering particles. By varying the concentrations of the two
types of particles, the angular emission of the redistributed light
can be tuned. In one embodiment, the Lambertian emission from a
light emitting diode (LED) is angularly redistributed to simulate
the emission from a typical incandescent light bulb.
[0015] Various aspects and examples of the invention will now be
described. The following description provides specific details for
a thorough understanding and enabling description of these
examples. One skilled in the art will understand, however, that the
invention may be practiced without many of these details.
Additionally, some well-known structures or functions may not be
shown or described in detail, so as to avoid unnecessarily
obscuring the relevant description.
[0016] The terminology used in the description presented below is
intended to be interpreted in its broadest reasonable manner, even
though it is being used in conjunction with a detailed description
of certain specific examples of the technology. Certain terms may
even be emphasized below; however, any terminology intended to be
interpreted in any restricted manner will be overtly and
specifically defined as such in this Detailed Description
section.
[0017] A surface mount LED is typically used in lighting
applications and emits light in a Lambertian pattern. The intensity
of the emitted Lambertian light is given by the equation: I=I.sub.0
cos(.theta.), where I.sub.0 the intensity emitted in a forward
direction normal to the light source, and .theta. is the
observation angle. FIG. 1A shows a cross-section of a normalized
angular light distribution pattern from a surface mount LED. The
distribution pattern is rotationally symmetric about the line
corresponding to .theta.=0.degree.. In the forward direction above
the LED at .theta.=0 the LED emits a maximum amount of light, and
towards the sides of the LED at .theta.=90.degree. and 270.degree.,
no light is emitted. Further, no light is emitted behind the LED,
where .theta. is less than 270.degree. and greater than
90.degree..
[0018] In contrast, a standard A19 incandescent light bulb emits
light having a quasi-isotropic distribution. A cross-section of a
normalized distribution is shown in FIG. 1B. The incandescent bulb
emits a substantial amount of light in a forward direction above
the light bulb at .theta.=0 and a maximum amount of light towards
the sides at .theta.=90.degree. and 270.degree.. The incandescent
bulb emits light towards the underside of the bulb as well, for
example at .theta.=135.degree. and 225.degree.. Thus, an
incandescent bulb emits light in a "quasi-isotropic" pattern.
[0019] While an LED has many advantageous qualities such as higher
efficiency and a longer lifetime than an incandescent bulb, the
directional light emission from an LED is noticeably different and
would not be a suitable replacement for the incandescent bulb. For
example, if an LED lamp were used in a table top light fixture, the
light would be directed towards the ceiling and not towards a work
surface situated below the light. Some of the embodiments of the
apparatus presented below redistribute the light from an LED to
imitate the quasi-isotropic distribution of light emitted from an
incandescent bulb.
[0020] FIGS. 2A-2D show an example embodiment of an LED-based
lighting assembly that redistributes the light emitted from one or
more LEDs. The light emitted by the one or more LEDs can be in the
visible spectrum. Additionally or alternatively, the light can be
comprised of wavelengths that are not visible. FIG. 2A shows a side
view of the example lamp assembly having a heat sink 210 for
dissipating heat generated by the LED(s) and an optical element 205
coupled to the heat sink. The heat sink is made from a thermally
conductive material such as aluminum. In this embodiment, the
optical element 205 has been formed in a spherical shape having a
diameter equal to the diameter of the spherical section of an A19
incandescent bulb to simulate the appearance and function of the
incandescent bulb.
[0021] FIG. 2B shows a perspective view of the example lighting
assembly with the heat sink 210 cut away to show that the optical
element 205 is coupled to the heat sink through an LED holder 215.
Also, FIG. 2B shows that the electronics 220 used for driving the
LED are housed within the heat sink 210.
