Note: Descriptions are shown in the official language in which they were submitted.
~z~s
01 Background of the Invention
02 Field of Use
03 This invention relates generally to high intensity high
04 efficiency lighting units comprising a lamp and reflector and to
05 lighting systems using the same. In particular, it relates to
06 reflec-tors for such lighting units and systems.
07 Description of the Prior Art
08 Effective illumination of interior spaces and work
09 surfaces in offices, reception rooms, libraries, homes, and so
forth, requires consideration of the desired distribution of
ll light, area-wise and space-wise, and consideration of the
12 efficiency, location, electromechanical features, and esthetics
13 of the lighting unit itself. High intensity, high efficiency
14 lighting units which provide even light distribution through an
area or on a specific work surface but which do not disturb the
16 vision of a person near the unit are often preferred.
17 It may be desirable, for example, for -the lighting unit
18 to project light downwardly directly onto a large work area, such
l9 as a room, or onto a small work surface, such as a desk. Or, it
may be desirab]e that the lighting unit projec-t light upwardly
21 for reflection downwardly from the ceiling for general light
22 purposes. In any case, the light should be distributed as evenly
23 and as efficiently as possible over an area of predetermined size
2~ and shape. Also, the lighting unit, however mounted, should be
at an elevation close enough to illuminat0 the area effectively
26 and efficiently, and if such elevation is near -the eye level of a
27 person nearby, the unit should be designed so that the person can
28 be quite close to the lighting unit without seeing the lamp or
29 its rerlection.
- 2 -
01 U.~. Patent 3,389,246 shows a lighting unit located
02 near eye level of a standing person for simultaneously directing
03 light downwardly onto a work surface and upwardly for reflection
04 from the ceiling. In one embodiment, the ligh-ting unit includes
05 a fluorescent lamp tube and employs louvered devices or baffle
06 deflectors for directing the light upwardly and downwardly and
07 for preventing glare from disturbiny a person standing or sitting
08 in the room. In another embodiment, the louvered devices are
09 omitted and three reflectors are provided, namely, two
spaced-apart downwardly curved reflectors above the lamp and
11 between which l~ght projects upwardly directly from the lamp to
12 the ceiling, and an upwardly curved reflector below the lamp for
13 reflecting light from the lamp upwardly to the aforementioned two
14 reflectors for subsequent downward reflection by the latter onto
the work surface.
16 U.S. Patent 3,746,854 discloses a lighting unit or
17 luminair employing a lamp, such as an incandescent lamp, a gas
18 discharge light, or a fluore~cent light, in conjunction with a
19 reflector or specified configuration which provides for a precise
distribution of light over a precise relatively wide area
21 outdoors.
22 However, disposition of louvers, baffles, reflectors,
23 and the like in a light path for directional control and use of
24 incandescent and ~luorescent lights impair lighting efficiency.
Furthermore, some prior art reflectors, designed to achieve
26 certain directional and distribution effects, do so at the
27 expense of overall lighting efficiency, even though
28 high-intensity lamps, such as metal halide and high-pressure
29 sodium lamps, are used in conjunction with reflectors made of
specular materials.
31
~3Z~
01 Summary of the Present_Invention
02 A lighting unit in accordance with the present
03 invention comprises a lamp and a reflector and is advan-tageously
04 employed in a variety of lighting systems -to provide high
05 intensity, high efficient, even illumina-tion over an area or work
06 surface of particular size and shape and has a preferred cut-off
07 angle to enable a person to work or approach relatively close to
08 the lighting unit without seeing the lamp or lamp reflection.
~Q9 The reflector comprises at lea~t two reflector segments
~10 (such as side segments loca-ted on cpposite sides of the lamp
11 axis), each having spaced apart first and second edges and a
12 reflector surface between those edges. The outer edges of the
~13 two reflector segments are spaced apart Erom each other and are
14 located in a front plane on the front side of the lamp, which
front plane coincides with or defines the reflector opening. The
16 inner edges of the two reflector segments are adjacent each
17 other, joining toge-ther at their rear edges along a line behind
~18 the lamp in a rear plane on the rear side of and spaced from the
19 lamp. Each point on a curve defined by a cross-section plane
extending transverse to the lamp axis and intersecting the
~21 reflector surface of a reflector segment, is spaced further away
22 from the lamp than the rear edge of that reflector segment. Some
23 points on this curve are located on that side of the rear plane
24 which is remote from the lamp. This arrangement enables light
emanating from the rear of the lamp to be reflected by the rear
26 of the reflector to side portions of the reflector and from
27 thence out of the reflector, thereby enhancing light efficiency.
