U.S. patent number 3,902,059 [Application Number 05/443,018] was granted by the patent office on 1975-08-26 for light reflector system.
This patent grant is currently assigned to Esquire, Inc.. Invention is credited to Albert C. McNamara, Jr..
United States Patent |
3,902,059 |
McNamara, Jr. |
August 26, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Light reflector system
Abstract
A multi-sided light reflector for a light source, which
reflector incorporates curved reflector surfaces that cooperate
with a light source disposed within the reflector to permit only
primary reflections from the light source to be emitted from a
reflector opening. The reflector includes a plurality of curved
side reflecting surfaces disposed in angular relationship with a
plurality of curved corner reflector surfaces disposed between the
side reflector surfaces and joined to the side reflecting surfaces.
The line of juncture between the side reflector surfaces and the
corner reflector surfaces is curved and the lower point of each of
the corner reflector surfaces is defined by intersection of the
curved lines of juncture of the respective corner reflectors and is
disposed in the plane of the reflector opening. The reflector
opening, from which direct and primary reflections are emitted, is
defined by the primary exit pupil ray of the light source from the
various side and corner reflectors.
Inventors: |
McNamara, Jr.; Albert C.
(Houston, TX) |
Assignee: |
Esquire, Inc. (New York,
NY)
|
Family
ID: |
23759104 |
Appl.
No.: |
05/443,018 |
Filed: |
February 15, 1974 |
Current U.S.
Class: |
362/349 |
Current CPC
Class: |
F21V
7/09 (20130101) |
Current International
Class: |
F21V
7/09 (20060101); F21V 7/00 (20060101); F21V
007/09 () |
Field of
Search: |
;240/1.3,41.35F,41.36,13R,13A,41.35R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Adams, Jr.; Russell E.
Claims
What is claimed is:
1. A light reflector for carrying a mounted light source therein
and having a light emission opening through which light from the
source is emitted, comprising:
first and second curved side reflectors oriented to cause at least
some primary reflections of the source to be emitted through the
opening,
said curved side reflectors meeting at least at a point defining a
first corner at the opening, the primary reflection exit pupil rays
of said light source to said curved side reflectors defining curved
edges of said curved side reflectors, and
a curved corner reflector being defined within said curved edges of
said side reflectors and being oriented relative to said light
source to cause at least some primary reflections of said light
source to be emitted through the opening without further
reflection.
2. A light reflector as described in claim 1, wherein said opening
is defined by a plurality of side reflector surfaces, and
a plurality of substantially identical corner reflectors are
disposed one between each of the respective side reflector
surfaces.
3. A light reflector as described in claim 1, wherein one of the
extremities of each of said plurality of corner reflectors define a
plurality of points, and
a multi-sided generally planar reflector surface is defined by a
plurality of straight lines interconnecting said plurality of
points.
4. A light reflector for carrying a mounted light source therein
and having an opening defined thereby through which light from the
source emanates, said light reflector comprising:
a plurality of curved side reflectors slanted inwardly from the
plane of said opening to cause at least some primary reflections of
the source to emanate through the opening, said side reflectors
being disposed in angulated relation to each other in the plane of
the opening, and
a plurality of corner reflectors being disposed one between each of
said adjacent side reflectors and extending inwardly from the plane
of said opening, said corner reflectors being curved and being
defined by curved lines that intersect at each extremity
thereof.
5. A light reflector as described in claim 4, wherein one of the
points of intersection of said curved lines defining each of said
corner reflectors lies at the points of intersection of said side
reflectors, and
lines interconnecting said points of intersection of said curved
lines coincide with lines defining said opening.
6. A light reflector as recited in claim 5, wherein lines
interconnecting each of the other of the points of intersection of
said curved lines define a generally planar surface of multi-sided
configuration.
7. A light reflector for carrying a mounted light source therein
and having an opening through which light from the source is
emitted, comprising:
at least first and second adjacent curved reflectors meeting to
form a part of said opening through which light from the source is
emitted and being oriented to cause at least some primary
reflections of said light source to be emitted through the opening,
and
a third curved reflector extending from the plane of said opening,
being adjacent at least one of said first and second curved
reflectors and having sides merging toward a point at a corner of
said opening, the exit pupil of each of said two adjacent curved
reflectors permitting the forwardly directed primary light
reflections of said light source from said third curved reflector
to emanate through said opening without secondary reflection.
8. A light reflector as recited in claim 7, wherein
said first and second reflectors define concave reflector surfaces
facing said light source.