[0022] FIG. 2C shows a view of an example optical element 205 and
the LED holder 215 without the heat sink 210 attached. FIG. 2D
shows the example LED holder 215 detached from the optical element
205. The LED holder 215 is made from a thermally conductive
material such as aluminum. Inside the LED holder 215 is the light
source 225. The light source 225 can be, but is not limited to, a
single LED, multiple LEDs placed in any configuration, or other
light source technologies emitting light into a half-space. Such
light sources may include, for example, LEDs, organic LEDs,
electroluminescent sources, or lasers. In one embodiment, if the
light source 225 is one or more LEDs, the LEDs can further be
coated with an encapsulant containing phosphor(s) to generate light
in a certain band of wavelengths. In one embodiment, the light
source 225 is seated in a ceramic base 220. In one embodiment, the
LED holder 215 is attached to the optical element 205 using screws
that are placed in the through holes 230 in the LED holder.
[0023] The optical element 205 is made from a bulk matrix material
such as a polymer, glass, crystal, or foam. The bulk matrix
material is further embedded with a combination of two types of
particles, a light diffusing particle and a light scattering
particle. A light diffusing particle is a particle that generally
redirects light in the forward direction, while a light scattering
particle is a particle that generally redirects light in the
backward direction with negligible light absorption. FIG. 9 shows a
plot of two curves of transmission as a function of concentration
for light diffusing particles (solid line 910) and for light
scattering particles (solid line with circles 920). Because a light
diffusing particle redirects light in the forward direction, the
total transmission (measured, for example, with an integrating
sphere) of a bulk material embedded with light diffusing particles
remains fairly constant with increasing concentration of particles.
In contrast, the transmission of a bulk material embedded with
light scattering particles is sensitive to the concentration of the
particles. In one embodiment, a light scattering particle can be
defined as a particle that causes more than a 10% decrease in
transmission with a corresponding increase in reflection for a
five-fold increase in concentration of the particle. For example,
air bubbles can act as scattering particles in the bulk matrix
material foam.
[0024] In general, the diffusing particles have a refractive index
that is close to the refractive index of the bulk matrix material,
while the difference between the refractive index of the scattering
particles and the refractive index of the bulk matrix material is
larger than the difference between the refractive index of the
diffusing particles and the refractive index of the bulk matrix
material As a result, the diffusing particles diffuse the light
that strikes the particles, essentially redirecting the light in a
different but generally forward direction with negligible back
scatter. In contrast, the scattering particles scatter light
impinging on the particles in a generally backward direction. By
using a combination of the two types of particles in a bulk matrix
material, the light distribution can be controlled better and is
less susceptible to variations in concentration of the particles.
However, in some embodiments, only diffusing particles or only
scattering particles are used in a bulk matrix material to
redistribute light.
[0025] FIG. 3 shows an example spatial distribution of light
re-emitted from an LED coupled to a spherical optical element 205
containing two different types of suspended particles. A spherical
shape having a diameter of 60 mm was selected for the optical
element to simulate the shape of the rounded portion of the A19
incandescent bulb. The ratio of the concentrations of the two types
of particles present in the bulk matrix material controls the light
distribution. The bulk matrix material for the sphere used to
generate the light distribution shown in the example of FIG. 3 is a
polymer having an index of refraction of 1.51. The diffusing
particles embedded in the bulk matrix material have a bulk
refractive index of 1.58 at a concentration of 3.75 parts per
thousand (ppt) by weight with an average particle size of 8
microns, and the scattering particles embedded in the bulk matrix
material have a bulk refractive index of 2.2 at a concentration of
0.06 ppt by weight with an average particle size of 0.25 microns.
In one embodiment, the bulk matrix material is urethane, the
diffusing particles are a styrenic polymer, and the scattering
particles are titanium dioxide.
[0026] By changing the ratio of diffusing particles concentration
(i.e., forward scattering particles) to (backward) scattering
particles concentration, the angular distribution of light can be
tuned. FIG. 4 shows three example distributions of light 410, 420,
430. The light emitted in the forward direction (.theta.=0) for
each of the light distributions 410, 420, 430 has been normalized
to one to enable a comparison of the distributions. The relative
amounts of light emitted to the sides and behind the light source
are dependent upon the ratio of the diffusing particles
concentration to the scattering particles concentrations. For light
distribution 410, the ratio is 90:1 for light distribution 420, the
ratio is 135:1; and for light distribution 430, the ratio is
70:1.