28 In one lighting system disclosed, one embodiment of the
29 lighting unit is mounted so as -to project light upwardly for
downward reflection from a ceiling onto a work area or work
31 surface therebelow and the reflector opening
32 _ ~ _
l~Z~
01 is at or near eye level of a standing person. The lamp, which
02 provides relatively high lumens per watt of electrical energy,
03 such as a mercury metal halide or a high-pressure sodium lamp,
04 includes an elongated glass envelope of circular cross section
05 surrounding a light sourcP therewithin. The reflector, which is
06 fabricated of one or more pieces of specular reflective material,
07 comprises eight interrelated curved reflector segments including:
08 two side segments of the type hereinbefore described and located
09 on opposite sides of the lamp and joined together along a line
behind the lamp to reflect light emitted from the rear of the
11 lamp; two end segments at opposite ends of the lamp; and four
12 corner segments, each loca~ed between a side reflector and an end
13 reflector. The said one embodiment, which employs the
14 aforedescribed pair of side segments, also employs a pair of
oppositely disposed spaced apart end segments, and two pairs of
16 oppositely disposed spaced apart corner segments. Each of these
17 segments has spaced apart outer and inner edges and a curved
18 reflector surface therebetween, and each outer edge lies in an
19 aforementioned ront plane. The inner edges of the end and
corner segments extend behind the lamp. Each point on a curve
21 defined by a cross-section plane which is tranverse to the lamp
22 axis and intersects the curved reflector surface of an end or
23 corner segment, is spaced farther from the lamp than the inner
24 edge of the segment. The reflector and lamp cooperate to project
light from the reflector opening in a generally circular pat-tern
26 of even intensity and high efficiency at a cut-off angle of 35
27 with respect to a plane in which the reflector opening lies, in a
28 highly efficient mannter. The said one embodiment of the
29 lighting unit can also be used to project light downwardly or
horizontally, if desired.
31 - 5 -
~z~
01 In a second lighting system disclosed, a second
02 embodiment of a ligh-ting uni-t in accordance with the invention
03 and employing a fluorescen-t tube is mounted so as to project
04 light directly downwardly onto a work surface such as a desk or
05 table top and the lighting unit is located so that the reflector
06 opening is at or near the eye level of a person seated nearby.
07 In this system, the lighting unit is located at a side of the
08 desk. If preferred, two such lighting units can be located at
09 opposite sides of the desk.
In a third lighting system disclosed, a third
11 embodiment of a lighting unit, somewhat similar to the second
12 embodiment but employing a pair of fluorescent tubes and a
13 reflector therefor in accordance with the invention is provided.
14 In the said one embodiment, the curved reflector
surfaces of the two side segments are of the same length and
16 symmetrical. In the second and -third embodiments, only two
17 curved reflector surfaces are employed for each lamp and the two
18 surfaces are not symmetrical and one is longer than the other.
19 Lighting units and systems in accordance with the
invention offer several advantages over the prior art. For
21 example, light is distributed area-wise and space-wise, at
22 maximum efficiency and is evenly distributed. Furthermore, if
23 the lighting unit is mounted so as to project light upwardly for
24 reflection from a ceiling and is located so that the reflector
opening is substantially at the eye level of a standing person, a
26 person can approach relatively close to the lighting unit without
27 being subjected to a direct view of the high intensity lamp or
28 its reflection, thereby elimina-ting the need for light directing
29 louvers or baffles which impair illumination efficiency. On the
other hand, if the lighting unit is employed so as to direct
31 light downwardly or laterally at a level which is near the eye
32 level of a seated person,
33 - 6 -
1~2i~
01 a person can be quite close to the lighting unit before the lamp
02 or its reflection become visible. Lighting units in accordanee
03 wi~h the ~nvention employ commercially available readily
04 obtainable lamps and electric power supplied therefor and employ
05 reflectors which are easily and economically fabricated, either
06 as one-piece units by vacuum from a suitable plastic material, or
07 in discrete reflector segments which can be cut, shaped, and
08 assembled from suitable specular sheet material, such as
09 anodized aluminum or the like. Other objects and advantages of
the invention will hereinafter appear.
11 More particularly, the invention is, in a lighting
12 system, a room having a floor and a ceiling, and a lighting unit
13 comprising a lamp and a reflector comprising a plurality of
14 curved reflector surfaces, -the reflector having an opening in a
frontal plane defined by the edges of the curved reflector
16 surfaces. The lighting unit is mounted so as to project a cone
17 of light emanating from the opening upwardly toward the ceiling
18 for reflection downwardly therefrom, and is located so that the
19 frontal plane is at a distance above the floor which is about
that of the average eye-level of a standing human being. The
21 cone of light defines an angle of about 35 between the edge
-22 thereof and the ~rontal plane.
