U.S. patent application number 14/692550 was filed with the patent office on 2016-05-19 for wall wash luminaire with light guide and optical element therefore.
The applicant listed for this patent is Quarkstar LLC. Invention is credited to Victor E. Isbrucker, Ingo Speier.
Application Number | 20160139316 14/692550 |
Document ID | / |
Family ID | 55961490 |
Filed Date | 2016-05-19 |
United States Patent
Application |
20160139316 |
Kind Code |
A1 |
Speier; Ingo ; et
al. |
May 19, 2016 |
Wall Wash Luminaire With Light Guide and Optical Element
Therefore
Abstract
A light shaping article includes a solid optic having a
cross-sectional profile including an input interface; a convex
output surface opposite the input interface; a concave first side
surface extending between the input interface and the convex output
surface; and a second side surface opposite the concave first side
surface extending from between input interface to the convex output
surface. The concave first side surface and the convex output
surface are configured such that, when the solid optic receives
input light having an input angular range in a plane of the
cross-sectional profile, the solid optic guides the light to and
emits the light from the output surface in an output angular range
in the plane. A prevalent propagation direction of output light in
the output angular range is tilted toward the second side surface
relative to a prevalent propagation direction of input light in the
input angular range.
Inventors: |
Speier; Ingo; (Saanichton,
CA) ; Isbrucker; Victor E.; (Sturgeon Point,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Quarkstar LLC |
Las Vegas |
NV |
US |
|
|
Family ID: |
55961490 |
Appl. No.: |
14/692550 |
Filed: |
April 21, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62081482 |
Nov 18, 2014 |
|
|
|
Current U.S.
Class: |
362/607 ;
362/608 |
Current CPC
Class: |
G02B 6/0023 20130101;
G02B 6/0063 20130101; G02B 6/0086 20130101; F21V 14/04 20130101;
G02B 19/0066 20130101; F21V 7/00 20130101; G02B 6/0085 20130101;
G02F 2001/133607 20130101; F21S 8/06 20130101; G02B 6/003 20130101;
G02B 6/0068 20130101; F21S 8/036 20130101; G02B 27/0994 20130101;
G02B 6/0045 20130101; G02B 6/0073 20130101; G02B 19/0028 20130101;
F21V 21/26 20130101; G02B 6/0051 20130101; F21V 7/10 20130101; G02B
6/0011 20130101; F21S 8/026 20130101; F21Y 2115/10 20160801 |
International
Class: |
F21V 8/00 20060101
F21V008/00; F21V 7/10 20060101 F21V007/10; F21S 8/00 20060101
F21S008/00; F21V 21/26 20060101 F21V021/26 |
Claims
1. (canceled)
2. The illumination system of claim 30, wherein the second side
surface is planar.
3. The illumination system of claim 30, wherein the solid optic is
configured so that a divergence of output light in the output
angular range is smaller than a divergence of input light in the
input angular range.
4. The illumination system of claim 30, wherein the solid optic is
configured so that a relative tilt angle .alpha. between the
prevalent propagation direction of output light in the output
angular range and the prevalent propagation direction of input
light in the input angular range is in a tilt range of 3.degree. to
30.degree..
5. (canceled)
6. The illumination system of claim 30, wherein the concave first
side surface and the second side surface are shaped and arranged
relative to each other such that, for a given divergence of the
input angular range, the input light received by the solid optic
reaches the convex output surface either directly or via a single
reflection off the concave first side surface or the second side
surface.
7. The illumination system of claim 30, wherein the convex output
surface includes a diffusion pattern.
8. The illumination system of claim 30, further comprising a
diffusive film attached to the convex output surface.
9. The illumination system of claim 30, wherein the solid optic
comprises plastic material.
10. The illumination system of claim 30, wherein a separation
between the concave first side surface and the second side surface
at the input interface is less than 20 mm.
11. (canceled)
12. The illumination system of claim 30, wherein a separation
between the input interface and the convex output surface is less
than 50 mm.
13. The illumination system of claim 12, wherein the separation
between the input interface and the convex output surface is less
than 25 mm.
14. (canceled)
15. The illumination system of claim 30 further comprising one or
more optical couplers configured to collimate light emitted by the
LEEs and to provide the collimated light to the first end of the
light guide.
16. The illumination system of claim 30, wherein the LEEs are LEDs
that provide white light.
17. The illumination system of claim 30, wherein the lateral
surfaces of the light guide are planar and parallel.
18. The illumination system of claim 30, wherein a separation
between the lateral surfaces of the light guide at the second end
matches an input separation between the concave first side surface
and the second side surface at the input interface of the light
shaping optical article.
19. The illumination system of claim 30, wherein an extent of both
the light guide and of the input interface of the light shaping
optical article along the transverse direction is in a range of 10
cm and 1 m.
20. The illumination system of claim 30, wherein an extent of the
light guide between the first and second ends is in a range of
10-50 mm.
21. (canceled)
22. The illumination system of claim 30 further comprising a rail
elongated along the transverse direction and attached to the light
guide to support the luminaire module, wherein the first hinging
portion is connected to the rail, and the second hinging portion
comprises a plate.
23. The illumination system of claim 30, wherein the hinging
element extends along the transverse direction.
24. The illumination system of claim 30, wherein the pivot is
configured to allow continuous or discrete variations of the
additional tilt angle.
25-26. (canceled)
27. The illumination system of claim 30 comprising a single
illumination device.
28. The illumination system of claim 30 comprising multiple
illumination devices distributed on a path along their transverse
directions and separated from each other by a predetermined
separation.
29. The illumination system of claim 28, wherein the predetermined
separation is less than a transverse dimension of each illumination
device.
30. An illumination system comprising: one or more illumination
devices, each illumination device comprising: (i) a luminaire
module comprising: a plurality of LEEs distributed along a
transverse direction; a light guide comprising opposing first and
second ends and a pair of opposing lateral surfaces elongated along
the transverse direction and extending in a forward direction
orthogonal to the transverse direction, from the first end to the
second end, the light guide configured to receive at the first end
light from the LEEs and guide the received light in the forward
direction to the second end; and a light shaping optical article
coupled with the second end of the light guide to receive the
guided light as input light in an input angular range, wherein a
prevalent propagation direction of input light in the input angular
range corresponds to the forward direction of the light guide,
wherein the light shaping optical article comprises: a solid optic
having a cross-sectional profile and an elongate extension
perpendicular to a plane of the cross-sectional profile, the
cross-sectional profile of the solid optic comprising: an input
interface in contact with the second end of the light guide; a
convex output surface opposite the input interface; a concave first
side surface extending between the input interface and the convex
output surface; and a second side surface opposite the concave
first side surface extending from between the input interface to
the convex output surface, wherein the concave first side surface
and the convex output surface are shaped and arranged such that,
when the solid optic receives at the input interface the input
light with the input angular range in a plane of the
cross-sectional profile, the solid optic guides the light to and
emits the light from the output surface in an output angular range
in the plane, where a prevalent propagation direction of output
light in the output angular range is tilted by a tilt angle .alpha.
toward the second side surface relative to the prevalent
propagation direction of input light in the input angular range;
(ii) a hinging element comprising a first hinging portion coupled
with the luminaire module, a second hinging portion pivotally
connected to the first hinging portion and configured to form a
pivot parallel to the transverse direction, and the pivot
configured to allow tilting the light guide relative to the second
hinging portion by an additional tilt angle .theta. in an angular
direction; and (iii) an adjustable orientation reflector that
comprises a reflector support coupled with the luminaire module, a
reflector element pivotally connected to the reflector support and
configured to form a reflector pivot parallel to the transverse
direction, wherein the reflector pivot is adjacent an intersection
between the concave first surface and the convex output surface of
the light shaping optical article, and the reflector pivot
configured to allow swinging the reflector element into paths of at
least some of the output light and to allow tilting the reflector
element relative to the light guide by a reflector tilt angle
.phi./2 in the same angular direction as the tilt angle .alpha.
between the prevalent propagation direction of output light in the
output angular range and the prevalent propagation direction of
input light in the input angular range, such that the prevalent
propagation direction of the output light that reflects off the
reflector is tilted relative to the second hinging portion by a sum
of the tilt angle, the additional tilt angle and twice the
reflector tilt angle, .alpha.+.theta.+.phi.; and a mount to which
the second hinging portion of each illumination device is connected
to support the luminaire module of the illumination device inside a
recession of a ceiling adjacent a wall, wherein the mount is
parallel to the wall.
31. The illumination system of claim 30, wherein the reflector
element has a dimension orthogonal to the transverse direction in a
range of 5-10 cm.
32. The illumination system of claim 30, wherein the reflector
element is a flat plate.
33. The illumination system of claim 30, wherein the reflector
element is coated with reflective material.
34. The illumination system of claim 30, wherein the reflector
pivot comprises actuators to adjust the reflector tilt.
35. The illumination system of claim 30, wherein the mount
comprises actuators to adjustably position the convex output
surface of the light shaping optical article relative to a level of
the ceiling, and a portion of the reflector element protrudes from
the recession below the ceiling level.
36-37. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit under 35 U.S.C.
.sctn.119(e)(1) of U.S. Provisional Application No. 62/081,482,
filed on Nov. 18, 2014, which is incorporated by reference
herein.
TECHNICAL FIELD
[0002] The present disclosure relates generally to luminaires for
illuminating proximate target surfaces typically in a slightly
grazing to grazing configuration, for example to wall wash or
grazer luminaires including solid state-based light guide
illumination devices.
BACKGROUND
[0003] Light sources are used in a variety of applications, such as
providing general illumination and providing light for electronic
displays (e.g., LCDs). Historically, incandescent light sources
have been widely used for general illumination purposes.
Incandescent light sources produce light by heating a filament wire
to a high temperature until it glows. The hot filament is protected
from oxidation in the air with a glass enclosure that is filled
with inert gas or evacuated. Incandescent light sources are
gradually being replaced in many applications by other types of
electric lights, such as fluorescent lamps, compact fluorescent
lamps (CFL), cold cathode fluorescent lamps (CCFL), high-intensity
discharge lamps, and solid state light sources, such as
light-emitting diodes (LEDs).
SUMMARY
[0004] The present disclosure relates to wall wash luminaires that
include a solid state-based light guide illumination device.
[0005] In general, innovative aspects of the technologies described
herein can be implemented in an illumination device that includes
one or more of the following aspects:
[0006] In a first aspect, a light shaping optical article includes
a solid optic having a cross-sectional profile including an input
interface; a convex output surface opposite the input interface; a
concave first side surface extending between the input interface
and the convex output surface; and a second side surface opposite
the concave first side surface extending from between input
interface to the convex output surface. Here, the concave first
side surface and the convex output surface are shaped and arranged
such that, when the solid optic receives input light at the input
interface having an input angular range in a plane of the
cross-sectional profile the solid optic guides the light to and
emits the light from the output surface in an output angular range
in the plane, where a prevalent propagation direction of output
light in the output angular range is tilted toward the second side
surface relative to a prevalent propagation direction of input
light in the input angular range. Additionally, the solid optic has
an elongate extension extending from the plane of the
cross-sectional profile.
[0007] The foregoing and other embodiments can each optionally
include one or more of the following features, alone or in
combination. In some implementations, the elongate extension of the
solid optic can be perpendicular to the plane of the
cross-sectional profile.
[0008] In some implementations, the second side surface can be
planar. In some implementations, the solid optic is configured so
that a divergence of output light in the output angular range can
be smaller than a divergence of input light in the input angular
range. In some implementations, the solid optic is configured so
that a relative tilt angle .alpha. between the prevalent
propagation direction of output light in the output angular range
and the prevalent propagation direction of input light in the input
angular range can be in a tilt range of 3.degree. to 30.degree..
For example, the tilt range is 10.degree. to 20.degree..
[0009] In some implementations, the concave first side surface and
the second side surface are shaped and arranged relative to each
other such that, for a given divergence of the input angular range,
the input light received by the solid optic can reach the convex
output surface either directly or via a single reflection off the
concave first side surface or the second side surface. In some
implementations, the convex output surface can include a diffusion
pattern. In some implementations, the disclosed light shaping
optical, further can included a diffusive film attached to the
convex output surface.