[0027] One metric of isotropic fidelity of the lighting apparatus
with the optical element is the ratio of light emitted in a
backward direction to light emitted in a forward direction. The
forward direction is selected to be the direction normal to the
plane of the LED die surface, that is, the direction in which the
maximum amount of light is emitted from an unmodified LED. In an
LED system, the emission in the backward direction tends to
decrease monotonically, and the amount of light emitted sharply
decreases as the backward angle approaches 180.degree. from the
normal (i.e., a direction opposite from the normal direction). It
has been determined empirically that if the light at 120.degree.
from the forward normal axis has the same intensity as the normal
axis (0.degree.), the light distribution has a high degree of
uniformity in all directions. As a result, the metric for light
distribution uniformity, U, has been selected to be defined by:
U = .intg. - 110 .degree. - 130 .degree. I d .theta. + .intg. 110
.degree. 130 .degree. I d .theta. 2 .intg. - 10 .degree. 10
.degree. I d .theta. . ( 1 ) ##EQU00001##
Thus, the light distribution uniformity is the integral of the
intensity of light emitted at -120.degree. and 120.degree. from the
forward normal axis over a 20-degree angular span centered at
-120.degree. and 120.degree., respectively, divided by twice the
integral of the intensity of light emitted in the forward normal
direction over a 20-degree angular span centered around the forward
normal direction. A uniformity of 1.0 would represent a light
distribution that is isotropic between 0.degree. and
.+-.120.degree. from normal. For comparison, the light distribution
uniformity equals zero for a surface mount LED having a Lambertian
angular distribution, while the light distribution uniformity
equals 1.2 for an incandescent light bulb. In one embodiment, a
quasi-isotropic distribution of light is one that has light
distribution uniformity between 0.6 and 1.4.
[0028] Several spherical optical elements having a diameter of 60
mm with various concentrations of diffusing and scattering
particles were produced. Each of the spherical optical elements was
made from the same bulk matrix material and used the same types and
dimensions of diffusing particles and scattering particles as
discussed for the optical element used to produce the spatial light
distribution shown in FIG. 3 above. Table 1 shows the concentration
(ppt by weight) of diffusers and scatterers of the optical elements
and a corresponding light distribution uniformity value, U,
calculated from measured intensity values of the spheres. FIG. 5
shows the light distribution uniformity values, U, plotted as a
function of the concentration of scattering particles in the
optical element (shown on the x-axis) and the concentration of
diffusing particles (shown on the y-axis). By interpolating between
the light distribution uniformity values that were calculated for
these spheres when placed over a white LED, lines of equal light
distribution uniformity were determined and mapped in FIG. 5. The
five mapped lines in FIG. 5 correspond to U values of 0.4, 0.6,
0.8, 1.0, and 1.2. The data points labeled 510, 520, 530 in FIG. 5
correspond to the spatial distribution curves labeled 410, 420,
430, respectively, in FIG. 4 One of the data points along the
x-axis shows the uniformity value (0.21) for an optical sphere
having a concentration of 0.04 ppt by weight of scattering
particles and no diffusing particles.
TABLE-US-00001 TABLE 1 Diffusers Scatterers (ppt by (ppt by weight)
weight) U 3.74 2.43 0.67 0.00 0.00 0.21 3.76 2.45 0.44 3.75 2.44
0.88 3.74 2.43 0.21 1.87 1.21 0.46 5.60 3.64 0.72 8.20 5.33 1.04
6.54 4.25 0.58 11.20 7.28 0.94 6.17 4.01 1.13 3.73 2.42 0.30 10.00
6.50 1.33 0.99 0.64 0.81 6.99 4.54 0.46
[0029] Another metric of performance of the lighting apparatus with
the optical element is the transmission of the apparatus.