23 ~RIEF DESCRIPTION OF THE DRAWINGS
24 FIGURE 1 is a perspective view of the upper side of one
embodiment of a lighting unit in accordance with the present
26 invention;
27 FIGURE 2 is a schematic diagram on reduced scale
28 showing a lighting unit according to FIG. 1 employed in a
29 lighting system wherein light from the unit is directed upwardly
for refleetion from a ceiling and wherein the reflector opening
31 of the lighting unit is located near eye level;
32 ~ - 7 -
. "
01 FIGURE 3 is an enlarged top plan view of the interior
02 of the lighting unit shown in FIGS. 1 and 2, with -the ylass cover
03 plate of FIG. 1 removed and shows the lamp and reflector therein;
04 FIGURE 4 is a cross-sectional view on reduced scale
05 taken on line 4-4 of FIG. 3;
06 FIGURE 5 is a cross-sectional view on reduced scale
07 taken on line 5-5 of FIG~ 3;
08 FIGURE 6 is a cross-sectional view on reduced scale
09 taken on line 6-6 of FIG. 3;
11
12
13
14
16
17
18
21
22
23
24
~26
~27
28
29
31
32 - 7a -
,~,,"
~13~
FIGURE 7 is a graph depicting the light distribution pattern and
candle power of the lighting unit shown in FIGS. L through 6,
FIGURE 8 is a perspective view of the lower side of a second
embodiment of a lighting unit in accordance with the present invention
FIGURE 9 is a schematic diagram on reduced scale showing two
lighting units according to FIG. 8 employed in a lighting system wherein
light from the units is directed downwardly onto a work surface and wherein
the reflect.or opening of each lighting unit is located near eye level;
FIGURE lO is a top plan view of the lighting units and worl; surface
10 of FIG, 9;
. FIGURE 11 is a. bot.tom plan view of the interior of the lighting unit
shown in FIGS. 8, 9, and 10, and shows the lamp and reflector therein
:~ .
~ FIGURE 12 is an enLarged cross-sectionaL view taken on line 12-12
- of FIG. IL,
:;
FIGURE 13 is a graph depicting the light distribution pattern and
candle power of the lighting unit shown in FIGS. 8 through 12,
-~ FIGURE 14 is a perspective view of the lower side of a third embodi-
,: .
ment of a lighting unit in accordance with the present invention,
FIGURE 15 is an enlarged cross-sectional view taken on line 15-15
20 of FIG. 14: and
FIGURE 16 is a graph depicting the light distribution pat'ern and
candle power of the Lighting unit sh~ n in FIGS. L4 and 15.
01 Description of Preferred Em~odiments
02 First ~mbodiment
03 As FIG. 1 shows, a lighting unit 10 in accordance with
04 one embodiment of the present invention comprises a lamp 12 and a
05 reflector 13 disposed in an opaque-sided housing 11 having a
06 removable protective transparent glass cover C. Unit 10 is
07 advantageously emplGyed in a variety of lighting systems to
08 provide high intensity, highly efficient, even illumination over
09 an area or work surface of particular size and shape and has a
preferred cut-off angle of about 35, to enable a person to work
11 or approach relatively close to -the lighting unit without seeing
12 the lamp or lamp reflection.
13 In one lighting system disclosed in FIG. 2, lighting
14 unit 10 is mounted on a support 16 so as to project light
upwardly in a cone CO along an optical axis Y for downward
16 reflection from a ceiling 19 onto a work area or work surface
17 therebelow, such as a floor 18, and the reflector opening 14 is
18 at or near the eye level plane EL of a standing person. The lamp
19 12, which provides relatively high lumens per watt of electrical
energy, such as a mercury metal halide or a high-pressure sodium
21 lamp, includes an elongated glass envelope 12B of circular cross
22 section surrounding a light source 12A therewithin. Lamp 12,
23 which is supported in a socket 15, is energizable from an
24 electric power source PS through a line cord L, a ballast 21,
and wire cable W in a conventional manner.