9. A light reflector as recited in claim 8, wherein
said third curved reflector is adjacent said first curved reflector
and in spaced relation with said second reflector, such that the
primary reflections from said third curved reflector directed
toward the meeting of said first and second adjacent curved
reflectors define a boundary between said first curved reflector
and said third curved reflector.
10. A light reflector for carrying a mounted light source and
defining an opening through which light from the source is emitted,
comprising,
a plurality of curved side reflectors having lower edges meeting to
form said opening and defining a plane, and
a plurality of curved corner reflectors disposed between at least
some of said curved side reflectors and extending from the plane of
said opening, said corner reflectors having curved sides merging
toward a point located on the plane of said opening and being
oriented to reflect light from said source through said opening,
and
the exit pupil of each of said curved reflectors at said opening
permitting primary light reflections of said light source from each
of said curved corner reflectors to emanate through said opening
without secondary reflection.
11. A light reflector as recited in claim 10, wherein
said plurality of curved side reflectors includes first and second
curved reflectors meeting at said opening, and
said plurality of curved corner reflectors includes a reflector
adjacent said first curved reflector but spaced from said second
reflector, such that the forwardly directed primary reflections
from said curved corner reflector directed toward the meeting of
said first and second curved reflectors define a boundary between
said first curved reflector and said curved corner reflector.
12. A light reflector as described in claim 11, wherein
said plurality of successively adjacent curved reflectors includes
a third curved reflector meeting with said first reflector at said
opening, and
said plurality of curved corner reflectors includes a second corner
reflector adjacent said first curved reflector but spaced from said
third curved reflector, such that the forwardly directed primary
reflections from said second curved corner reflector directed
toward the meeting of said first and third curved reflectors define
a boundary between said first curved reflector and said second
curved corner reflector.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates generally to lighting reflectors and more
specifically to such reflectors having multi-sided reflecting
surfaces causing at least some primary reflections to be emitted
through the opening of the reflector.
2. DESCRIPTION OF THE PRIOR ART
It has long been standard to equip light bulbs, both incandescent
and vapor types, with reflectors to concentrate light in a
generally desired direction.
The most efficient of these prior art reflectors are those
reflectors which are concave in shape so as to permit all light
emanating from the light and reflector system to be either the
direct light from the source or to be the primary reflective light.
Primary reflective light is that light which is reflected only once
from the source before the light is emitted from the light and
reflector system. Such a light and reflector system that typifies
this arrangement is the ordinary flash-light reflector which is
typically of hyperbolic internal configuration.
Fabrication of curved surfaces, however, has in the past been
considered to make the use of such reflectors extremely expensive
in many applications, particularly in systems where the reflectors
are somewhat large, as for mounting mercury vapor lamps.
Heretofore, flat-sided reflectors slanting backwardly from the
opening have been used in such applications, usually presenting a
rectangular or square opening through which much of the primary
reflections are emitted. Such reflectors are relatively cheap to
fabricate and assemble. However, not all of the reflections from
such a reflector system are primary reflections and therefore there
is great loss in efficiency. For instance, all light which is not
reflected initially forward is not emitted before being reflected
at least a second time. Further, even forward reflected light which
is cut off by the exit pupil of the reflector must be reflected at
least a second time before emission. Finally, no light directed at
the corners, either direct or from a primary reflection, is emitted
from the reflector without undergoing at least secondary
reflection.
Lack of light reflection from the corner of square reflectors has
resulted in the use of corner inserts. The conventional method of
modifying a square-shaped reflector to provide corner reflectors is
to use inserts which start at a point at the corner of a square
base of the reflector and flares so that at the opening the insert
is at its widest dimension. Such a structure effectively changes
the square opening into a reduced sized octogan opening and hence
creates "dead" corner spaces which are not useful reflection
surfaces.
It is therefore a feature of this invention to provide an improved
lighting reflector system comprised of multi-sided curved reflector
segments that provide optimum direct and primary reflections.
It is another feature of this invention to provide an improved
lighting reflector having curved corner reflector surfaces therein
that utilize the space of the reflector to an optimum degree and
produce more efficient direct and primary reflection emissions than
from prior art flat-sided or hyperbolic reflectors.
SUMMARY OF THE INVENTION
A preferred embodiment of the present invention comprises a light
reflector in which a light source may be installed and in which the
side reflectors are curved, the side reflectors establishing an
opening for light emissions. The side reflectors are oriented
relative to the light source to cause only primary reflection
emissions from the opening. Corner reflectors are disposed between
the side reflectors and are also curved in such manner as to permit
primary reflection from those portions which would otherwise be cut
off by the exit pupil dimension of the side reflectors. The corner
reflectors allow the full dimension of the opening to be
utilized.