Transmission is defined as the ratio of total light emitted from
the lighting assembly with a light redistribution optical element
divided by the total light emitted from the light source by itself,
as shown in equation (2):
T = .intg. 0 .degree. 360 .degree. .intg. 0 .degree. 180 .degree. I
element + LED sin .theta. d .theta. d .PHI. .intg. 0 .degree. 360
.degree. .intg. 0 .degree. 180 .degree. I LED sin .theta. d .theta.
d .PHI. . ( 2 ) ##EQU00002##
FIG. 6 shows a stacked area plot of measurements of total
transmission and total reflection performed on a 1 mm thick coupon
of the same bulk material as used for the test spheres used to
obtain the light distribution data shown in FIGS. 4 and 5. The
coupon contained a concentration of 1.3 ppt by weight of titanium
dioxide scattering particles without any diffusing particles. Light
unaccounted for by transmission and reflection is depicted as
absorption in FIG. 6. As shown in FIG. 6, the total amount of light
lost through absorption in the visible wavelength spectrum is very
low so that any light not transmitted is scattered backwards.
Similar transmission and reflection measurements were obtained for
a coupon that contained only diffusing particles. The losses in the
visible wavelength range from the bulk matrix material and from the
embedded particles were so low that the transmission measurements
for the different spheres were nearly identical. When the optical
element spheres are coupled to the LED die with an index-matching
material having an index of refraction of 1.50, the transmission
from the optical spheres is approximately 98%.
[0030] While the optical element used to redistribute the light
emitted from an LED has been described above as having a spherical
shape, other shapes can also be used to produce a desired angular
light distribution.
[0031] The width of the chosen shape should be greater than the
base that supports the LED. When the width condition is satisfied,
the optical element reduces the amount of light redirected back
towards the LED base and provides an escape path away from the base
to provide illumination in a downward direction.
[0032] Additionally, while the light source discussed above has
been described as an LED that has a Lambertian emission, the
optical element can be used with an LED that has a different
emission pattern or any other type of light source, such as lensed
LEDs, organic LEDs, electroluminescent devices, field emission
devices, or lasers. In one embodiment, the light source can be
remote from the optical element. In one embodiment, the light
source can emit electromagnetic radiation, where the emitted
spectrum includes wavelengths in the electromagnetic spectrum where
a bulk matrix material and diffusing particles are available to
diffuse the emitted spectrum and scattering particles are available
to scatter the emitted spectrum.
[0033] In one embodiment, the optical element embedded with
diffusing particles and/or scattering particles can be used with a
light source to create a substantially uniformly emitting planar
surface. In another embodiment, the optical element can be used to
generate isotropic light or light having a specified light
distribution using a remote source, such as a laser.
[0034] FIG. 7 is a flow diagram illustrating an example process of
modifying the distribution of electromagnetic radiation emitted
from a source. At block 705, electromagnetic radiation is generated
by a source. In one embodiment, the source can be a light source
such as one or more LEDs or a laser, and the electromagnetic
radiation can include visible light and/or other wavelengths of the
electromagnetic spectrum.
[0035] Then at block 710, the generated electromagnetic radiation
is captured with an optical element. In one embodiment, the
generated light is captured with a spherical shaped optical element
made from a bulk matrix material as described above.
[0036] At block 715, the captured radiation is re-distributed and
emitted by the apparatus. In one embodiment, the captured radiation
is re-distributed by diffusing particles and/or scattering
particles embedded within the bulk matrix material of the optical
element.
[0037] FIG. 8 shows an example block diagram of a lighting
apparatus 800 that has an optical element 820 for redistributing
the light emitted by a light source 810. The lighting apparatus can
also include a power supply 830. The optical element 820 can
include diffusing particles 821 and/or scattering particles
822.
[0038] The light source 810 generates the light that is
redistributed by the optical element. Light sources that can be
used include one or more LEDs, lasers, etc. The power supply for
the light source can include, but is not limited to, a battery or
power from a wall outlet.
