Petitioner: Haag-Streit AG
`Petitioner: Haag-Streit AG
`
`Ex. 10(cid:20)(cid:26)
`
`EX. 1017
`
`

`

`United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,301,090
`
`Bed
`
`[45] Date of Patent:
`
`Apr. 5, 1994
`
`U5005301090A
`
`4,885,663 12/1939 Parker ................................... 362/32
`
`4,907,132 3/1990 Parker .......
`362/32
`
`4,933,313 6/1990 Berger ............ 362/2
`7/1991 Bomhorst ............................. 362/32
`5,031,073
`
`Primary Examiner—Richard R. Cole
`Attomey, Agent, or Finn—Herbert Dubno
`[57]
`ABSTRACT
`A luminaifc which has in its housing a multiplicity 0f
`groups of light emitters of different colors or pluralities
`of optical waveguides constructed to emit light progres-
`sively along the lengths thereof and a diffuser at which
`the colors can be mixed and from which the light
`emerges. The emitters can be controlled at the housing
`or light can be delivered to the optical waveguides by
`optical fibers from remote light sources.
`
`16 Claims, 8 Drawing Sheets
`
`
`
`[54] LUMINAIRE
`
`[75]
`
`,
`Inventor: Aharon Z. Bed, 12 Wagon Trail,
`Nashua, NH. 03062
`
`[73] Assignee: Aharon Z. H911, Nashua, NH
`[21] App]. No.: 851,620
`[22] Filed:
`Mar. 16, 1992
`[51]
`Int. Cl; ................................................ F21V 8/00
`[52]
`11.5. c1. ...................................... 362/32; 362/101;
`362/320; 352/373
`[58] Field of Search ................... 362/1, 2, 32, 231, 96,
`362/320, 101, 294, 373
`.
`References Cited
`U-S- PATENT DOCUMENTS
`3,517,180 6/1970 Semotan .................................. 362/1
`3,902,056
`8/1975 Aizenberg et a1.
`..................... 362/1
`
`[56]
`
`1
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`40
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`I
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`J
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`@flfl
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`@(6)
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`42' 43
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`46' 47' 48
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`41'
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`49
`
`OPTICAL INTERFACES
`
`GREEN
`SOURCE
`
`RED
`SOURCE
`
`CONTRQLLER7
`
`BLUE SOURCE
`
`
`

`

`US. Patent
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`‘ Apr.5, 1994
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`Sheet 1 of 8
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`5,301,090
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`

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`US. Patent
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`Apr. 5, 1994
`
`Sheet 2 of 8
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`5,301,090
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`
` 23
`
`CONTROLLER
`
`0 0 0
`
`
`
`FIG.2A
`
`FIGZB
`
`

`

`US. Patent
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`Apr. 5, 1994
`
`Sheet 3 of 8
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`5,301,090
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`‘\\\ 1:
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` r——
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`F|G.3
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`

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`US. Patent
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`Apr. 5, 1994
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`Sheet 4 of 8
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`5,301,090
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`8‘“ \w
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`6 3
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`

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`US. Patent
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`Apr. 5, 1994
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`Sheet 5 of 8
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`5,301,090
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`OPTICAL INTERFACES
`
`GREEN
`SOURCE
`
`RED
`SOURCE
`
`CONTROLLER7
`
`BLUE SOURCE
`
`
`

`

`US. Patent
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`Apr. 5, 1994
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`Sheet 6 of 8
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`5,301,090
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`FIG.6
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`

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`US. Patent
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`Apr. 5, 1994
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`Sheet 7 of 8
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`5,301,090
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`LIGHT SOURCES
`
`OPTICAL INTERFACES
`
`102
`
`104
`
`101
`7/III/IIIIII/III/I/I/I/II/I.’
`
`
`CIRCADI AN
`CYCLE
`CONTROLLER
`
`105
`
`FIG]
`
`

`

`US. Patent
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`Apr. 5, 1994
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`Sheet 8 of 8
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`5,301,090
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`