[0010] In some implementations, the solid optic can include plastic
material. In some implementations, a separation between the concave
first side surface and the second side surface at the input
interface can be less than 20 mm. For example, the separation is
less than 10 mm. In some implementations, a separation between the
input interface and the convex output surface can be less than 50
mm. For example, the separation between the input interface and the
convex output surface is less than 25 mm.
[0011] In a second aspect, a luminaire module includes a plurality
of LEEs distributed along a transverse direction; a light guide
including opposing first and second ends and a pair of opposing
lateral surfaces elongated along the transverse direction and
extending in a forward direction orthogonal to the transverse
direction, from the first end to the second end, the light guide
configured to receive at the first end light from the LEEs and
guide the received light in the forward direction to the second
end; and the light shaping optical article of the first aspect
coupled with the second end of the light guide at the input
interface to receive the guided light as the input light in the
input angular range. Here, the forward direction of the light guide
corresponds to the prevalent propagation direction of input light
in the input angular range.
[0012] The foregoing and other embodiments can each optionally
include one or more of the following features, alone or in
combination. In some implementations, the disclosed luminaire
module can included one or more optical couplers configured to
collimate light emitted by the LEEs and to provide the collimated
light to the first end of the light guide. In some implementations,
the LEEs can be LEDs that provide white light. In some
implementations, the lateral surfaces of the light guide can be
planar and parallel. In some implementations, a separation between
the lateral surfaces of the light guide at the second end can match
an input separation between the concave first side surface and the
second side surface at the input interface of the light shaping
optical article. In some implementations, an extent of both the
light guide and of the input interface of the light shaping optical
article along the transverse direction can be in a range of 10 cm
and 1 m. For example, the extent of the light guide between the
first and second ends is in a range of 10-50 mm.
[0013] In a third aspect, an illumination device includes the
luminaire module of the second aspect and a hinging element. Here,
the hinging element includes (i) a first hinging portion coupled
with the luminaire module, (ii) a second hinging portion pivotally
connected to the first hinging portion and configured to form a
pivot parallel to the transverse direction, and (iii) the pivot
configured to allow tilting the light guide relative to the second
hinging portion by an additional tilt angle .theta. in an angular
direction, such that the prevalent propagation direction of output
light in the output angular range is tiltable relative to the
second hinging portion by a sum of the tilt angle and the
additional tilt angle, .alpha.+.theta..
[0014] The foregoing and other embodiments can each optionally
include one or more of the following features, alone or in
combination. In some implementations, the disclosed illumination
device can include a rail elongated along the transverse direction
and attached to the light guide to support the luminaire module.
Here, the first hinging portion is connected to the rail, and the
second hinging portion includes a plate. In some implementations,
the hinging element can be elongated along the transverse
direction. In some implementations, the pivot is configured to
allow continuous or discrete variations of the additional tilt
angle.
[0015] In a fourth aspect, an illumination device includes the
luminaire module of the second aspect and an adjustable orientation
reflector. Here, the adjustable orientation reflector includes (i)
a reflector support coupled with the luminaire module, (ii) a
reflector element pivotally connected to the reflector support and
configured to form a reflector pivot parallel to the transverse
direction, wherein the reflector pivot is adjacent an intersection
between the concave first surface and the convex output surface of
the light shaping optical article. The reflector pivot is
configured to allow swinging the reflector element into paths of at
least some of the output light and to allow tilting the reflector
element relative to the light guide by a reflector tilt angle
.phi./2 in the same angular direction as the tilt angle .alpha.
between the prevalent propagation direction of output light in the
output angular range and the prevalent propagation direction of
input light in the input angular range, such that the prevalent
propagation direction of the output light that reflects off the
reflector is tilted relative to the prevalent propagation direction
of input light in the input angular range by a sum of the tilt
angle and the reflector tilt angle, .alpha.+.phi..
[0016] In a fifth aspect, an illumination system includes at least
one illumination device of the third aspect and a mount to which
the second hinging portion of the illumination device is connected
to support the luminaire module of the illumination device inside a
recession of a ceiling adjacent a wall. Here, the mount is parallel
to the wall.
[0017] The foregoing and other embodiments can each optionally
include one or more of the following features, alone or in
combination. In some implementations, the disclosed illumination
system can include a single illumination device. In other
implementations, the disclosed illumination system can include
multiple illumination devices distributed on a path along their
transverse directions and separated from each other by a
predetermined separation. For example, the predetermined separation
is less than a transverse dimension of each illumination
device.
[0018] In some implementations, the disclosed illumination system
can include an adjustable orientation reflector. Here, the
adjustable orientation reflector includes a reflector support
coupled with the luminaire module, and a reflector element
pivotally connected to the reflector support and configured to form
a reflector pivot parallel to the transverse direction. The
reflector pivot is adjacent an intersection between the concave
first surface and the convex output surface of the light shaping
optical article, and the reflector pivot is configured to allow
swinging the reflector element into paths of at least some of the
output light and to allow tilting the reflector element relative to
the light guide by a reflector tilt angle .phi./2 in the same
angular direction as the tilt angle .alpha. between the prevalent
propagation direction of output light in the output angular range
and the prevalent propagation direction of input light in the input
angular range, such that the prevalent propagation direction of the
output light that reflects off the reflector is tilted relative to
the second hinging portion by a sum of the tilt angle, the
additional tilt angle and the reflector tilt angle,
.alpha.+.theta.+.phi..
[0019] In some implementations of the illumination device of the
fourth aspect or in some implementations of the disclosed
illumination system, the reflector element can have a dimension
orthogonal to the transverse direction in a range of 5-10 cm. In
some implementations of the illumination device of the fourth
aspect or of the disclosed illumination system, the reflector
element can be a flat plate. In some implementations of the
illumination device of the fourth aspect or in some implementations
of the disclosed illumination system, the reflector element can be
coated with reflective material. In some implementations of the
illumination device of the fourth aspect or in some implementations
of the disclosed illumination system, the reflector pivot can
include actuators to adjust the reflector tilt.
[0020] In some implementations of the disclosed illumination
system, the mount can include actuators to adjustably position the
convex output surface of the light shaping optical article relative
to a level of the ceiling. In this case, a portion of the reflector
element can protrude from the recession below the ceiling
level.
[0021] The details of one or more implementations of the
technologies described herein are set forth in the accompanying
drawings and the description below. Other features, aspects, and
advantages of the disclosed technologies will become apparent from
the description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1A-1D show aspects of an example of a light shaping
optical article to be used as part of a wall wash luminaire.
[0023] FIGS. 2A-2F show structural aspects of an example of a light
shaping optical article.
[0024] FIGS. 3A-3C show aspects of an example of an illumination
device based on a light guide luminaire module that includes a
light shaping optical article.
[0025] FIGS. 4A-4D show aspects of an example of a wall wash
luminaire that includes the illumination device from FIGS.
3A-3B.
[0026] FIGS. 5A-5C show aspects of another example of an
illumination device based on a light guide luminaire module that
includes a light shaping optical article.
[0027] FIGS. 6A-6B show aspects of another example of a wall wash
luminaire that includes a combination of the illumination devices
of FIGS. 3A and 5A.
[0028] FIGS. 7A-7C show results of simulation of the wall wash
luminaire from FIG. 4A in an arrangement of FIG. 4B.
[0029] FIGS. 8A-8C, 9A-9C, 10A-10C and 11A-11D show results of
simulation of the wall wash luminaire of FIG. 6 in the arrangement
of FIG. 4B.
[0030] FIGS. 12A-12C, 13A-13C and 14A-14C show results of
simulation of the wall wash luminaire of FIG. 6 in arrangements of
FIGS. 4B, 4C and 4D, respectively.
[0031] Reference numbers and designations in the various drawings
indicate exemplary aspects, implementations of particular features
of the present disclosure.
DETAILED DESCRIPTION
[0032] The present disclosure relates to luminaires for providing
wall wash illumination. The disclosed luminaires can efficiently
guide and distribute light emitted by solid-state light sources
towards target surfaces, e.g., towards walls, panels or other
target surfaces, to uniformly illuminate the target surfaces.
Target surfaces can have vertical, horizontal or other
arrangements. With respect to illumination the term uniformity is
intended to refer to constraining the maximum-to-minimum ratio
(MMR) of the illuminance caused by the luminaire on the target
surface. For example, the MMR may be constrained to be lower than
4:1, 3:1 or 2:1.
[0033] A light shaping optical article is disclosed that is
configured to provide light in an output angular range that is
tilted relative to a prevalent direction of propagation of light in
an input angular range and distributed to illuminate a defined
target surface within a predetermined MMR. As used herein,
providing light in an "angular range" refers to providing light
that propagates in one or more prevalent directions in which each
has a divergence with respect to the corresponding prevalent
direction. In this context, the term "prevalent direction of
propagation" refers to a direction along which a portion of an
intensity distribution of the propagating light has a maximum. For
example, the prevalent direction of propagation associated with the
angular range can be an orientation of a lobe of the (angular)
intensity distribution. (See, e.g., FIG. 1C or 3C.) Also in this
context, the term "divergence" refers to a solid angle outside of
which the intensity distribution of the propagating light drops
below a predefined fraction of a maximum of the intensity
distribution. For example, the divergence associated with the
angular range can be the width of the lobe of the intensity
distribution. The predefined fraction can be 10%, 5%, 1%, or other
values, depending on the lighting application.
[0034] The disclosed light shaping optical article can be used in a
light guide luminaire module (also referred to simply as a
luminaire module), such that light in the input angular range is
emitted by solid-state light sources and guided by a light guide of
the light guide luminaire module to an input aperture of the light
shaping optical article. In some cases, a propagation direction of
the light output by the light shaping optical article can be
further tilted by incorporating the light guide luminaire module in
an illumination device that uses a hinging element configured to
tilt the light guide of the light guide luminaire module relative
to the target surface. Alternatively, the propagation direction
tilt of the output light can be increased by incorporating the
light guide luminaire module in another illumination device that
uses a reflector arranged to deflect the light output by the light
shaping optical article relative to the target surface. An
illumination system that includes either of the foregoing
illumination devices, or a combination thereof, can be recessed in
a ceiling at a desired distance from the target wall to operate as
a wall wash.
(i) Light Shaping Optical Article
[0035] FIG. 1A illustrates a block diagram of a light shaping
optical article 140 configured to tilt, by a tilt angle
.alpha..noteq.0, a prevalent propagation direction of light in an
output angular range 145 relative to a prevalent propagation
direction of light in an input angular range 135. Here, a reference
system (x,y,z) has a z-axis aligned to the prevalent propagation
direction of light in input angular range 135. In the example shown
in FIG. 1A, a target surface 190 also is aligned parallel to the
z-axis. However, the prevalent propagation direction of light in
input angular range 135 can, but does not have to, be parallel to
the target surface 190.
[0036] The light shaping optical article 140 is formed from a
solid, transparent material (with n>1). For example, the solid,
transparent material can be glass with a refractive index of about
1.5. As another example, the solid, transparent material can be
plastic with a refractive index of about 1.5-1.6.
[0037] The light shaping optical article 140 includes an input
surface 142 through which input light with the input angular range
135 enters into the light shaping optical article 140, and an
output surface 144 through which output light with the output
angular range 145 exits from the light shaping optical article 140.
Further, the light shaping optical article 140 has a first side
surface 146 and a second side surface 148. The first side surface
146 is concave and the output surface 144 is convex. The second
side surface 148 of the light shaping optical article 140 can have
negative, zero or positive curvature. Additionally, the concave
first side surface 146 and convex output surface 144 are configured
such that the prevalent propagation direction of light in output
angular range 145 is tilted by the tilt angle .alpha. toward the
second side surface 148 relative to prevalent propagation direction
of light in the input angular range 135. In this manner, .alpha. is
a tilt of the prevalent propagation direction of output angular
range 145 relative to the z-axis.
[0038] FIG. 1B shows that the light shaping optical article 140 is
elongated along the x-axis. In this manner, input angular range 135
and output angular range 145 can be the same in the (z-x) plane
while ignoring refraction at the output surface. An input interface
corresponding to the input surface 142 represents an extended light
source. In implementations in which the input surface 142 of the
light shaping optical article 140 is coupled to an output end of a
light guide (as it is in the case illustrated in FIG. 3A), a
prevalent propagation direction of the input angular range 135 can
be parallel to the light guide.