[0039] The optical element 820 is a bulk matrix material, such as a
polymer, glass, crystal, or foam. The optical element 820 can be
any shape or size, such as a sphere that has the dimensions of the
rounded portion of a typical incandescent light bulb. In one
embodiment, the optical element 820 can include diffusing particles
821 embedded within the bulk material. Additionally or
alternatively, the optical element 820 can include scattering
particles 822 embedded within the bulk material. In one embodiment,
the diffusing particles 821 and/or the scattering particles 822 are
substantially uniformly distributed throughout the optical element
820. In one embodiment, the diffusing particles 821 and/or the
scattering particles 822 can be distributed in particular
concentrations within the optical element 820 to provide a desired
angular redistribution of the light emitted by the light source
810.
Conclusion
[0040] Unless the context clearly requires otherwise, throughout
the description and the claims, the words "comprise," "comprising,"
and the like are to be construed in an inclusive sense (i.e., to
say, in the sense of "including, but not limited to"), as opposed
to an exclusive or exhaustive sense. As used herein, the terms
"connected," "coupled," or any variant thereof means any connection
or coupling, either direct or indirect, between two or more
elements. Such a coupling or connection between the elements can be
physical, logical, or a combination thereof. Additionally, the
words "herein," "above," "below," and words of similar import, when
used in this application, refer to this application as a whole and
not to any particular portions of this application. Where the
context permits, words in the above Detailed Description using the
singular or plural number may also include the plural or singular
number respectively. The word "or," in reference to a list of two
or more items, covers all of the following interpretations of the
word: any of the items in the list, all of the items in the list,
and any combination of the items in the list.
[0041] The above Detailed Description of examples of the invention
is not intended to be exhaustive or to limit the invention to the
precise form disclosed above. While specific examples for the
invention are described above for illustrative purposes, various
equivalent modifications are possible within the scope of the
invention, as those skilled in the relevant art will recognize. For
example, while spherical optical elements are discussed, optical
elements having any shape may be used under the principles
disclosed herein. While processes or blocks are presented in a
given order in this application, alternative implementations may
perform routines having steps performed in a different order, or
employ systems having blocks in a different order. Some processes
or blocks may be deleted, moved, added, subdivided, combined,
and/or modified to provide alternative or subcombinations. Also,
while processes or blocks are at times shown as being performed in
series, these processes or blocks may instead be performed or
implemented in parallel, or may be performed at different times.
Further any specific numbers noted herein are only examples. It is
understood that alternative implementations may employ differing
values or ranges.
[0042] The various illustrations and teachings provided herein can
also be applied to systems other than the system described above.
The elements and acts of the various examples described above can
be combined to provide further implementations of the
invention.
[0043] Any patents and applications and other references noted
above, including any that may be listed in accompanying filing
papers, are incorporated herein by reference. Aspects of the
invention can be modified, if necessary, to employ the systems,
functions, and concepts included in such references to provide
further implementations of the invention.
[0044] These and other changes can be made to the invention in
light of the above Detailed Description. While the above
description describes certain examples of the invention, and
describes the best mode contemplated, no matter how detailed the
above appears in text, the invention can be practiced in many ways.
Details of the system may vary considerably in its specific
implementation, while still being encompassed by the invention
disclosed herein. As noted above, particular terminology used when
describing certain features or aspects of the invention should not
be taken to imply that the terminology is being redefined herein to
be restricted to any specific characteristics, features, or aspects
of the invention with which that terminology is associated. In
general, the terms used in the following claims should not be
construed to limit the invention to the specific examples disclosed
in the specification, unless the above Detailed Description section
explicitly defines such terms. Accordingly, the actual scope of the
invention encompasses not only the disclosed examples, but also all
equivalent ways of practicing or implementing the invention under
the claims.
[0045] While certain aspects of the invention are presented below
in certain claim forms, the applicant contemplates the various
aspects of the invention in any number of claim forms. For example,
while only one aspect of the invention is recited as a
means-plus-function claim under 35 U.S.C. .sctn. 112, sixth
paragraph, other aspects may likewise be embodied as a
means-plus-function claim, or in other forms, such as being
embodied in a computer-readable medium. (Any claims intended to be
treated under 35 U.S.C. .sctn. 112, 6 will begin with the words
"means for.") Accordingly, the applicant reserves the right to add
additional claims after filing the application to pursue such
additional claim forms for other aspects of the invention.
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