26 As FIGS. 3, 4, 5, and 6 show, the reflector 13, which
27 is fabricated of one or more pieces of specular reElective
28 material, such as polished anodized aluminum or metal-coated
29 Mylar (trademark~, comprises eight interrelated curved reflector
segments, namely: two side segments 30 and 30A on opposite sides
31 of lamp 12 and joined together along a line 30B behind the
32 _ 9 _
Zl~
01 lamp to reflect light emit-ted from the rear of the lamp; two end
02 segments 31 and 31A at opposite ends of the lamp, and four corner
03 segments 32, 32A, 32B, and 32C, each located between a side
04 reflector and an end reflector. The reflector 13 and lamp 12
05 cooperate to project a cone of light CO from the reflector
06 opening 14 onto ceiling 19 in a generally circular pattern of
07 even intensity and high efficiency at a cut-off angle A of 35
08 between plane EL in which the reflector opening 14 lies and the
09 side of cone CO, in a highly efficient manner. The lighting unit
10 can also be used to project light downwardly or horizontally,
ll if desired.
12 The lamp reflector 13 comprises two reflector segments,
13 such as side segments 30 and 30A located on opposite sides of the
14 lamp axis X, each having a first edge 41 and second edge 42
~15 spaced therefrom and a curved reflector surface 45 between those
16 edges. The first (outer) edges 41 of the two side reflector
17 segments 30 and 30A are spaced apart from each other and are
18 located in a front plane 46 on one (front) side of the lamp 12,
19 which is the plane in which the reflector opening 14 lies. The
second inner edges 42 of the two side reflector segments 30 and
21 30A are adjacent each other and are located in another rear plane
22 47 behind or at the r ar of the lamp 12 and are spaced from the
23 lamp. Each point on a curve Cl, shown in FIG. 4, defined by a
24 plane extending transverse to the lamp axis X and in-tersecting
the curved re~lector surface 45 of a reflector segment 30 or 30A,
26 is spaced far-ther away from the lamp 12 than the second inner
27 edge 42 of that reflector segment. Some points on this curve Cl
28 are located on the side of the other (rear) plane 47 which is
29 remote from the lamp 12. The curved reflector surfaces 45 of the
two side segments 30 and 30A are of the same length and size and
31 are symmetrical but reversely disposed.
32 -10 -
, . ..
''
~3Z~l~
01 Each of the end segments 31 and 31~ and each of the
02 corner segments 32, 32A, 32B, and 32C also has a first (outer)
03 edge 41 and a second (inner) edge 42 spaced therefrom. The end
04 segments and corner segments have curved reflector surfaces 48
05 and 49, respectively. Each outer edge 41 lies in the
06 aforementioned ~ront plane 46. The inner edges 42 of the end
07 segments 31 and 31A and the corner segments 32, 32A, 32B, and 32C
08 extend behind the lamp, as FIGS. 4, 5 and 6 show. The end
09 segments 31 and 31A are identical in size and configuration to
each other, except for a lamp socket hole 49 in end segment 31A,
11 but are reversely disposed. Similarly, the corner segments are
12 similar to each other. Each point on a curve C2 defined by a
13 plane which is transverse to the lamp axis X and intersects the
14 curved reflector surface 48 of an end segment 31, 31A, is spaced
farther from the lamp 12 than the inner edge of the end segment,
16 as FIG. 5 shows.
17 Each point on a curve C3 defined by a plane which is
18 transverse to the lamp axis X and intersects the curved reflector
19 surface 50 of a corner segment 32, 32A, 32B, 32C, is spaced
father from the lamp 12 than the inner edge of the corner
21 segment, as FIG. 6 shows.
22 With lighting unit 10 mounted as shown in FIG. 2, so as
23 to project light upwardly for reflection from ceiling 19 and
24 located ao that the reflector opening 14 is substantially a-t the
eye level EL of a standing person, a person can approach
26 relatively close to the lighting unit without being subjected to
27 a direct view of the high intensity lamp 12 or its reflection in
28 reflector 13, thereby eliminating the need for light directing
29 louvers or baffles which impair illuminatin efficiency.
As FIGS. 4, 5 and 6 make clear, radiation lines
31 directly from lamp 12 exit directly through opening 14 of
32 reflector 13. Radiation lines
33 - 11 -
~Z~l~
emitted from lamp 12 onto reflector 13 also exi~ from opening 14, 2adiation
lines emanating from the rear of lamp 12 are reflected once and in some
cases at least twice from reflector 13 before being emitted through opening 14,
thereby increasing lighting efficiency. However, no radiation line emitted
from opening 14 is less than 35~ above plane EL in FIG. 2.