[0039] A divergence of the input angular range 135 in a (y-z) plane
(a plane perpendicular to the x-axis) can be that of a Lambertian
or narrower distribution, for example. As another example, a
distribution of light within the input angular range 135 in the
(y-z) plane can also have more than one peak. For solid light
guides, the divergence of the input angular range is typically
narrow enough to allow all light to be guided within the light
guide via total internal reflection (TIR). Depending on the
implementation, a lateral distribution of light within the input
angular range 135 in the (x-z) plane (e.g., parallel to the x-axis)
can be shaped similarly to the distribution of light within the
input angular range 135 in the (y-z) plane. In some
implementations, such a lateral distribution can have a bat-wing
profile with multiple lobes, for example. Divergence in the (x-z)
plane of the output angular range 145 is determined by the
divergence of the input angular range 135, and may be affected by
the refractive indices at and the curvatures and arrangements of
surfaces 144, 146 and 148, for example.
[0040] FIG. 1C shows a light intensity distribution 101 of the
light output by the light shaping optical article 140 in the (y-z)
plane. Here, the z-axis is aligned along the prevalent propagation
direction of light in the input angular range 135. A lobe 145' of
the light intensity distribution 101 represents the light output by
the light shaping optical article 140 in the output angular range
145. A bisector of the lobe 145' corresponds to the prevalent
propagation direction of light of the output angular range 145.
Here, the bisector of the lobe 145' is tilted by a tilt angle
.alpha.=.alpha..sub.lobe relative to the z-axis, and a value of
.alpha..sub.lobe is about 40.degree.. In other implementations, the
value of .alpha..sub.lobe can be different, for example about 5,
10, 30 or 50.degree.. A width at half-max of the lobe 145'
corresponds to the divergence of light of the output angular range
145. Here, the width at half-max of the lobe 145' has a value of
about 20.degree.. In other implementations, the value of the width
at half-max of the lobe 145' can be about 5, 10 or 30.degree..
Angles .alpha..sub.min and .alpha..sub.max define an angular
interval outside of which the light intensity drops to less than 5%
from the peak intensity value of the lobe 145'.
[0041] Once the tilt .alpha., divergence (e.g., the width of lobe
145' of the light intensity distribution 101) of output angular
range 145 and the corresponding intensity distribution are
specified through design of the light shaping optical article 140,
a distance "d"--from an "effective center" of the convex output
surface 144 of the light shaping optical article 140 to the target
surface 190 of height H--can be varied to control uniformity of the
illuminance on the target surface. As noted, this can be defined
for example as I.sub.MAX/I.sub.min below a maximum value N:
1<I.sub.MAX/I.sub.min<N, over the entire height H of target
surface 190.
[0042] Depending on the embodiment, parameters d, a and the
divergence of the output angular range 145 may determine a height,
denoted z.sub.spot, on the target surface 190 above ground (z=0)
where the prevalent direction of propagation (denoted in
dashed-line) of the output angular range 145 intersects the target
surface 190, for example. As shown in the analyses illustrated in
FIGS. 7-14, the intersection point at z.sub.spot can correspond to
maximum intensity I.sub.MAX of the output light on the target
surface 190, and intersections of outer rays of the output angular
range 145--tilted respectively at .alpha..sub.min and
.alpha..sub.MAX relative to the z-axis--can correspond to minimum
intensity I.sub.min of the output light on the target surface
190.
[0043] It is noted that, in general, to control divergence and
prevalent propagation direction of the output angular range 145,
the shape of the concave first side surface 146 is such that a
small element of the noted surface accepts incoming rays from
within a narrow angular range only (to allow that surface element
to be exposed to fewer impinging rays and thereby have more control
to redirect the impinging rays). This can require large lengths of
the noted surface (in forward direction, e.g., along z-axis) or,
shallow incidence angles (corresponding to a small divergence of
the input angular range 135.) As such, light impinging on the
concave first side surface 146 reaches the convex output surface
144 directly rather than being redirected first to the second side
surface 148. Also, the second side surface 148 is shaped and
arranged to receive relatively little light from the extended
source corresponding to the input interface formed by input surface
142. For these reasons, the second side surface 148 plays a limited
role in controlling divergence and prevalent propagation direction
of the output angular range 145 and the corresponding intensity
distribution.
[0044] In this manner, the divergence and propagation direction of
light in the output angular range 145 can be determined largely by
a combination of (i) an optical power of the concave first side
surface 146, (ii) an optical power of the convex output surface 144
and (iii) relative arrangements between the convex output surface
144 and each of the z-axis and the concave first side surface 146.
The specific shapes of the respective surfaces can influence the
intensity distribution and thereby affect the degree of uniformity
of the illuminance on the target surface.
[0045] FIG. 1D shows a ray-diagram for an example implementation of
light shaping optical article 140 to illustrate the noted design
considerations. In this example, light propagates from the input
surface 142 with a narrow input angular range 135 and a prevalent
propagation direction along the z-axis. Rays from the input surface
142 are represented in long-dashed lines. The divergence of the
input angular range 135 is indicated using rays emanating from
points of input surface 142.
[0046] In this example, the concave first side surface 146, the
convex output surface 144 and the second side surface 148 are
shaped and arranged in the following manner. The concave first side
surface 146 intersects the convex output surface 144 at point P. In
some implementations, a leftmost ray from among rays emanating from
an intersection point Q of the dotted normal line with the input
surface 142 is tangent to the concave first side surface 146 at the
point P; and the second side surface 148 is planar and
substantially parallel to rightmost rays emanating from the input
surface 142. Here, the point Q defines a first portion 142a of the
input surface 142 that is a fraction f of the input surface 142,
and a remaining, second portion 142b of the input surface 142 that
is a fraction (1-f) of the input surface 142. For instance, f=10%,
20%, etc. In this manner, points of the first portion 142a
contribute rays that are output by the light shaping optical
article 140 in a first output angular range portion 145a. Here, f/2
of rays contributed by the first portion 142a have a positive
y-component (denoted |.fwdarw.>) and f/2 of rays contributed by
the first portion 142a have a negative y-component (denoted
|.rarw.>) before they reach the output surface 144. The ratio of
rays of the corresponding refracted light after transmission can be
different depending on the shape and arrangement of the output
surface 144. Note that the f/2 rays contributed by the first
portion 142a with components |.rarw.> antiparallel to the y-axis
exit through the convex output surface 144 without reflections from
the concave first side surface 146.
[0047] Moreover, points of the second portion 142b contribute rays
that are output by the light shaping optical article 140 in a
second output angular range portion 145b. Here, (1-f)/2 of rays
contributed by the second portion 142b have a positive y-component
|.fwdarw.> and (1-f)/2 of rays contributed by the second portion
142b have a negative y-component |.rarw.> and are pointing to
the concave first side surface 146. Note that most of the (1-f)/2
rays contributed by second portion 142b with negative y-components
|.rarw.> reflect off the concave first side surface 146, such
that the reflected rays have a positive y-component |.fwdarw.>.
Moreover, the reflected rays with positive y-components
|.fwdarw.> directly reach the convex output surface 144 without
reflections from the second side surface 148. In this manner, upon
exiting the convex output surface 144, components orthogonal to the
forward direction (the z axis) of most of the rays contributed by
the second portion 142b are parallel to the y-axis. As such, the
output angular range 145, which is a sum of the first output
angular range portion 145a and the second output angular range
portion 145b, 145=145a+145b, has more rays with a positive y-axis
component |.fwdarw.>, about (1-f)/2, than rays with a negative
y-axis component |.rarw.>, about f/2. In this manner, a
prevalent direction of propagation of light in the output angular
range 145 has a positive y-axis component |.fwdarw.>.
[0048] An example implementation of the light shaping optical
article 140 disclosed above is described next.
Example of a Light Shaping Optical Article
[0049] FIG. 2A is a cross-section in the (y-z) plane of an example
of a light shaping optical article 240. The light shaping optical
article 240 is formed from a solid material (with refractive index
n>1). For example, the material can be glass with a refractive
index of about 1.5. As another example, the material can be plastic
with a refractive index of about 1.5-1.6. The light shaping optical
article 240 includes an input surface 242, an output surface 244, a
first side surface 246 and a second side surface 248.
[0050] The input surface 242 is formed from a first interface 242'
(also referred to as the 1.sup.st interface), which is represented
above the z-axis in this example, and a second interface 242''
(also referred to as the 2.sup.nd interface), which is represented
below the z-axis in this example. FIG. 2B is a cross-section in the
(y-z) plane of the 1.sup.st interface 242'--the z and y axes have
different scaling. Coordinates of a polyline corresponding to the
1.sup.st interface 242' are given in Table 1.
TABLE-US-00001 TABLE 1 1.sup.st interface 242' Point z (mm) y (mm)
1 0 0 2 0 4.57 3 -1.25 4.57 4 -1.25 5
FIG. 2C is a cross-section in the (y-z) plane of the 2.sup.nd
interface 242''--again, the z and y axes have different scaling.
Coordinates of a polyline corresponding to the 2.sup.nd interface
242'' are given in Table 2.
TABLE-US-00002 TABLE 2 2.sup.nd interface 242'' Point z (mm) y (mm)
1 -1.25 -5 2 -1.25 -4.57 3 0 -4.57 4 0 0
[0051] The input surface 242 of the light shaping optical article
240 can be bonded to an output end of a light guide as described
below in connection with FIG. 3B, for instance. In such case, an
anti-reflective coating may be disposed between the output end of
the light guide and light shaping optical article 240. If the
material of the light shaping optical article 240 is different from
the material from which the light guide is formed, for example an
index matching layer may be disposed between the output end of the
light guide and light shaping optical article 240. In other cases,
the light guide and the light shaping optical article 240 can be
integrally formed.
[0052] FIG. 2D is a cross-section in the (y-z) plane of the second
side surface 248. Coordinates of the section of the second side
surface 248 are given in Table 3--the section is a straight
line.
TABLE-US-00003 TABLE 3 2.sup.nd side surface 248 Point z (mm) y
(mm) 1 -1.25 5 2 18 12
[0053] Here, the second side surface 248 of the light shaping
optical article 240 is planar and plays a minor role in determining
a tilt angle .alpha. relative the z-axis of the propagation
direction of light in the output angular range 145 or a divergence
of the output angular range 145. In some implementations, the
second side surface 248 is uncoated. In such cases, light from the
input surface 242 that impinges on the second side surface 248 at
angles beyond a critical angle .theta.=arcsin(1/n) relative to the
respective surface normal reflects off the second side surface 248
via total internal reflection (TIR). In other implementations, the
second side surface 248 is coated with a reflective coating. In
such cases, light from the input surface 242 that reaches the
second side surface 248 reflects off the second side surface 248
via specular reflection or diffuse reflection or a combination
thereof.
[0054] FIG. 2E is a cross-section in the (y-z) plane of the first
side surface 246. Coordinates of nodes for a fitted curve, e.g., a
spline, corresponding to the first side surface 246 are given in
Table 4.
TABLE-US-00004 TABLE 4 1.sup.st side surface 246 Point z (mm) y
(mm) 1 21 -7.3 2 18.54 -6.93 3 16.08 -6.57 4 13.61 -6.24 5 11.15
-5.94 6 8.67 -5.68 7 6.2 -5.47 8 3.72 -5.3 9 1.23 -5.14 10 -1.25
-5
[0055] Here, the first side surface 246 of the light shaping
optical article 240 is concave and, along with the output surface
244, plays a major role in determining the tilt angle .alpha.
relative to the z-axis of the propagation direction of light in the
output angular range 145 and the divergence of the output angular
range 145. In some implementations, the concave first side surface
246 is uncoated. In such cases, light from the input surface 242
that impinges on the concave first side surface 246 at angles
beyond the critical angle .theta.=arcsin(1/n) reflects off the
concave first side surface 246 via total internal reflection (TIR).
In other implementations, the concave first side surface 246 is
coated with a reflective coating. In such cases, light from the
input surface 242 that reaches the concave first side surface 246
reflects off the concave first side surface 246 via specular
reflection or diffuse reflection or a combination thereof.