The outlet opening of the light reflector is defined by straight
lines lying in each of the curved reflector surfaces, the straight
lines of adjacent side reflecting surfaces being disposed in
angular intersecting relationship and the lowermost point of each
of the corner reflector surfaces being disposed at the intersection
of said straight lines.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-recited features, and various
advantages and objects of the invention which will become apparent,
are attained and can be understood in detail, more particular
description of the invention briefly summarized above may be had by
reference to the embodiments thereof which are illustrated in the
appended drawings, which drawings form a part of this
specification. It is to be noted, however, that the appended
drawings illustrate only typical embodiments of the invention and
are therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
In the drawings:
FIG. 1 is a plan view of a prior art lighting reflector.
FIG. 2 is a plan view of a light reflector constructed in
accordance with the present invention.
FIG. 3 is an isometric illustration depicting the light reflector
of FIG. 2.
FIG. 4 is a schematic representation illustrating formation of the
outlet opening of the reflector structure in accordance with the
various reflector orientation thereof.
FIG. 5 is a schematic representation illustrating direct and
primary reflection of light from the light reflector system of the
present invention.
FIG. 6 is an oblique schematic representation for determining the
dimension of corner reflectors.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings and first to FIG. 1, a light
reflector is shown which has previously been preferred for
optimizing light reflections from a reflector having a square
opening. In such a reflector, side pieces 11, 13, 15 and 17 are
slanted back from the opening to terminate in a rectangular base 19
at the back of the reflector which is generally parallel with the
plane of the opening through which the light is emitted. It may be
assumed for purposes of discussion that the reflector is uniformly
dimensioned so that each of the side reflectors are of the same
dimension and base 19 is square.
Were it not for the corner pieces to be described below, the side
pieces would have respectively met each other at corners 21, 23, 25
and 27, respectively (as shown by the dotted lines). Light from a
source located in the center of the reflector and emitting light in
all directions would not reflect light off of a side reflector
through the opening at the corners and therefore a reflector
without corner pieces at all is extremely inefficient in its corner
emissions.
As is shown, increased efficiency can be developed by the insertion
of conventional type corner pieces 29, 31, 33 and 35. Corner piece
21 located between side pieces 11 and 13 is in the shape of an
isosceles triangle. The corner between the two equal length sides
is secured at a corner of base 19 and the other two corners
terminate at the plane of the opening, one corner with adjacent
side piece 11 and the other corner with adjacent side piece 13,
each being displaced at the opening an equal distance from corner
21.
Each of corner pieces 31, 33 and 35 are similar in construction to
corner piece 29. It has been demonstrated that such a structure
with the corner pieces as described is more efficient in its light
emission than a structure without such corner pieces since more
primary emission is developed.
It should be noted that for what was originally a square shaped
reflector opening, the corner pieces have reduced the effective
opening area by the amount of corner spaces 37, 39, 41 and 43.
These spaces are the triangular spaces between the edge of the
corner piece and the edge of the side pieces in the plane of the
opening.
In accordance with the present invention, side reflector surfaces
are developed, as shown in FIG. 4, which reflect primary light from
the source through the reflector opening and which utilize the
entire opening of the reflector.
As may be shown in FIG. 4, a theoretical point source is located at
O having an image I with respect to side 50. That is, a right angle
projection from point O to a plane that is tangent to the curved
reflector 50 results in point I being established an equal distance
from the point of tangency of the plane and the curved reflector
surface but on the opposite side thereof from point O. As may be
shown in FIG. 4, a cross-sectional view of the plane 48 that is
tangent to the curved surface 50 shows clearly the right angle
relationship between the plane 48 and the projection line,
O-to-I.
As previously explained, the exit pupil is the edge of the opening
on one side of which primary reflections from a light source are
allowed to pass and on the other side of which light rays are
blocked. The exit pupil ray, therefore, is a ray along the line
drawn between point I and the escape edge of the opening. The exit
pupil edge is identified with reference numeral 52.
Now turning to FIG. 6, it is illustrated that the exit pupil rays
from point I which are allowed to escape past opposite side 54
after being reflected from side 50 are allowed to escape at corner
56 and corner 58 of side 54 in the plane of the opening. Of course,
rays also escape at all points between corners 56 and 58 along exit
pupil edge 52.