FIG. 7 shows a graph based on actual tests and depicting the light
distribution pattern and candle power at various pdnts relative to a lighting
unit 10 of the size and type shown in FIGS. I through 6 and employing a 120
volt, 250 watt deluxe coated mercury lamp rated at 12, 300 lumens, such
lamp having an envelope 12B about 6-1/4 inches long and about 3-1/2 inches
in diameter. In the graph, the lines 60A, 61~, and 62A represent measure-
ments made at distances along the horizontal axes X, 61, and 62, respecitvely,
shown in top plan view in FIG. 3. The axes 61 and 62 are at 45 and 90~,
respectively, to lamp axis X. In the graph, the 0~ line lies along the optical
axis Y and the 90 line lies in front plane 46. The units 500 through 4500
represent candelas. The graph shows that light distribution from lighting
unit 10 is substantially even at all significant distances therefrom within the
desired cone CO.
The chart No. I shown below is a tested candle power summary on
20 which the graph in FIG. 7 is based.
~ he chart No. 2 shown below shows the tested zonal lumens and lamp
and fixture efficiency percentages of light unit 10 and indicates that it provides
an efficiency of 73, 32% of lumens emanating from lamp 12 in conjunction wi~h
reflector 13.
- 12 -
~Zll~
Ch,,rt No. I
CANDLEPO~ER SUMMARY OUTPUT
LU~l~NS
ANGLE ACROSS 67.5 45 22.5 ALONG
` 0 4320 4320 4320 4320 4320
4312 4347 4342 4366 4379 415
4386 4407 4331 4371 4424
4527 4504 4435 4439 4531 1257
4562 4476 4338 4292 4453
4327 4385 4332l~103 4199 1951
4138 4055 4043 3559 3881
4064 ~148 3736 3622 4153 2291
- 40 3816 2265 3251 1887 4264
3144 3431 2422 3269 3920 2184
2075 2413 1325 2334 2528
654 1158 449 1035 997 878
` 60 57 93 67 99 122
31 30 24 33 3 38
7 7 5 8 6
4 4 3 4 3 4
` 80 1 1 1 2
0 0 0 0 0 0
` 90 0 0 0 0 0
~`
':
:
Chart No. 2
ZONAL LUMENS AND PERCENTAGES
ZONE .LUMENS ~ LAMP p FIXTURE
o_30 3623 29.46 40.18
0-40 5g 13 48.08 65.58
0-60 8g75 72.97 99.53
0-90 9017 73.32 100.00
40-gO 3104 25.24 34.42
60-go 42 0.34 0- 47
90~ 180 0 0.00 0.00 1
o-180 9017 73.32 100.00
* * EFFICIENCY = 73.32p *
-13 -
01 Second Embodiment
02 As FIG. 8 shows, a lighting unit 110 in accordance with
03 a second embodiment of the present invention comprises a lamp 112
04 and a reflector 113 disposed in an opaque-sided housing 111.
05 Unit 110 is advantageously employed in a variety of lighting
06 systems to provide high intensity, highly efficient, even
07 illumination over an area or work surface of particular size and
08 shape and has preferred cut-off angles of about 25 and 70 at its
09 longitudinal edges, to enable a person to work or approach
relatively close to the lighting unit without seeing the lamp or
11 lamp reflection.
12 In a second lighting system disclosed in FIG. 9, two
13 lighting units llO are mounted on the underside of a support 116,
14 such as a cabinet or shelf, so as to project light downardly in
two cones C01 and C02 onto a work area or work surface about 18
16 inches therebelow, such as a desk top 118, and the reflector
17 opening 114 is at or near the eye level plane EL of a seated
18 person. Preferably, the units 110 are located at the sides of
l9 the desk top 118, as FIGS. 9 and lO show, so that they are not
directly in front of the desk user. The lamp 112, such as a
21 fluorescent tube, includes an elongated glass envelope 112B of
22 circular cross section surrounding a light source therewithin.
23 Larnp 112, which is supported in socket 115, is energi7able from
24 an electrical power source PS through a line cord L, a
transformer and ballast 121, and a wire cable W in a conventional
26 manner.
27 As FIGS. 8, ll and 12 show, the reflector 113, which is
28 fabricated of one or more pieces of specular reflective material,
2g such as polished anodized aluminum or metal-coated Mylar
(trademark), comprises two interrelated curved reflector segments,
31 namely: two side segments 130 and 130A on opposite sides of lamp
32 112 and joined toge-ther along a line 130B behind the
33 - 14 -
01 lamp 112 to reflect light emitted from the rear of the lamp. The
02 reflector 113 and lamp 112 cooperate to project a cone of light CO
03 from the reflector opening 114 onto desk top 118 in a generally
04 rec-tangular pattern of even intensity and high efficiency at a
05 cut-off angle A of about 25 between plane EL in which the
06 reflector opening 114 lies and one side of cone CO, and at a
07 cut-off angle B of about 70 between plane EL and the other side
08 of the cone, in a highly efficient manner. The light unit 110 can
09 also be used to project light upwardly or horizontally, if
desired.