[0056] FIG. 2F is a cross-section in the (y-z) plane of the output
surface 244. Coordinates of nodes for a fitted curve, e.g., a
spline, corresponding to the output surface 244 are given in Table
5.
TABLE-US-00005 TABLE 5 output surface 244 Point z (mm) y (mm) 1 18
12 2 18.76 11.28 3 19.48 10.53 4 20.1 9.72 5 20.6 8.83 6 20.98 7.87
7 21.28 6.88 8 21.56 5.88 9 21.81 4.89 10 22.03 3.88 11 22.23 2.87
12 22.36 1.84 13 22.4 0.82 14 22.32 -0.21 15 22.18 -1.23 16 22.01
-2.25 17 21.83 -3.27 18 21.64 -4.28 19 21.44 -5.29 20 21.22 -6.29
21 21.00 -7.3
[0057] Here, the output surface 244 of the light shaping optical
article 240 is convex and, along with the concave first side
surface 246, plays a major role in determining the tilt angle
.alpha. relative the z-axis of the propagation direction of light
in the output angular range 145 and the divergence of the output
angular range 145. In some implementations, the convex output
surface 244 is uncoated. In other implementations, an
anti-reflective coating may be provided on the convex output
surface 244 such that light that reaches the convex output surface
244--directly from the input surface 242 or after reflection off
the concave first side surface 246 or the second side surface
248--can transmit with minimal back reflection. In other
implementations, the convex output surface 244 is coated with a
diffusive coating (e.g., BrightView M PR05.TM.). In such cases,
light from the input surface 242 that reaches the concave first
side surface 246 that reaches the convex output surface
244--directly from the input surface 242 or after reflection off
the concave first side surface 246 or the second side surface
248--can diffuse upon transmission through the convex output
surface 244.
[0058] The light shaping optical article 140 or 240 can be used in
a light guide luminaire module, as described below in connection
with FIG. 3A or 5A, such that light in the input angular range 135
is provided by solid-state light sources and guided by a light
guide of the light guide luminaire module to the input surface 142
or 242 of the light shaping optical article 140 or 240,
respectively. In some cases, when a prevalent propagation direction
(e.g., given in terms of the tilt angle .alpha.) of the light
output by the light shaping optical article 140 or 240 is
insufficiently tilted for uniformly illuminating a target surface
190, e.g., a certain portion of a wall, the prevalent propagation
direction tilt of the output light can be further increased by
incorporating the light guide luminaire module in various
illumination devices as described below.
(ii) Illumination Device Based on Light Guide Luminaire Module with
Light Shaping Optical Article
[0059] FIG. 3A is a block diagram of an example of an illumination
device 300 based on a light guide luminaire module 302 that
includes a light shaping optical article 340. The light shaping
optical article 340 can be implemented as a light shaping optical
article 140 or 240 described in connection with FIG. 1A or 2A, for
example.
[0060] The light guide luminaire module 302 further includes a
substrate 305, one or more light emitting elements (LEEs) 310 and a
light guide 330. The light guide 330 guides the light provided by
the LEEs 310 along a length D (e.g., along the z-axis of the
Cartesian reference system shown in FIG. 3A.) Optionally, the light
guide luminaire module 302 further includes one or more optical
couplers 320, such that the light guide 330 is coupled at its input
end to the LEEs via the optical coupler(s) 320 and at its output
end to the light shaping optical article 340.
[0061] The illumination device 300 includes a pivoting system
comprising a hinging element 350, for example. The hinging element
350 is configured to allow tilting the light guide 330 of the light
guide luminaire module 302 by an inclination angle
.theta..noteq..theta. relative to the axis z.
[0062] In general, a LEE, also referred to as a light emitter, is a
device that emits radiation in one or more regions of the
electromagnetic spectrum from among the visible region, the
infrared region and/or the ultraviolet region, when activated.
Activation of a LEE can be achieved by applying a potential
difference across components of the LEE or passing a current
through components of the LEE, for example. A LEE can have
monochromatic, quasi-monochromatic, polychromatic or broadband
spectral emission characteristics. Examples of LEEs include
semiconductor, organic, polymer/polymeric light-emitting diodes,
other monochromatic, quasi-monochromatic or other light-emitting
elements. In some implementations, a LEE is a specific device that
emits the radiation, for example a LED die. In other
implementations, the LEE includes a combination of the specific
device that emits the radiation (e.g., a LED die) together with a
housing or package within which the specific device or devices are
placed. Examples of LEEs include also lasers and more specifically
semiconductor lasers, such as vertical cavity surface emitting
lasers (VCSELs) and edge emitting lasers. Further examples of LEEs
include superluminescent diodes and other superluminescent
devices.
[0063] During operation, the LEEs 310 provide light within a first
angular range 115. Such light can have a Lambertian distribution
relative to the optical axes of the one or more LEEs 310 (e.g., the
z-axis.) The light guide 330 can be made from a solid, transparent
material. For example, the material can be glass with a refractive
index of about 1.5. As another example, the material can be plastic
with a refractive index of about 1.5-1.6. Here, the light guide 330
is arranged to receive the light provided by the LEEs 310 at one
end of the light guide 330 and to guide the received light in a
forward direction, e.g., along the z-axis, from the receiving end
to an opposing end of the light guide 330. Here, the distance D
between the receiving end of the light guide 330 and its opposing
end can be 5, 10, 20, 50 or 100 cm, for instance. A combination of
(i) an angular range in which the light is received by the light
guide 330 at the receiving end and (ii) a numerical aperture of the
light guide 330 is configured such that the received light is
guided from the receiving end to the opposing end through
reflection off of light guide side surfaces of the light guide 330.
Depending on the implementation, at least some, if not all, of this
reflection is via total internal reflection (TIR). In some
implementations, the numerical aperture of the light guide 330 is
such that all light provided by the LEEs 310 in the angular range
115 can be injected directly into the light guide 330 at its
receiving end.
[0064] In some implementations, the illumination device 300
includes a light guide luminaire module 302 that has one or more
optical couplers 320, as shown in FIG. 3B, for instance. In such
cases, the one or more optical couplers 320 receive the light from
the LEEs 310 within the first angular range 115 and collimate the
received light within a second angular range 125 in the forward
direction. The one or more optical couplers 320 are shaped to
transform the first angular range 115 into the second angular range
125 via total internal reflection, specular reflection or both.
Moreover, the one or more optical couplers 320 can include a solid
transparent material for propagating light from an input end to an
output end of each of the one or more optical couplers 320. Here,
the divergence of the second angular range 125 is smaller than the
divergence of the first angular range 115. As such, the divergence
of the second angular range 125 is selected such that all light
provided by the coupler(s) 320 in the angular range 125 can be
injected into the light guide 330 at its receiving end.
[0065] Referring now to FIGS. 3A-3B, one or more of the light guide
side surfaces can be planar, curved or otherwise shaped. The light
guide side surfaces can be parallel or non-parallel. In embodiments
with non-parallel light guide side surfaces, a third angular range
135 of the guided light at the opposing end of the light guide 330
is different than the angular range 115 (when the light guide 330
receives the light directly from the LEEs 310) or 125 (when the
light guide 330 receives the light from the couplers 320) of the
light received at the receiving end. Here, the light guide side
surfaces can be optically smooth to allow for the guided light to
propagate forward (e.g., in the positive direction of the z-axis)
inside the light guide 330 through TIR. In this case, the light
guide side surfaces are shaped and arranged with respect to the
z-axis and each other such that the guided light impinges on the
light guide side surfaces at incident angles larger than a critical
angle over the entire distance D from the input end the output end
of the light guide 330. In embodiments with parallel light guide
side surfaces, whether the light guide 330 is solid or hollow, the
third angular range 135 of the guided light at the opposing end of
the light guide 330 has at least substantially the same divergence
as the angular range 115 (when the light guide 330 receives the
light directly from the LEEs 310) or 125 (when the light guide 330
receives the light directly from the couplers 320) of the light
received at the receiving end.
[0066] Additionally, the length D of the light guide 330 (along the
z-axis), a width L of the light guide 330 (along the x-axis) and a
thickness T of the light guide 330 (along the y-axis) are designed
to homogenize the light emitted by the discrete LEEs 310--which are
distributed along the x-axis--as it is guided from the receiving
end to the opposing end of the light guide 330. In this manner, the
homogenizing of the emitted light--as it is guided through the
light guide 330--causes a change of a discrete profile along the
x-axis of the first angular range 115 (when the light guide 330
receives the light directly from the LEEs 310) or the second
angular range 125 (when the light guide 330 receives the light from
the couplers 320) to a continuous profile along the x-axis of the
third angular range 135 in which the discrete profile is partially
or fully blurred.
[0067] Here, light in the third angular range 135 represents the
input light for the light shaping optical article 340 and has a
prevalent propagation direction along the z-axis. Similarly to the
light shaping optical article 140 or 240, the light shaping optical
article 340 is made from a solid, transparent material. For
example, the material can be glass with a refractive index of about
1.5. As another example, the material can be plastic with a
refractive index of about 1.5-1.6. The light shaping optical
article 340 has an input surface 342 that is coupled to the output
end of the light guide 330 to receive the guided light. The input
surface 342 of the light shaping optical article 340 adjacent to
the output edge of the light guide 330 is optically coupled to the
output edge. For example, the light shaping optical article 340 can
be affixed to light guide 330 using an index matching fluid,
grease, or adhesive. In some implementations, light shaping optical
article 340 is fused to light guide 330 or they are integrally
formed from a single piece of material.
[0068] Moreover, the light shaping optical article 340 includes a
convex output surface 344, a concave first side surface 346 and a
second side surface 348. As described above in connection with
FIGS. 1A-1D and 2A-2F, a combination of (i) an optical power of the
concave first side surface 346, (ii) an optical power of the convex
output surface 344 and (iii) relative arrangements between the
convex output surface 344 and each of the light guide direction
(here the z-axis) and the concave first side surface 346 of the
light shaping optical article 340 determines the divergence of
light in the output angular range 145 and a tilt angle .alpha. of
prevalent propagation direction of the light in the output angular
range 145 relative to prevalent propagation direction of light in
the third angular range 135.
[0069] In this manner, the one or more optical couplers 320, light
guide 330 and the light shaping optical article 340 of the light
guide luminaire module 302 are arranged and configured to translate
and redirect light emitted by LEEs 310 away from the LEEs before
the light is output into the ambient environment. The spatial
separation of the place of generation of the light, also referred
to as the physical (light) source, from the convex output surface
344--where light is extracted from the light guide luminaire module
302--also referred to as a virtual light source or a virtual
filament, can facilitate design of the light guide luminaire module
302. In this manner, a virtual filament can be configured to
provide substantially non-isotropic light emission with respect to
planes parallel to an optical axis of the light guide luminaire
module 302 (for example the z-axis.) In contrast, a typical
incandescent filament generally emits substantially isotropically
distributed amounts of light. The virtual filament(s) may be viewed
as one or more portions of space from which substantial amounts of
light appear to emanate. Furthermore, separating the LEEs 310, with
their predetermined optical, thermal, electrical and mechanical
constraints, from the place of light extraction, may facilitate a
greater degree of design freedom of the light guide luminaire
module 302 and allows for an extended optical path, which can
permit a predetermined level of light mixing before light is output
from the light guide luminaire module 302.
[0070] In the example illustrated in FIG. 3A, the hinging element
350 of the illumination device 300 includes a first hinging portion
352 coupled with one of the side surfaces of the light guide 330 of
the light guide luminaire module 302 that is on the same side of
the light guide as the concave first side surface 346 of the light
shaping optical article 340. The hinging element 350 further
includes a second hinging portion 354 connected to the first
hinging portion 352. The first hinging portion 352 and the second
hinging portion 354 are connected together at a pivot 355
orthogonal to the prevalent propagation direction of light in the
third angular range 135 (here, the z-axis) and the prevalent
propagation direction of light in the output angular range 145. In
some implementations, the pivot 355 can include angular
displacement actuators for adjusting the tilt angle .theta. in
increments of .lamda..theta.=0.1, 0.5, or 1.degree.. In some
implementations, the hinging element 350 can be configured as a
friction hinge and provide a continuous resilient pivot.