`

`1
`
`LUMINAIRE
`
`5,301,090
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`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application relates to my copending applications
`Ser. No. 07/788,184 filed on Nov. 5, 1991, entitled
`“Light Weight Low Loss Refractive Light Diffusion
`System” and Ser. No. 07/813,972 filed Nov. 26, 1991
`entitled “Controlled Light Extraction From Light
`Guides and Fibers” now US. Pat. No. 5,222,795 issued
`Jun. 29, 1993.
`FIELD OF THE INVENTION
`
`The present invention relates to a lighting device or
`apparatus, hereinafter referred to generally as a lumi-
`naire, for general or specified lighting of an area or
`space and, more particularly, to a family of highly ho-
`mogeneous controlled color light sources as well as
`controlled color luminaires. The invention relates to a
`luminaire which can be powered remotely, i.e. can emit
`in a homogeneous fashion light which is transmitted to
`it from a distance, to a luminaire which is flexible and
`foldable so as to be deployable under field conditions,
`and to a luminaire intended for environmental modifica-
`tion, therapy and/or decorative lighting purposes.
`BACKGROUND OF THE INVENTION
`
`light sources are available in
`In general, artificial
`either a predetermined broad spectrum or in an almost
`monochromatic form. Some well known “white” light
`sources include incandescent lamps, high intensity dis-
`charge (HID)
`light sources and fluorescent
`light
`sources. Among the better known monochromatic light
`sources we can cite light emitting diodes, lasers of all
`types and gas discharge tubes. What has not been freely
`available heretofore, is an efficient light source with a
`temporally variable spectral output, or at least a time-
`variable appearance. Currently, when the need for such
`means of illumination arises, one can either use filters to
`allow only part of the spectrum of a white light source
`to be seen, or, one can use discrete light sources of
`different spectral distribution to illuminate a single
`scene. Both of these approaches are cumbersome.
`For instance, when using filters, the segment of the
`spectrum filtered out is lost to absorption and thus there
`is a major reduction in the system efficiency. It is desir-
`able to have flat light sources with variable chromatic-
`ity and a large degree of luminance homogeneity,
`which can be modular so as to allow for stepwise in-
`crease in total light output from single powering source.
`In most current lighting systems, the conversion of
`electrical power to light flux occurs at the point of use
`of the light. Since the efficiency of conversion of elec-
`tricity to visible light is rarely more than 25%, and in
`some very large light sources, 30%, a large amount of
`heat must be dissipated at the point of use of the light.
`Furthermore, there are special situations, particularly in
`hazardous environments, where it is not desirable to
`have electrical connectors, conductors or any electri-
`cally powered devices within the space that is to be
`illuminated. In such areas the light sources and their
`associated wiring must be enclosed in special enclo-
`sures, a fact that increases installation costs and reduces
`efficiency of light output utility. It is thus desirable to
`provide luminaires which are remotely powered so as to
`allow for heat withdrawal at the remote location where
`electricity is converted to light, allow safe installation in
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`hazardous environment, and provide for controllable
`chromaticity.
`Light sources of the latter type can be used in a broad
`variety of environments including photographic dark
`rooms, semiconductor and other clean room manufac-
`turing environments as well as in chemical plants where
`explosive or flammable products are being manufac-
`tured.
`
`OBJECTS OF THE INVENTION
`
`The principal object of the invention is to provide an
`improved lighting apparatus which is free from the
`drawbacks described, has one or more of the advan-
`tages outlined and which is efficient and reliable.
`It is another object of the instant invention to provide
`light sources whose chromatic appearance can be mod-
`ulated.
`It is yet another object of the instant invention to
`provide such light sources in a modular form. It is yet
`another object of the instant invention to provide lumi-
`naires where the energy conversion processes from the
`power source to luminous flux occurs at a site distant
`from the point of use of the light.
`It is yet another object of the instant invention to
`provide for such luminaires that are portable and easily
`foldable, inflatable and deployable. It is yet another
`object of the instant invention to provide luminaires
`that are washable and can be immersed in water without
`the danger of shorting live electrical wires or contacts
`since dust accumulation on light sources can severely
`degrade their performance due to light absorption by
`the dust.
`It is also an object of the invention to provide a lumi-
`naire particularly suitable for the modification and re-
`setting of human circadian cycle, as taught by C. A.
`Czeisler in US. patent application Ser. No. 07/066,677,
`where very high intensity light sources capable of deliv-
`ering at least 7500 lux are required, and, when desired,
`without having to discharge the heat generated from
`such light sources within the space where the light is
`used.
`
`SUMMARY OF THE INVENTION
`
`These objects and others which will become apparent
`hereinafter are attained, in accordance with the instant
`invention by a unique system for mixing colored light.
`In a first aspect of the invention, an array of comple-
`mentary colored light sources (red, green and blue) is
`embedded within luminaire whose chromaticity is con-
`trolled by controlling the output of the three groups of
`light sources. The light from these sources can be inter-
`mixed with the help of the specially designed light dif-
`fuser disclosed in copending application Ser. No.
`07/788,184.
`In a second aspect of the invention, light is transmit-
`ted from remotely positioned complementary light
`sources to a luminaire which contains light extraction
`elements as described in copending application Ser. No.
`O7/813,972(U.S. Pat. No. 5,222,795), the light from the
`three colored light sources is then intermixed and irradi-
`ated through the surface of the luminaire with the help
`of similar diffusers. In both cases chromatic control of
`the appearance of the luminaire is obtained.
`The light extractor based luminaire can be used for
`dual color applications, like the control and shifting of
`human circadian cycle, clean rooms in semiconductor
`foundries and photographic dark rooms.
`
`