11 The lamp relfector 113 comprises two reflector segments,
12 such as side segments 130 and 130A located on opposite sides of
13 the lamp axis Xl, each having a first edge 141 and second edge 142
14 spaced therefrom and a curved reflector surface 145 between those
edges. The first (outer) edges 141 of the two side reflector
16 segments 130 and 130A are spaced apart from each other and are
17 located in a front plane 146 on one (front) side of the lamp 112,
18 which is the plane in which the reflector opening 114 lies. The
19 second inner edges 142 of the two side reflector segments 130 and
130A are adjacent each other and are located in another rear plane
21 147 behind or at the rear of the lamp 112 and are spaced from the
22 lamp. Each point on a curve Cll, shown in FIG. 12, defined by a
23 plane extending transverse to the lamp axis Xl and intersecting
24 the curved reflector surface 145 of a reflector segment 130 or
130A, is spaced farther away from the lamp 112 than the second
26 inner edge 142 of that reflector segment. Some points on this
27 curve Cll are located on the side of the other (rear) plane 147
28 which is remote from the lamp 112. The curved reflector surfaces
29 145 of the two side segments 130 and 130A are of different lengths
and size, are not symmetrical, and are reversely disposed
31 relative to each other.
32 - 15 -
2~5
01 ~ith the lighting units 110 moun-ted as shown in FIGS. 9
02 and 10, so as to project light downwardly onto surface 118 and
03 located so that the reflector openings 114 are substantially at
04 the eye level EL of a seated person, a person can approach
05 relatively close to -the lighting units without being subjected to
06 a direct view of the lamps 112 or their reflection in reflectors
07 113, thereby eliminating the need for light directing louvers or
08 baffles which impair illumination efficiency.
09 As FIGo 12 makes clear, radiation lines directly from
lamp 112 exit directly ~hrough opening 114 of reflector 113.
11 Radiation lines emitted from lamp 112 onto reflector 113 also exit
12 from opening 114. Radiation lines emanating from the rear of lamp
13 112 are reflected once and in some cases at least twice from
14 reflector 113 before being emitted through opening 114, thereby
increasing lighting efficiency. However, no radiation line
16 emitted from opening 114 is less than about 25 below plane EL in
17 FIG. 9.
18 FIG~ 13 shows a graph based on actual tests and
19 depicting the light distribution pattern and candle power at
various points relative to a lighting unit 110 of the size shown
21 in FIG. 12 and employing a 120 volt fluorescen-t tube lamp 112
22 rated at 400 lumens, such as a General Electric type F8T5CW
23 fluorescent tube about 10-1/4 inches by 5/8 inches in diameter.
24 In the graph, the lines 160A, 161A, and 162A represent
measurements made at distances along the horizontal axes Xl, 161,
26 and 162, respectively, shown in FIG. 11. The axes 161 and 162 are
27 at 45 and 90, respectively, to lamp axis Xl. The graph shows
28 that light distribution from lighting unit 110 is substantially
29 even at all significant distances therefrom within the desired
cone C0.
31 The chart No. 3 shown below is a tested candle power
32 summary of the beam side of unit 110 and on which a portion of the
33 graph in FIG. 13 is based,
34
~L13ZllS
01 The chart No. 4 shown below shows the tested zonal
02 lumens and lamp and fixture e~iciency percentages of both sides
0~ of light unit 110 and indicate~ that it provides an efficiency o~
04 64.91~ of lumens emanating from lamp 112 in conjunction with
05 reflector 113.
06 The chart No. 5 shown below is similar to chart No. 3
07 but is a summary of the candle power on the side of unit 110
08 opposite the beam side.
09 The chart No. 6 shown below depicts measured light
distribution patterns measured at the points designatea 1 through
11 35 in desk surface 118 shown in FIGS. 9 and 10 which ~las 30 inches
12 by 60 inches in size.