[0071] In this manner, the pivot 355 is configured to adjustably
tilt the light guide 330 relative to the second hinging portion 354
by an additional tilt angle .theta., here in an angular direction
opposing the tilt angle .alpha.. As such, the prevalent propagation
direction of output light in the output angular range 145 is tilted
relative to the second hinging portion 354 by a sum of the tilt
angle and the additional tilt angle, .alpha.+.theta.. In a
Cartesian coordinate system (x,y',z') rotated about the x-axis of
the Cartesian coordinate system (x,y,z), a tilt angle between the
prevalent propagation direction of output light in the output
angular range 145 and the second hinging portion 354 is equal to
the sum of the tilt angle and the additional tilt angle,
.alpha.+.theta..
[0072] In the example illustrated in FIG. 3B, the illumination
device 300 further includes a rail 360 arranged and configured to
support the light guide luminaire module 302. Here, the rail 360
has a U profile in the (y,z) plane and is elongated along the
x-axis. A surface of the rail 360 that is parallel to the (x,y)
plane is disposed adjacent to the substrate 305 of the light guide
luminaire module 302, and the surfaces of the rail 360 that are
parallel to the (x,z) plane are coupled to the side surfaces of the
light guide 330 along a top fraction of the length D of the light
guide 330. The top fraction can be 10, 30 or 50% of D, for
instance.
[0073] Further in the example illustrated in FIG. 3B, the first
hinging portion 352 of the hinging element 350 includes a plate.
Here, the first hinging portion 352 is attached to one of the
surfaces of the rail 360 that are parallel to the (x,z) plane on
the same side of the light guide 330 as the concave side surface
346 of the light shaping optical article 340. Furthermore, the
second hinging portion 354 of the hinging element 350 includes a
plate. The respective plates of the first and second hinging
portions 352, 354 of the hinging element 350 are rotatably coupled
to each other at the pivot 355. Furthermore in the example
illustrated in FIG. 3B, the illumination device 300 is coupled to a
mount 370 parallel to the (x,z') plane by attaching the second
hinging portion 354 to the mount 370. In this manner, the hinging
element 350 tilts the prevalent propagation direction of the guided
light in the third angular range 135 by a tilt angle .theta.
relative to the mount 370, and the light shaping optical article
340 tilts the already tilted prevalent propagation direction of the
guided light in the third angular range 135 by a tilt angle .alpha.
relative to the light guide 330. As a cumulative effect, the
illumination device 300 outputs light in the output angular range
145 having a prevalent propagation direction that is tilted by a
cumulative angle .theta.+.alpha. relative to the mount 370.
[0074] FIG. 3C shows a light intensity distribution 101' of the
light output by the illumination device 300 in the (y'-z') plane.
Note that the z'-axis (parallel to the second hinging portion 354)
is rotated about the x-axis relative to the z-axis (parallel to
light guide 330). In some implementations, the z'-axis can be
aligned along a target surface 190, e.g., along a wall. A lobe 145'
of the light intensity distribution 101' represents the light
output by the illumination device 300 in the output angular range
145. A bisector of the lobe 145' corresponds to the prevalent
propagation direction of light the output angular range 145. Here,
the bisector of the lobe 145' is tilted by a tilt angle
.alpha.+.theta..apprxeq.45.degree. relative to the z'-axis. For
example, .theta..apprxeq.5.degree. represents the tilt of the
prevalent propagation direction of the guided light in the third
angular range 135 relative to the z'-axis as caused by the pivot
355, and .alpha..apprxeq.40.degree. represents the tilt of the
prevalent propagation direction of the output light in the output
angular range 145 relative to the z-axis as caused by the light
shaping optical article 340. Useful tilt angles .alpha.+.theta. may
depend on the lighting application. A width at half-max of the lobe
145' corresponds to the divergence of light the output angular
range 145. Here, the width at half-max of the lobe 145' has a value
of about 20.degree..
[0075] An illumination system that includes the illumination device
300 can be recessed in a ceiling at a desired distance from the
target wall to operate as a wall wash, wall grazer or other
lighting fixture, for example.
(iii) Wall Wash Luminaire Based on Illumination Device(s) with
Light Guide Luminaire Module and Hinging Element
[0076] FIG. 4A is a block diagram of an example of an illumination
system 400 based on one or more illumination devices, each of which
includes a light guide luminaire module 302 and a hinging element
350. In this example, the illumination device is implemented as the
illumination device 300 described above in connection with FIGS.
3A-3B. The illumination system 400 further includes a housing 494.
The housing 494 can be configured to support one or more
illumination devices at predetermined distances (e.g., along the
y'-axis) from a target surface 490 from a wall, panel, and/or from
each other. In the example illustrated in FIG. 4A, the housing 494
of the illumination system 400 is recessed inside a ceiling 492.
Further in this example, the ceiling 492 and the wall 490 are
respectively orthogonal and parallel to the z'-axis. The
illumination system 400 also includes a mount 470 to attach the
illumination device(s) to the housing 494. In this example, the
mount 470 is aligned parallel to the wall 490, along the
z'-axis.
[0077] Each of the illumination devices of the illumination system
400 includes a rail 360 that supports the light guide luminaire
module 302. The light guide luminaire module 302 includes a light
guide 330 and a light shaping optical article 340. Here, the light
shaping optical article 340 is implemented as the light shaping
optical article 240 described above in connection with FIGS. 2A-2F.
A first hinging portion of the hinging element 350 is attached to a
surface of the rail 360 that is parallel to the light guide 330 and
on the same side of the light guide 330 as the first concave
surface of the light shaping optical article 340. A second hinging
portion of the hinging element 350 is attached to the mount 470.
The pivot 355 of the hinging element 350 orients the light guide
330 (which is parallel to the z-axis) at a tilt angle .theta.
relative the z'-axis. The light shaping optical article 340 further
tilts the light guided by the light guide 330 by an additional tilt
angle .alpha. (relative the z-axis) for a total tilt angle
.theta.+.alpha. relative the z'-axis. In this manner, a prevalent
propagation direction (represented by dashed-line) of light output
by the illumination system 400 is tilted by an angle
.theta.+.alpha. relative to the z'-axis.
[0078] The light guide luminaire module 302 and the hinging element
350, as well as the housing 494, are elongated along the x-axis. A
position of the housing 494 can vary relative the wall 490. In this
manner, a distance along y'-axis between output surface of the
light shaping optical article 340 and the wall 490 is d'.
[0079] Moreover, in this example, a position of the mount 470 along
a side surface of the housing 494 can be adjusted using an
adjustment element I/O, such that output surface of the light
shaping optical article 340 is recessed inside the housing 494 by a
desired distance relative to a level of the ceiling 492. The
adjustment element I/O can include linear displacement actuators
for adjusting a distance z' from the level of the ceiling 492 in
increments of .DELTA.z=0.1, 0.5, or 1 cm.
[0080] FIG. 4B shows a view in the (x,y')-plane of an arrangement
(i) of the illumination system 400. In the arrangement (i), the
illumination system 400 includes a single illumination device
attached to a side surface of the housing 494 through the mount
470. In this example, a width L (along the x-axis) of the light
guide luminaire module 302 of the illumination device is about 60
cm. Note that respective length scales along the x-axis and along
the y'-axis are different in FIG. 4B. Dimensions of components such
as the housing(s) and the illumination device may not be to scale
and/or exaggerated relative to one another even within the same
direction.
[0081] FIG. 4C shows a view in the (x-y')-plane of an arrangement
(ii) of the illumination system 400. In the arrangement (ii), the
illumination system 400 includes three illumination devices
attached to a side surface of a single housing 494 through the
mount 470. Alternatively, each illumination device can have its own
housing (not illustrated). Here, a width L (along the x-axis) of
the light guide luminaire module 302 of each of the illumination
devices is about 60 cm, and a separation .DELTA. between light
guide luminaire modules 302 of adjacent illumination devices is
about 60 cm. Note that respective length scales along the x-axis
and along the y'-axis are different in FIG. 4C.
[0082] FIG. 4D shows a view in the (x-y')-plane of an arrangement
(iii) of the illumination system 400. In the arrangement (iii), the
illumination system 400 includes five illumination devices attached
to a side surface of a single housing 494 through the mount 470.
Here, a width L (along the x-axis) of the light guide luminaire
module 302 of each of the illumination devices is about 60 cm, and
there is no separation .DELTA. between light guide luminaire
modules 302 of adjacent illumination devices: .DELTA.=0. Note that
respective length scales along the x-axis and along the y'-axis are
different in FIG. 4D.
[0083] Illumination devices 300 and illumination systems 400 have
been described above that use a light guide luminaire module 302 in
conjunction with a hinging element 350 to further increase a
prevalent propagation direction tilt of the light output by the
light guide luminaire module 302 when the prevalent propagation
direction is insufficiently tilted for uniformly illuminating a
target surface 190, e.g., a certain portion of a wall. Other ways
to further increase the prevalent propagation direction tilt of
light output by a light guide luminaire module 302 are described
below.
(iv) Another Illumination Device Based on Light Guide Luminaire
Module with Light Shaping Optical Article
[0084] FIGS. 5A and 5B show aspects of an example of another
illumination device 500 based on a light guide luminaire module 302
that includes a light shaping optical article 340. The light
shaping optical article 340 can be implemented as a light shaping
optical article 140 or 240 described in connection with FIG. 1A or
2A, for example.
[0085] The light guide luminaire module 302 further includes a
substrate 305, one or more light emitting elements (LEEs) 310 and a
light guide 330. The light guide 330 guides the light provided by
the LEEs 310 along a length D. Optionally, the light guide
luminaire module 302 further includes one or more optical couplers
320, such that the light guide 330 is coupled at its input end to
the optical coupler(s) 320 and at its output end to the light
shaping optical article 340. These components of the light guide
luminaire module 302 as well as their respective and combined
functionalities have been described in detail in connection with
FIGS. 3A-3B. As noted above, a combination of (i) an optical power
of a concave first side surface 346 of the light shaping optical
article 340, (ii) an optical power of a convex output surface 344
of the light shaping optical article 340 and (iii) relative
arrangements between the convex output surface 344 and each of a
light guide direction (here the z-axis) and the concave first side
surface 346 determines a divergence of light in an output angular
range 145 and a tilt angle .alpha. of prevalent propagation
direction of the light in the output angular range 145 relative to
prevalent propagation direction of the guided light in a third
angular range 135.
[0086] The illumination device 500 includes, in addition to the
light guide luminaire module 302, an adjustable orientation
reflector 580 arranged and configured to reorient a prevalent
propagation direction of the light output in the output angular
range 145 by an additional angle .phi..noteq.0. In this manner,
light is output by the illumination device 500 in a modified output
angular range 145' along a prevalent propagation direction having a
cumulative tilt angle .alpha.+.phi. relative to the axis z.
[0087] In the examples illustrated in FIGS. 5A and 5B, the
adjustable orientation reflector 580 includes a reflector support
582 and a reflector element 584. In this example, the reflector
support 582 is disposed adjacent one of the side surfaces of the
light guide 330. The reflector support 582 is located on the same
side of the light guide as the concave first side surface 346 of
the light shaping optical article 340. The reflector support 582
and the reflector element 584 are connected together at a pivot 585
orthogonal to the prevalent propagation direction of the guided
light in the third angular range 135 (here, the z-axis) and the
prevalent propagation direction of the output light in the output
angular range 145. The reflector support 582, the reflector element
584 and the pivot 585 extend over the width L of the light guide
luminaire module 302 along the x-axis.
[0088] The pivot 585 can be arranged relative to the light shaping
optical article 340 adjacent to an intersection of the concave
first side surface 346 and the convex output surface 344. In some
implementations, the pivot 585 can include angular displacement
actuators for adjusting the tilt angle .phi. in discrete increments
of .DELTA..phi.=0.1, 0.5, or 1.degree., for example, or via a
continuous pivot. The pivot 585 is configured to adjustably tilt
the reflector element 584 relative to the light guide direction
(here the z-axis) by a reflector angle .phi./2. The reflector angle
.phi./2 can be 5, 8, or 10.degree., for instance. In this manner,
at least a portion of the light output by the light shaping optical
article 340 in the output angular range 145 reflects off the
reflector element 584, such that the reflected light prevalently
propagates in a direction that is tilted by a tilt angle .phi.
relative to the prevalent propagation direction of the output light
in the output angular range 145. The reflected light is provided by
the illumination device 500 in the modified output angular range
145' and has a prevalent propagation direction that has a
cumulative tilt angle .alpha.+.phi. relative to the axis z.