Exit pupil rays are also permitted to escape from side 60 adjacent
side 50 at corner 62 between sides 50 and 60 in the plane at the
opening and along the edge between corners 62 and 56.
It will be seen that there are rays within an angle .phi. which are
not permitted to be emitted through the opening without being
further reflected from side piece 60. This angle may be determined
by drawing a line from image point I to corner 56, marking the
intersection point 64 between that line and plane 50, and then
drawing a straight line from corner 62 through point 64.
In similar fashion it is possible to determine the point analogous
to 64 in FIG. 6 for each tangent plane such as 48 for curve 50. The
locus of these points determining the curve 81 in FIG. 5.
While FIG. 6 represents straight line calculation of the exit pupil
rays for determination of the outlet opening, such is intended for
purposes of illustration only. Point or line calculations generated
from curved reflector surfaces will function in the same
manner.
Now referring to FIG. 2 in more detail, it will be seen that corner
reflectros may be inserted, each corner reflectors or piece being
defined by two of the 12 curved lines in adjacent side pieces. For
example, corner piece 72a lies between curved side pieces 70a and
70d and is defined by the two curved lines, one on each side piece,
drawn to the common corner between side pieces 70a and 70d. As
shown in FIG. 2, corner pieces 70a, 70b, 70c, 70d, 70e and 70f and
side pieces 72a, 72b, 72c, 72d, 72e and 72f meet in a six sided
shaped base 74.
Now turning again to FIG. 4, it should be noted that all rays which
are projected at least as forward as the exit pupil ray are allowed
to escape at edge 52 (that is, all rays that are at least as
forward as the ray from point O intersecting plane 48 at tangent
point 80). These rays are all allowed to be emitted through the
opening of the reflector following only a single reflection, a
primary reflection. This point 80 is determined by making the angle
of incidence from point O to plane 48 equal to the angle of
reflection such that the reflected ray passes through point 52. As
is well-known in optical theory, by placing I on the opposite side
of plane 48 from 0, but at the same perpendicular distance
therefrom, a line from I to point 52 intersects plane 48 at point
80. There is no need for the reflecting surface in plane 48 to
extend beyond point 80 for this phenomenon to apply. Each of the
various points lying in the curved reflector surface may be located
graphically by simple determination of the point of tangency
between a plane that is tangent to the surface 50. Moreover, the
curved reflector surface 50 effectively eliminates the necessity
for providing internal back reflectors that would otherwise promote
primary reflection of light rays that are blocked by the escape
edge 52.
It has been demonstrated that the configuration shown in FIG. 2 is
approximately 6 to 10 percent more efficient in emitting light than
the configuration shown in FIG. 1.
If the reflector construction employed only side reflectors that
are joined along curved lines, light reflected by certain edge
portions of the side reflectors will not be capable of primary
reflection. It is therefore desirable to to provide corner
reflectors that are positioned and configured to provide primary
reflection of light that would otherwise become lost or diffused
through multiple reflection. In accordance with FIG. 5 the curved
corner reflector surfaces, such as depicted at 72a through 72f in
FIG. 2 are generated by the various points at which the primary
reflections fail to be reflected by the side reflector surfaces. A
direct ray of light being emitted from point 0', the imaginary
center of the reflector system at which the light source is
located, and passing through a point of tangency of an imaginary
plane intersecting the side reflector surface will pass through the
outlet opening of the reflector structure only if the point of
imaginary reflection from point I' falls outside of a corner area
such as that defined by broken lines. It becomes desirable
therefore, to provide the reflector structure with corner reflector
surfaces that are generated in such manner that the corner
reflectors also provide for primary reflection of light being
emitted from the light source. If each point on the side reflector
surfaces is generated beyond which primary reflections will not
occur, curved lines will be established by the various points, such
as illustrated in broken lines at 81 and 83. Within the areas
defined by the curved lines 81 and 83, corner reflectors may be
disposed, the center of which being oriented in substantially
normal relation to direct ray of light being emitted from the point
0'.
Although particular embodiments of the invention have been shown,
it will be understood that the invention is not limited thereto,
since many modifications may be made and will become apparent to
those skilled in the art. For example, the reflector has been
depicted as being of six sided configuration. The principles
described, however, are also applicable to any other multi-sided
reflector system. Also, each of the curved corner reflector
surfaces have been described as merging in a corner point. In an
actual structure, it may be desired to have that point be a phantom
point for ease of construction, operation of the reflector being
functionally similar to that described.
* * * * *