13 Chart No. 3
14CANDLEPOWER SUMMARY OUTPUT
. 15BEAM SIDE LUMENS
16 ANGLEACROSS67.5 45 22.5 ALONG
: 17 0 56 56 56 5656
18 5 63 62 64 5759 3
19 10 73 67 64 5756
84 76 69 5552 10
. 21 20 97 86 80 5~49
:22 25 149 106 85 5344 21
23 30 219 lg4 97 5034
24 35 191 184 151 5233 39
,~ 25 40 190 173 177 5022
`- 26 45 175 163 150 5020 45
27 50 163 14~ 137 6017
: 28 55 153 136 12g 8117 48
29 60 144 128 119 7316
115 109 108 6012 41
31 70 78 73 84 45 5
32 75 33 36 48 31 0 18
33 80 0 1 13 12 0
34 85 0 0 0 0 0
:35 90 0 0 0 2 0
36 Chart No. 4
37 BOTH SIDES
38ZONAL LUMENS AND PERCENTAGES
~ 39
.40 ZONE LUMENS ~ LAMP % FIXTURE
41 0-30 50 12.64 19.47
42 0-40 97 24.38 37.56
i43 0~60 197 49.45 76.19
~44 0-90 259 64.91 100.00
40-90 162 40.53 62.44
46 ~0-90 61 15.45 23.81
~47 90-180 0 0.00 0.00
~48 0-180 259 64.91 100.00
j 49* * EFFICIENCY = 64.91% * *
- 17 -
~1~211S
ChartNo. 5
,
OPPOSITE SIDE TO BEAM
CANDLEPOWER DATA
ANGLE PLANE OUTPUT
ACROSS67.5 4522.5 ALONGAVERAGE LUMENS
0 55 S5 55 55 55 55
48 50 52 53 56 ~2 2
42 ~6 ~9 50 55 48
38 42 40 46 52 43 6
39 42 37 41 49 41
38 44 36 35 45 39 9
31 40 28 23 37 31
29 36 32 24 33 31 B
14 17 18 11 21 16
9 14 15 21 13 5
0 ~ 9 16 22 10
0 0 5 16 19 8 3
0 2 0 14 19 6
0 0 0 8 13 4 2
0 1 0 2 9 2
0 2 0 0 3
0 2 0 0 0
0 0 0 0 0 0 0
,
-18-
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01 Third Embodiment
02 As FIG. 14 shows, a lighting unit 210 in accordance with
03 a third embodimen-t of the present invention comprises two lamps
04 212 and 212A, each similar to ~luorescent lamp 112 hereinbefore-
05 described, and a reflector 413 disposed in an opaque-sided housing
06 211. Unit 210 is advantageously employed in a variety of lighting
07 systems to provide high intensity, highly efficient, even
08 illumination over an area or work surface of particular size and
09 shape and has preferred cut-off angles shown in the graph in FIG.
16, to enable a person to work or approach relatively close to the
11 lighting unit without seeing the lamp or lamp re~lection.
12 One or more lighting units 210 can be mounted in the
13 same manner as unit 110 hereinbefore described so as to project
14 light downwardly in a cone CO onto a work area or work surface
therebelow, such as the desk top 118 shown in FIGS. 9 and 10, and
16 the reflector opening 214 is at or near the eye level plane EL of
17 a seated person.
18 As FIGS. 14 and 15 show, the reflector 413, which is
19 fabricated of one or more pieces of specular reflective material,
such as polished anodized aluminum or metal-coated Mylar
21 (trademarX), comprises four interrelated curved reflector
22 segments, namely: two side segments 230 and 230A on opposite sides
23 of lamp 212 and joined together along a line 230B behind the lamp
24 212 to reflect light emitted from -the rear of the lamp 212, and
two additional side segments 330 and 330A on opposi-te sides of
26 lamp 312 and joined together along a line 330B behind lamp 312 to
27 reflect light from the rear of lamp 312. The reflector 413 and
28 lamps 212 and 312 cooperate to project a cone of light CO from the
29 reflector opening 214 onto desk top 118 in a generally rec-tangular
pattern of even intensity and high efficiency at a
31 - 20 -
z~
01 preferred cut-off angle A of about 25 between plane EL in which
02 the reflector opening 214 lies and one side of cone CO (see FIG.
03 15), and at a cut-ofE angle B of about 75% between plane EL and
04 the other side of the cone in a highly efficient manner. The
05 lighting unit 210 can also be used to project light upwardly or
06 horizontally, if desired.
07 The two reflector side segmen-ts 230 and 230A are located
0~3 on opposite sides of the lamp axis X2, each having a first edge
09 241 and second edge 242 spaced therefrom and a curved reflector
surface 245 between those edges. The first outer edges 241 of the
11 two side reflector segments 230 and 230A are spaced apart from
12 each other and are located in a front plane 246 on one (front)
13 side of the lamp 212, which is the plane in which the reflector
14 opening 214 lies. The second inner edges 242 of the two side
reflector segments 230 and 230A are adjacen-t each other and are
16 located in another rear plane 147 behind or at the rear of the
17 lamp 212 and are spaced from the lamp 212. Each point on a curve
18 C21, shown in FIG. 15, defined by a plane extending transverse to
19 the lamp axis X and intersecting the curved reElector surface 245
of a reflector segment 230 and 230A, is spaced farther away from
21 the lamp 212 than the second inner edge 242 of that reflector
t 2~ segment. Some points on this curve C21 are lcoated on the side of
23 the other (rear) plane 247 which is remote from the lamp 212. The
24 curved reflector surfaces 245 of the two side segments 230 and
230A are of different lengths and size, are not symmetrical, and
26 are reversely disposed relative to each other.