[0089] In some implementations, the reflector element 584 includes
a plate having a width that spans the width L of the light guide
luminaire module 302 along the x-axis and a length of 5, 10 or 15
cm, for instance. In some cases, the reflector element 584 is flat.
In other cases, the reflector element 584 can be concave or convex.
Moreover, the reflector element 584 can be formed from or coated
with a reflective metal, e.g., Al, Ag, etc. In other cases, the
reflector element 584 can be coated with reflective dielectric
layers. As such, the reflector element 584 can be configured to
reflect 95% or more of the light output by the light shaping
optical article 340 that is incident onto the reflector element
584. Further, the reflector element 584 can be configured to
specularly reflect incident light. Furthermore, the reflector
element 584 can be configured to diffusely reflect incident light.
In the latter cases, a diffusion pattern can be imprinted on or
within the reflector element 584. Alternatively, a diffusion
pattern can be provided as a film deposited on the reflector
element 584. The degree of diffusion relative to the light incident
on the reflector element 584 may be limited to a predetermined
angular range of the light reflected therefrom.
[0090] In the example illustrated in FIG. 5A, the reflector support
582 is attached to a bottom fraction of one of the side surfaces of
the light guide 330 that is on the same side of the light guide as
the concave first side surface 346 of the light shaping optical
article 340. In the example illustrated in FIG. 5B, the reflector
support 582 can be attached to a side surface or opposing end
surfaces (that are parallel to the y-z plane) of the light guide
330 or the light shaping optical article 340, for example. Further
attachment configurations are described below. The reflector
support may extend over a bottom fraction of the light guide 330
and/or the light shaping element 340 which can cover 10, 30 or 50%
of D, for instance. The reflector support 582 and the reflector
element 584 are rotatably coupled to each other at the pivot 585
which is located adjacent to the intersection of the concave first
side surface 346 and the convex output surface 344 of the light
shaping optical article 340.
[0091] Further in the example illustrated in FIG. 5B, the
illumination device 500 includes a rail 560 arranged and configured
to support the light guide luminaire module 302. Here, the rail 560
has a U profile in the (y,z) plane and is elongated along the
x-axis. A surface of the rail 560 that is parallel to the (x,y)
plane is disposed adjacent to the substrate 305 of the light guide
luminaire module 302, and surfaces of the rail 360 that are
parallel to the (x,z) plane are coupled to the side surfaces of the
light guide 330 along a top fraction of the length D of the light
guide 330. The top fraction can be 10, 30 or 50% of D, for
instance. In some implementations, one of the surfaces of the rail
560--that is on the same side of the light guide 330 as the concave
first side surface 346 of the light shaping optical article
340--can extend over a larger fraction of the light guide than the
opposing rail surface. The former is referred to as an extended
rail surface 562. In some cases, the extended rail surface 562 can
extend over the entire length D of the light guide 330 and the
entire length of the concave first side surface 346 of the light
shaping optical article 340. In such cases, the extended rail
surface 562 is used as the reflector support 582: Here, the pivot
585 can be placed at the end of the extended rail surface 562 and
the reflector element 584 can be connected to the extended rail
surface 562 at the pivot 585. Such a case is described below in
connection with FIG. 6A.
[0092] FIG. 5C shows a light intensity distribution 101'' of the
light output by the illumination device 500 in the (y-z) plane.
Note that the z-axis is parallel to the light guide 330. In some
implementations, the z-axis can be aligned along a target surface
190, e.g., along a wall. A lobe 145' of the light intensity
distribution 101'' represents the light output by the illumination
device 500 in the modified output angular range 145'. A bisector of
the lobe 145' corresponds to the prevalent propagation direction of
light the modified output angular range 145'. Here, the bisector of
the lobe 145' is tilted by a tilt angle
.alpha.+.phi..apprxeq.50.degree. relative to the z-axis. For
example, .phi..apprxeq.10.degree. represents the tilt of the
prevalent propagation direction of the output light in the modified
output angular range 145' relative to the prevalent propagation
direction of the output light in the output angular range 145 as
caused by the reflector element 584 tilted at an angle
.phi./2.apprxeq.5.degree., and .alpha..apprxeq.40.degree.
represents the tilt of the prevalent propagation direction of the
output light in the output angular range 145 relative to the z-axis
as caused by the light shaping optical article 340. A width at
half-max of the lobe 145' corresponds to the divergence of light
the modified output angular range 145'. Here, the width at half-max
of the lobe 145' has a value of about 20.degree..
[0093] An illumination system that includes the illumination device
500 can be recessed in a ceiling at a desired distance from the
target wall to operate as a wall wash. Moreover, the illumination
device 500 can be combined with the illumination device 300 into a
wall wash luminaire as described below.
(v) Wall Wash Luminaire Based on Illumination Device(s) with Light
Guide Luminaire Module, Hinging Element and Adjustable-Orientation
Reflector
[0094] FIG. 6A is a block diagram of an example of an illumination
system 600 based on one or more illumination devices, each of which
includes a light guide luminaire module 302, a hinging element 350
and an adjustable-orientation reflector 580. In this example, the
illumination device is implemented as a combination the
illumination device 300 described above in connection with FIGS.
3A-3B and the illumination device 500 described above in connection
with FIGS. 5A-5B. The illumination system 600 further includes a
housing 494 to support the illumination device(s) at a
predetermined distance (e.g., along the y'-axis) from a target
surface 490 (e.g., a wall, panel, etc.) In the example illustrated
in FIG. 6A, the housing 494 of the illumination system 600 is
recessed inside a ceiling 492. Further in this example, the ceiling
492 and the wall 490 are respectively orthogonal and parallel to
the z'-axis. The illumination system 600 also includes a mount 470
to attach the illumination device(s) to the fixture 494. In this
example, the mount 470 is aligned parallel to the wall 490, along
the z'-axis. Moreover, the illumination system 600 can be arranged
in any of the arrangements (i), (ii) or (iii) described above in
connection with FIGS. 4B-4D.
[0095] Each of the illumination devices of the illumination system
600 includes a rail 560 that supports the light guide luminaire
module 302. The rail can also extend across multiple illumination
devices, for example. The light guide luminaire module 302 includes
a light guide 330 and a light shaping optical article 340. Here,
the light shaping optical article 340 can be implemented as the
light shaping optical article 240 described above in connection
with FIGS. 2A-2F, for example. In the example illustrated in FIG.
6A, the rail 560 has an extended rail surface 562 which extends
over the entire length of the light guide 330 and the entire length
of the concave first side surface of the light shaping optical
article 340. A first hinging portion of the hinging element 350 is
attached to the extended rail surface 562. A second hinging portion
of the hinging element 350 is attached to the mount 470. The pivot
355 of the hinging element 350 orients the light guide 330 (which
is parallel to the z-axis) at a tilt angle .theta. relative the
z'-axis. Here, the extended rail surface 562 also is used as a
reflector support of the adjustable-orientation reflector 580. In
this manner, the pivot 585 of the adjustable-orientation reflector
580 is located at a distal end of the extended rail surface 562
adjacent to an intersection of the concave first side surface and
the convex output surface of the light shaping optical article 340.
The pivot 585 orients the reflector element 584 of the
adjustable-orientation reflector 580 at an angle .phi./2 relative
the light guide 330 (which is parallel to the z-axis).
[0096] In this manner, the light shaping optical article 340 tilts
the guided light (which is tilted relative the z'-axis by a tilt
angle .theta.) by an additional tilt angle .alpha. (relative the
z-axis) for a total tilt angle .theta.+.alpha. relative the z'-axis
of the prevalent propagation direction of the light output by the
light shaping optical article 340. Further, the reflector element
584 (which is tilted by an angle .phi./2 relative the z-axis) bends
the light output by the light shaping optical article 340 (which is
tilted by an angle .alpha. relative the z-axis) by an extra tilt
angle .phi. (relative the z-axis). In this manner, a prevalent
propagation direction (represented by dashed-line) of light output
by the illumination system 600 is tilted by an angle
.theta.+.alpha.+.phi. relative to the z'-axis.
[0097] The light guide luminaire module 302, the hinging element
350, the adjustable-orientation reflector 580, as well as the
housing 494, are elongated along the x-axis. A position of the
housing 494 can vary relative the wall 490. In this manner, a
distance along y'-axis between output surface of the light shaping
optical article 340 and the wall 490 is d'.
[0098] Moreover, a position of the mount 470 along a side surface
of the housing 494 can be adjusted using an adjustment element I/O,
such that the reflector element 584 is fully recessed inside the
housing 494 relative to a level of the ceiling 492 or is partially
protruding below the level of the ceiling 492. For example, half of
the length of the reflector element 584 can protrude below the
level of the ceiling 492. The adjustment element I/O can include
linear displacement actuators for adjusting a distance z' from the
level of the ceiling 492 in increments of .DELTA.z=0.1, 0.5, or 1
cm. In some implementations of the illumination system 600 in which
the reflector element 584 is fully recessed inside the housing 494
relative to a level of the ceiling 492, an opening of the housing
494 can be covered with a transparent cover, that is even with the
ceiling 492, to protect the components of the illumination system
from dust and/or other air-borne debris.
[0099] FIG. 6B shows a light intensity distribution 101''' of the
light output by the illumination system 600 in the (y'-z') plane.
Note that the z'-axis is parallel to the mount 470 and the light
guide 330 is tilted by a tilt angle .theta. relative to the
z'-axis. In some implementations, the z'-axis can be aligned along
a target surface 190, e.g., along a wall. A lobe 145' of the light
intensity distribution 101''' represents the light output by the
illumination system 600 in the modified output angular range 145'.
A bisector of the lobe 145' corresponds to the prevalent
propagation direction of light the modified output angular range
145'. Here, the bisector of the lobe 145' is tilted by a tilt angle
.theta.+.alpha.+.phi..apprxeq.55.degree. relative to the z-axis.
For example, .theta..apprxeq.5.degree. represents the tilt of the
prevalent propagation direction of the guided light in the third
angular range 135 relative to the z'-axis as caused by the pivot
355, .alpha..apprxeq.40.degree. represents the tilt of the
prevalent propagation direction of the output light in the output
angular range 145 relative to the prevalent propagation direction
of the guided light in the third angular range 135 as caused by the
light shaping optical article 340, and .phi..apprxeq.10.degree.
represents the tilt of the prevalent propagation direction of the
output light in the modified output angular range 145' relative to
the prevalent propagation direction of the output light in the
output angular range 145 as caused by the reflector element 584
tilted at an angle .phi./2.apprxeq.5.degree.. A width at half-max
of the lobe 145' corresponds to the divergence of light the
modified output angular range 145'. Here, the width at half-max of
the lobe 145' has a value of about 20.degree..
[0100] Samples of the illumination devices 300 and 500 and of the
illumination systems 400 and 600 have been fabricated and
experiments have been conducted to evaluate their respective
performance. Some of these experiments are summarized below.
(vi) Experimental Results
[0101] Wall wash luminaires corresponding to the illumination
system 400 and the illumination system 600 were used to illuminate
a wall that has a height of H=10'. The housing 494 of the
illumination systems 400 and 600 were placed at various distances
from the wall: d'=12'', 18'' and 24''. These distances are also
referred to as setback distances. Moreover, the performance of the
illumination systems 400 and 600 was evaluated in each of the
arrangements (i), (ii) and (iii) as shown in FIGS. 4B, 4C and 4D,
respectively.
[0102] The LEEs 310 of the light guide luminaire modules 302 used
in the illumination systems 400 and 600 were implemented as Luxeon
Z LEDs: 3500K, 110 lm/W. The convex output surface 344 of the light
shaping optical article 340 was covered with a diffuse film
implemented as Brightview M PR05.TM.. A width of the light guide
luminaire modules 302 along the x-axis was L=60 cm.
[0103] Performance of the illumination systems 400 and 600 was
simulated using a Lumileds rayfile with 2 million rays. Also, an
assumption was used of 20% Lambertian scatter off the floor
underneath the housing 494, in front of the wall 190.
[0104] Experimental results for illumination systems 400 and 600
placed at a setback distance d'=12'' are summarized in Table 6.
TABLE-US-00006 TABLE 6 Tilt .theta. (.degree.) Illumi- caused by
Floor Wall nation Arrange- hinging Uni- illumination illumination
system ment element 350 formity (lm) (lm) 600 (i) 7 5:1 1155 2503
600 (i) 10 10:1 744 2899 600 (i) 14 >10:1 332 3280 400 (i) 7 6:1
1311 2327 600 (iii) 7 <4:1 5785 12517 600 (ii) 7 <4:1 3467
7504 Note that, if the housing was placed at a setback distance d'
= 12'', illumination systems 400 and 600 were optimized to provide
wall washing with best uniformity when the light guide 330 of the
light guide luminaire module 302 was tilted at a tilt angle .theta.
= 7.degree. relative to a target wall surface.
[0105] Experimental results for illumination systems 400 and 600
placed at a setback distance d'=18'' are summarized in Table 7.
TABLE-US-00007 TABLE 7 Tilt .theta. (.degree.) Illumi- caused by
Floor Wall nation Arrange- hinging Unifor- illumination
illumination system ment element 350 mity (lm) (lm) 600 (i) 7
<3:1 1602 2062 600 (i) 10 3:1 1121 2530 600 (i) 14 8:1 595 3028
400 (i) 7 5:1 1760 1881 600 (iii) 7 2:1 8028 10308 600 (ii) 7 2:1
4809 6179 Note that, if the housing was placed at a setback
distance d' = 18'', illumination systems 400 and 600 were optimized
to provide wall washing with best uniformity when the light guide
330 of the light guide luminaire module 302 was tilted at a tilt
angle .theta. = 10.degree. relative to a target wall surface.
[0106] Experimental results for illumination systems 400 and 600
placed at a setback distance d'=24'' are summarized in Table 8.
TABLE-US-00008 TABLE 8 Tilt .theta. (.degree.) Illumi- caused by
Floor Wall nation Arrange- hinging Unifor- illumination
illumination system ment element 350 mity (lm) (lm) 600 (i) 7 2:1
2017 1720 600 (i) 10 2:1 1560 2150 600 (i) 14 3:1 925 2735 400 (i)
7 5:1 2175 1545 600 (iii) 7 2:1 10105 8570 600 (ii) 7 3:1 6059 5135
Note that, if the housing was placed at a setback distance d' =
24'', illumination systems 400 and 600 were optimized to provide
wall washing with best uniformity when the light guide 330 of the
light guide luminaire module 302 was tilted at a tilt angle .theta.
= 14.degree. relative to a target wall surface.
[0107] It was observed that, while using the same arrangement (i),
the illumination system 600 (with an adjustable orientation
reflector 580) provided similar wall wash uniformity as the
illumination system 400 (without an adjustable orientation
reflector 580). However, the illumination system 600 provided
better fill close to the ceiling than the illumination system
400.
[0108] The above experimental summary shows that uniformity better
than 6:1 can be achieved, for both illumination systems 400 and 600
regardless of setback distance and/or arrangement (i), (ii) or
(iii), by adjusting the tilt .theta. of the light guide 330 of the
light guide luminaire module 302 relative to a target wall surface.
Moreover, efficiencies larger than 90% have been achieved for both
illumination systems 400 and 600 for various combinations of
setback distance and/or arrangement (i), (ii) or (iii).
[0109] More detailed results of the noted experiments are described
below.
Experimental Results for Illumination System 400
[0110] FIG. 7A/7B/7C shows an illuminance (x,z')-contour plot
702-a/702-b/702-c of a 10'-wall illuminated by illumination system
400 in arrangement (i) while the light guide 330 of the light guide
luminaire module 302 is tilted at a tilt angle .theta.=7.degree.
relative to the wall. FIG. 7A/7B/7C also shows a z'-axis
cross-section 704-a/704-b/704-c that represents vertical variation
of the illuminance of the wall through the center of the
illumination system 400, and an x-axis cross-section
706-a/706-b/706-c that represents horizontal variation of the
illuminance of the wall at half height.
[0111] In the example shown in FIG. 7A, the setback distance is
d'=12''. Here, the light intensity on a floor in front of the wall
(underneath the housing 494 of the illumination system 400) is
about 1300 lm, and the vertical variation of the illuminance
corresponds to a uniformity of 6:1. In the example shown in FIG.
7B, the setback distance is d'=18''. Here, the light intensity on
the floor is about 1750 lm, and the vertical variation of the
illuminance corresponds to a uniformity of 5:1. In the example
shown in FIG. 7C, the setback distance is d'=24''. Here, the light
intensity on the floor is about 2250 lm, and the vertical variation
of the illuminance corresponds to a uniformity of 5:1.
[0112] The foregoing experimental results indicate the vertical
uniformity provided by the illumination system 400 in arrangement
(i) while the light guide 330 of the light guide luminaire module
302 is tilted at a tilt angle .theta.=7.degree. relative to the
wall. If it is desirable to further increase illuminance levels
proximate the ceiling an illumination system with an
adjustable-orientation reflector can be used.
Experimental Results for Illumination System 600
[0113] FIG. 8A/8B/8C shows an illuminance (x,z')-contour plot
802-a/802-b/802-c of a 10'-wall illuminated by illumination system
600 in arrangement (i) while the light guide 330 of the light guide
luminaire module 302 is tilted at a tilt angle .theta.=7.degree.
relative to the wall. Here, at least a portion of the reflector
element 584 of the adjustable-orientation reflector 580 protrudes,
outside of the housing 494, below a level of the ceiling. FIG.
8A/8B/8C also shows a z'-axis cross-section 804-a/804-b/804-c that
represents vertical variation of the illuminance of the wall, and
an x-axis cross-section 806-a/806-b/806-c that represents
horizontal variation of the illuminance of the wall.
[0114] FIG. 9A/9B/9C shows an illuminance (x,y')-contour plot
812-a/812-b/812-c of a floor in front of the 10'-wall illuminated
by the illumination system 600 in same configuration as the one
associated with FIG. 8A/8B/8C. FIG. 9A/9B/9C also shows a y'-axis
cross-section 814-a/814-b/814-c that represents variation of the
illuminance orthogonal to the wall, and an x-axis cross-section
816-a/816-b/816-c that represents variation of the illuminance
parallel to the wall. Here, y'=0 corresponds to a vertical plane
that crosses the convex output surface of the light shaping optical
article 340 of the illumination system 600. As such, in the
coordinate system x-y', the wall is at y'=d'=-12''(or -310 mm) in
the illuminance (x,y')-contour plot 812-a, at y'=d'=-18''(or -450
mm) in the illuminance (x,y')-contour plot 812-b, and at
y'=d'=-24''(or -620 mm) in the illuminance (x,y')-contour plot
812-c.
[0115] In the example shown in FIGS. 8A and 9A, the setback
distance is d'=12''. Here, the light intensity on the floor is
about 1150 lm, and the vertical variation of the illuminance
corresponds to a uniformity of 5:1. In the example shown in FIGS.
8B and 9B, the setback distance is d'=18''. Here, the light
intensity on the floor is about 1600 lm, and the vertical variation
of the illuminance corresponds to a uniformity of 3:1. In the
example shown in FIGS. 8C and 9C, the setback distance is d'=24''.
Here, the light intensity on the floor is about 2050 lm, and the
vertical variation of the illuminance corresponds to a uniformity
of 2:1.
[0116] The foregoing experimental results indicate that the
reflector element 584 beneficially reduces the light intensity on
the floor by about 250 lm and boosts the illuminance in the
vicinity of the ceiling for the illumination system 600 relative to
the illumination system 400. Additionally, the reflector element
584 cuts off the view of the light shaping optical article 340 and,
thus, advantageously causes a reduction in glare of the
illumination system 600 relative to the illumination system 400.
Also note that, this configuration of the illumination system 600
causes the floor illuminance to fade off from the wall (along the
y'-axis), such that for y'.gtoreq.0 (underneath the light shaping
optical article 340 of the illumination system 600 and farther away
from the wall) there is very little illumination.
[0117] FIG. 10A/10B/10C shows an illuminance (x,z')-contour plot
1002-a/1002-b/1002-c of a 10'-wall illuminated by illumination
system 600 in arrangement (i) while the light guide 330 of the
light guide luminaire module 302 is tilted at a tilt angle
.theta.=10.degree. relative to the wall. Here, at least a portion
of the reflector element 584 of the adjustable-orientation
reflector 580 protrudes, outside of the housing 494, below a level
of the ceiling. FIG. 10A/10B/10C also shows a z'-axis cross-section
1004-a/1004-b/1004-c that represents vertical variation of the
illuminance of the wall, and an x-axis cross-section
1006-a/1006-b/1006-c that represents horizontal variation of the
illuminance of the wall.
[0118] In the example shown in FIG. 10A, the setback distance is
d'=12''. Here, the light intensity on a floor in front of the wall
(underneath the housing 494 of the illumination system 600) is
about 750 lm, and the vertical variation of the illuminance
corresponds to a uniformity of 10:1. In the example shown in FIG.
10B, the setback distance is d'=18''. Here, the light intensity on
the floor is about 1100 lm, and the vertical variation of the
illuminance corresponds to a uniformity of 3:1. In the example
shown in FIG. 10C, the setback distance is d'=24''. Here, the light
intensity on the floor is about 1550 lm, and the vertical variation
of the illuminance corresponds to a uniformity of 2:1.
[0119] FIG. 11A/11B/11C/11D shows an illuminance (x,z')-contour
plot 1102-a/1102-b/1102-c/1102-d of a 10'-wall illuminated by
illumination system 600 in arrangement (i) while the light guide
330 of the light guide luminaire module 302 is tilted at a tilt
angle .theta.=14.degree. relative to the wall. In a configuration
associated with FIGS. 11A-11C, at least a portion of the reflector
element 584 of the adjustable-orientation reflector 580 protrudes,
outside of the housing 494, below a level of the ceiling. In
another configuration associated with FIG. 11D, the entire
reflector element 584 of the adjustable-orientation reflector 580
is contained inside the housing 494, above the level of the
ceiling. FIG. 11A/11B/11C/11D also shows a z'-axis cross-section
1104-a/1104-b/1104-c/1104-d that represents vertical variation of
the illuminance of the wall, and an x-axis cross-section
1106-a/1106-b/1106-c/1106-d that represents horizontal variation of
the illuminance of the wall.
[0120] In the example shown in FIG. 11A, the setback distance is
d'=12'' and the reflector element 584 protrudes below a ceiling
level. Here, the light intensity on a floor in front of the wall
(underneath the housing 494 of the illumination system 600) is
about 350 lm, and the vertical variation of the illuminance
corresponds to a uniformity larger than 10:1. In the example shown
in FIG. 11B, the setback distance is d'=18'' and the reflector
element 584 protrudes below the ceiling level. Here, the light
intensity on the floor is about 600 lm, and the vertical variation
of the illuminance corresponds to a uniformity of 8:1. In the
example shown in FIG. 11C, the setback distance is d'=24'' and the
reflector element 584 protrudes below the ceiling level. Here, the
light intensity on the floor is about 900 lm, and the vertical
variation of the illuminance corresponds to a uniformity of 3:1. In
the example shown in FIG. 11D, the setback distance is d'=24'' and
the reflector element 584 is fully recessed, above the ceiling
level. Here, the light intensity on the floor is not significantly
different relative to the light intensity corresponding to the
configuration of the illumination system 600 associated with FIG.
11C. Also, the uniformity of the illuminance along the z'-axis is
similar to the uniformity corresponding to the configuration of the
illumination system 600 associated with FIG. 11C.
[0121] As such, when desired, the illumination system 600 can be
used as a wall wash luminaire in a configuration for which the
reflector element 584 is fully recessed, above the ceiling level,
without sacrificing the uniformity of the illuminance of wall.