27 The two reflector side segments 330 and 330A are located
28 on opposite sides of the lamp axis X3 each having a first edge 341
29 and a second edge 342 spaced therefrom and a curved reflector
surface 345 between -those edges. The first (outer) edges 341 of
31 the two side reflector segmen-ts 330 and 330A are spaced
32 - 21 -
l~Z~
01 apart from each other and are locate-1 in a fron-t plane 346 on one
02 (front) side of the lamp 312, which is the plane in which the
03 reflector opening 314 lies. The second inner edges 3a2 of the two
04 side reflector segments 330 and 330A are adjacent each other and
05 are located in another rear plane 347 behind or at the rear of the
06 lamp 312 and are spaced from the lamp 312. Each point on a curve
07 C31, shown in FIG. 15, defined by a plane extending transvarse to
08 the lamp axis X3 and intersecting the curved reflector surface 345
09 o~ a reflector segment 330 or 330A, i8 spaced farther away fro~n
the lamp 312 than the second inner edge 342 of that reflector
11 segment. ~ome points on this curve C31 are located on the side of
12 the other (rear) plane 347 which is remote from the lamp 312. The
13 curved reflector surfaces 345 of the two side segments 330 and
14 330A are of different lengths and size, are not symmetrical, and
are reversely dispoaed relative to each other.
16 With lighting units 210 mounted like units 110, as shown
17 in FIGS. 9 and 10, so as to project light downwardly onto surface
18 118 and located so that the reflector openings 214 are
19 substantially at the eye level EL of a standing person, a person
can approach relatively close to the lighting unit without being
21 subjected to a direct view of the lamps or -their reflection in
22 reflector 413, thereby elimina-ting the need for light directing
23 louvers or baffles which impair illumination efficiency.
24 FIG. 16 shows a graph based on actual tests depicting
candle power at various points relative to a lighting unit 210 of
26 the size shown in FIG. 15 and employing two fluorescent tubes of
27 the type described. In the graph, the lines 260A, 261A, and 262A
28 represent measurements made at distances along the lamp axes X2,
29 X3 and 261, and 262, respectively, shown in FIG. 14.
- 22 -
The aAYes 261 and 262 are at 45 and 90G, respecti~ely, to axes X~, ~3,
The graph shows that light distribution from light:ing unit 210 is subs.antially
even at all significant distances therefrom within the desired cone,
The chart No, 7 shown below is a candle power summary on which
the graph in FIG. 16 is based.
The chart No. 8 shown below shows the tested zonal lumens and lamp
and fix+ure efficiency percentages of light unit 210 and indicates that it
provides an efficiency of 77. 48% of lumens emana~in~ from the lamps 212 and
312 in conjunction with reflector 413,
Chart No. 7
CANDLEPOWER SUMMARY OUTPUT
. ' B~AM SIDE LUMENS
A~GLE ACROSS 67.5 45 22.5 ALONG
O 152 1~2 1~;2 152 . 152
171 170 166157 149 B .
185 182 176163 146
1~. 194 189 18116~ 142 25
203 196 . 183162 135
225 213 1~7 160129 43
~0 252 239 199 15~ 122
254 ` 245 206- 148 ~10 62
266 257 .224150 101
26~- 25~ 214 141 88 76
263 . 249 203 134 76- .
26~0 247201 129 66 83
6~ 256 244196 120 . 54
235 225189 1~9 43 80
7~ 195 189162 95 29
75 151 148134 85 17 59
: 80 119 112- 91 65 . 7
~5 90 8~65 37 1: 32.
62 .5642 22 0
Chart No. 8
BOT~ SIDES .'-
- ZONAL LUMENS AND PE~CENTAGES
.~ , ~ .
ZONELUMENS % LAMP FIXTURE
0-30 120 15.07 .19.45 !
0-40 20g 26. 22 33.84
-- 0-60 420 52.62 . 67.92
0-9~ 619 77.4~ 100.00
,40-90 410 51.26 66.16
60-90 19~ 24.86 32.08
90-180 0 0.00 0.00
0-180 619 77.48 100.00
** EFFICIENCY = i7.48% **
- ~3-