[0122] FIG. 12A/12B/12C shows an illuminance (x,z')-contour plot
1202-a/1202-b/1202-c of a 10'-wall illuminated by illumination
system 600 in which the light guide 330 of the light guide
luminaire module 302 is tilted at a tilt angle .theta.=7.degree.
relative to the wall, when the setback distance is d'=12''. Here,
at least a portion of the reflector element 584 of the
adjustable-orientation reflector 580 protrudes, outside of the
housing 494, below a level of the ceiling. FIG. 12A/12B/12C also
shows a z'-axis cross-section 1204-a/1204-b/1204-c that represents
vertical variation of the illuminance of the wall through the
center of the illumination system, and an x-axis cross-section
1206-a/1206-b/1206-c that represents horizontal variation of the
illuminance of the wall at half height.
[0123] In the example shown in FIG. 12A, the illumination system
600 is configured in arrangement (i). Here, the vertical variation
of the illuminance corresponds to a uniformity of 5:1. In the
example shown in FIG. 12B, the illumination system 600 is
configured in arrangement (ii). Here, the vertical variation of the
illuminance corresponds to a uniformity of 4:1. In the example
shown in FIG. 12C, the illumination system 600 is configured in
arrangement (iii). Here, the vertical variation of the illuminance
corresponds to a uniformity of 4:1.
[0124] FIG. 13A/13B/13C shows an illuminance (x,z')-contour plot
1302-a/1302-b/1302-c of a 10'-wall illuminated by illumination
system 600 in which the light guide 330 of the light guide
luminaire module 302 is tilted at a tilt angle .theta.=7.degree.
relative to the wall, when the setback distance is d'=18''. Here,
at least a portion of the reflector element 584 of the
adjustable-orientation reflector 580 protrudes, outside of the
housing 494, below a level of the ceiling. FIG. 13A/13B/13C also
shows a z'-axis cross-section 1304-a/1304-b/1304-c that represents
vertical variation of the illuminance of the wall through the
center of the illumination system, and an x-axis cross-section
1306-a/1306-b/1306-c that represents horizontal variation of the
illuminance of the wall at half height.
[0125] In the example shown in FIG. 13A, the illumination system
600 is configured in arrangement (i). Here, the vertical variation
of the illuminance corresponds to a uniformity of 3:1. In the
example shown in FIG. 13B, the illumination system 600 is
configured in arrangement (ii). Here, the vertical variation of the
illuminance corresponds to a uniformity of 2:1. In the example
shown in FIG. 13C, the illumination system 600 is configured in
arrangement (iii). Here, the vertical variation of the illuminance
corresponds to a uniformity of 2:1.
[0126] FIG. 14A/14B/14C shows an illuminance (x,z')-contour plot
1402-a/1402-b/1402-c of a 10'-wall illuminated by illumination
system 600 in which the light guide 330 of the light guide
luminaire module 302 is tilted at a tilt angle .theta.=7.degree.
relative to the wall, when the setback distance is d'=24''. Here,
at least a portion of the reflector element 584 of the
adjustable-orientation reflector 580 protrudes, outside of the
housing 494, below a level of the ceiling. FIG. 14A/14B/14C also
shows a z'-axis cross-section 1404-a/1404-b/1404-c that represents
vertical variation of the illuminance of the wall through the
center of the illumination system, and an x-axis cross-section
1406-a/1406-b/1406-c that represents horizontal variation of the
illuminance of the wall at half height.
[0127] In the example shown in FIG. 14A, the illumination system
600 is configured in arrangement (i). Here, the vertical variation
of the illuminance corresponds to a uniformity of 3:1. In the
example shown in FIG. 14B, the illumination system 600 is
configured in arrangement (ii). Here, the vertical variation of the
illuminance corresponds to a uniformity of 3:1. In the example
shown in FIG. 14C, the illumination system 600 is configured in
arrangement (iii). Here, the vertical variation of the illuminance
corresponds to a uniformity of 2:1.
[0128] Some components of light guide luminaire modules used in the
illumination devices 300 and 500 are described below.
(vii) Components of Light Guide Luminaire Modules
[0129] Referring again to FIGS. 3A-3B, a light guide luminaire
module 302 includes a substrate 305 having a plurality of LEEs 310
distributed along a first surface of the substrate 305. The
substrate 305 with the LEEs 310 is disposed at a first (e.g.,
upper) edge of a light guide 330. Sections through the light guide
luminaire module 302 parallel to the y-z plane are referred to as
the "cross-section" or "cross-sectional plane" of the light guide
luminaire module. Also, light guide luminaire module 302 extends
along the x-direction, so this direction is referred to as the
"longitudinal" direction of the light guide luminaire module.
Implementations of the light guide luminaire module 302 can have a
plane of symmetry parallel to the x-z plane, be curved or otherwise
shaped. This is referred to as the "symmetry plane" of the
luminaire module.
[0130] Multiple LEEs 310 are disposed on the first surface of the
substrate 305. For example, the plurality of LEEs 310 can include
multiple white LEDs. In the example illustrated in FIG. 3B, the
LEEs 310 are optically coupled with one or more optical couplers
320. A light shaping optical article 340 is disposed at second
(e.g., lower) edge of light guide 330.
[0131] Substrate 305, light guide 330, and light shaping optical
article 340 extend a length L along the x-direction, so that the
light guide luminaire module 302 is an elongated luminaire module
with an elongation of L that may be about parallel to a wall of a
room (e.g., a ceiling of the room). Generally, L can vary as
desired. Typically, L is in a range from about 1 cm to about 200 cm
(e.g., 20 cm or more, 30 cm or more, 40 cm or more, 50 cm or more,
60 cm or more, 70 cm or more, 80 cm or more, 100 cm or more, 125 cm
or more, or, 150 cm or more).
[0132] The number of LEEs 310 on the substrate 305 will generally
depend, inter alia, on the length L, where more LEEs are used for
longer luminaire modules. In some implementations, the plurality of
LEEs 310 can include between 10 and 1,000 LEEs (e.g., about 50
LEEs, about 100 LEEs, about 200 LEEs, about 500 LEEs). Generally,
the density of LEEs (e.g., number of LEEs per unit length) will
also depend on the nominal power of the LEEs and illuminance
desired from the luminaire module. For example, a relatively high
density of LEEs can be used in applications where high illuminance
is desired or where low power LEEs are used. In some
implementations, the light guide luminaire module 302 has LEE
density along its length of 0.1 LEE per centimeter or more (e.g.,
0.2 per centimeter or more, 0.5 per centimeter or more, 1 per
centimeter or more, 2 per centimeter or more). The density of LEEs
may also be based on a desired amount of mixing of light emitted by
the multiple LEEs. In implementations, LEEs can be evenly spaced
along the length, L, of the light guide luminaire module 302. In
some implementations, a heat-sink can be attached to the substrate
305 to extract heat emitted by the plurality of LEEs 310. The
heat-sink can be disposed on a surface of the substrate 305
opposing the side of the substrate 305 on which the LEEs 310 are
disposed. The light guide luminaire module 302 can include one or
multiple types of LEEs, for example one or more subsets of LEEs in
which each subset can have different color or color
temperature.
[0133] Optical coupler 320 includes one or more solid pieces of
transparent optical material (e.g., a glass material or a
transparent plastic, such as polycarbonate or acrylic) having side
surfaces positioned to reflect light from the LEEs 310 towards the
light guide 330. In general, side surfaces are shaped to collect
and at least partially collimate light emitted from the LEEs. In
the y-z cross-sectional plane, side surfaces can be straight or
curved. Examples of curved surfaces include surfaces having a
constant radius of curvature, parabolic or hyperbolic shapes. In
some implementations, side surfaces are coated with a highly
reflective material (e.g., a reflective metal, such as aluminum or
silver), to provide a highly reflective optical interface. The
cross-sectional profile of optical coupler 320 can be uniform along
the length L of light guide luminaire module 302. Alternatively,
the cross-sectional profile can vary. For example, side surfaces
can be curved out of the y-z plane. Depending on the illumination
application, mitigation of glare from the output light within the
x-z plane can be important. As such the optical couplers 320 may be
configured to provide respective optical power with the x-z
plane.
[0134] The exit aperture of the optical coupler 320 adjacent the
upper edge of the light guide is optically coupled to edge to
facilitate efficient coupling of light from the optical coupler 320
into light guide 330. For example, the surfaces of a solid coupler
and a solid light guide can be attached using a material that
substantially matches the refractive index of the material forming
the optical coupler 320 or light guide 330 or both (e.g.,
refractive indices across the interface are different by 2% or
less.) The optical coupler 320 can be affixed to light guide 330
using an index matching fluid, grease, or adhesive. In some
implementations, optical coupler 320 is fused to light guide 330 or
they are integrally formed from a single piece of material (e.g.,
coupler and light guide may be monolithic and may be made of a
solid transparent optical material).
[0135] Light guide 330 is formed from a piece of transparent
material (e.g., glass material such as BK7, fused silica or quartz
glass, or a transparent plastic, such as polycarbonate or acrylic)
that can be the same or different from the material forming optical
couplers 320. Light guide 330 extends length L in the x-direction,
has a uniform thickness T in the y-direction, and a uniform depth D
in the z-direction. The dimensions D and T are generally selected
based on the desired optical properties of the light guide (e.g.,
which spatial modes are supported) and/or the direct/indirect
intensity distribution. During operation, light coupled into the
light guide 330 from optical coupler 320 (with an angular range
125) reflects off the planar surfaces of the light guide by TIR and
spatially mixes within the light guide. The mixing can help achieve
illuminance and/or color uniformity, along the y-axis, at the
distal portion of the light guide at the light shaping optical
article 340. The depth, D, of light guide 330 can be selected to
achieve adequate uniformity at the exit aperture of the light
guide. In some implementations, D is in a range from about 1 cm to
about 20 cm (e.g., 2 cm or more, 4 cm or more, 6 cm or more, 8 cm
or more, 10 cm or more, 12 cm or more).
[0136] In general, optical couplers 320 are designed to restrict
the angular range of light entering the light guide 330 (e.g., to
within +/-40 degrees) so that at least a substantial amount of the
light (e.g., 95% or more of the light) is optically coupled into
spatial modes in the light guide 330 that undergoes TIR at the
planar surfaces. Light guide 330 can have a uniform thickness T,
which is the distance separating two planar opposing surfaces of
the light guide. Generally, T is sufficiently large so the light
guide has an aperture at first (e.g., upper) surface sufficiently
large to approximately match (or exceed) the exit aperture of
optical coupler 320. In some implementations, T is in a range from
about 0.05 cm to about 2 cm (e.g., about 0.1 cm or more, about 0.2
cm or more, about 0.5 cm or more, about 0.8 cm or more, about 1 cm
or more, about 1.5 cm or more). Depending on the implementation,
the narrower the light guide the better it may spatially mix light.
A narrow light guide also provides a narrow exit aperture. As such
light emitted from the light guide can be considered to resemble
the light emitted from a one-dimensional linear light source, also
referred to as an elongate virtual filament.
[0137] While optical coupler 320 and light guide 330 are formed
from solid pieces of transparent optical material, hollow
structures are also possible. For example, the optical coupler 320
or the light guide 330 or both may be hollow with reflective inner
surfaces rather than being solid. As such, material cost can be
reduced and absorption in the light guide can be mitigated. A
number of specular reflective materials may be suitable for this
purpose including materials such as 3M Vikuiti.TM. or Miro IV.TM.
sheet from Alanod Corporation where greater than 90% of the
incident light can be efficiently guided to the optical
extractor.
[0138] The light shaping optical article of the light guide
luminaire module 302 is described in detail above, in connection
with FIGS. 1A-1D and 2A-2F.
[0139] The preceding figures and accompanying description
illustrate example methods, systems and devices for illumination.
It will be understood that these methods, systems, and devices are
for illustration purposes only and that the described or similar
techniques may be performed at any appropriate time, including
concurrently, individually, or in combination. In addition, many of
the steps in these processes may take place simultaneously,
concurrently, and/or in different orders than as shown. Moreover,
the described methods/devices may use additional steps/parts, fewer
steps/parts, and/or different steps/parts, as long as the
methods/devices remain appropriate.
[0140] In other words, although this disclosure has been described
in terms of certain aspects or implementations and generally
associated methods, alterations and permutations of these aspects
or implementations will be apparent to those skilled in the art.
Accordingly, the above description of example implementations does
not define or constrain this disclosure. Further implementations
are described in the following claims.
* * * * *