`

`3
`The principles of the instant invention are applicable
`to the illumination of industrial, petrochemical and
`other hazardous environment, that use the unique fea—
`ture of the instant invention that provides for the re-
`mote location of light sources from the point of use of
`the light and the unique homogeneous distribution of
`light obtained from the luminaires of the instant inven-
`tion, are described as well. Similarly, the immunity of
`the luminaires to immersion in water, derived from the
`same feature of remote location of the light source,
`serves as a basis for illuminating devices that can be
`used in conjunction with wet environment like bathing
`units, steam baths, swimming pools and other unique
`applications.
`the luminaire according to the
`More particularly,
`invention can comprise:
`a housing;
`a light-transmissive diffuser extending across the
`housing for diffusing light impinging upon the diffuser
`from within the housing;
`a multiplicity of groups of light emitters in the hous-
`ing, each group consisting of three emitters emitting
`light of complementary colors, the groups being spaced
`apart over an area of the diffuser, whereby the light
`from the emitters in a group mixes at and is diffused by
`the diffuser; and
`means for energizing the light emitters.
`In general, where I use the term “monochromatic” to
`describe the light emitted by one of the light sources of
`a group, it should be noted that the term is intended to
`be used in a loose sense to indicate that the sources have
`different output colors and that the colors are selected
`so that the combination of light colors emitted by the
`group has the desired composite effect, e.g. white light.
`The “monochromatic” light of each emitter can have a
`wider or narrower band width as desired.
`
`Alternatively, the luminaire can comprise:
`a light-transmissive diffuser extending across the
`housing for diffusing light impinging upon the diffuser
`from within the housing;
`a multiplicity of elongated light guides in the housing
`emitting light over respective lengths thereof; and
`means at an end of the housing for injecting light into
`corresponding ends of the light guides.
`The diffuser is preferably of the type described in the
`aforementioned
`copending
`application
`Ser. No.
`07/788,184 which is hereby incorporated in its entirety
`by reference and comprises two spaced-apart diffuser
`layers and, where the light-emitting members are opti-
`cal waveguides or fibers, that may be constructed and
`configured as described in my copending application
`Ser. No. 07/813,972 (US. Pat. No. 5,222,795), also in-
`corporated in its entirety by reference herein, the opti-
`cal waveguides or fibers having a cladding removed
`over the length of the optical waveguide or of varying
`refractive index to provide for the controlled light emis-
`sion along the length thereof.
`The diffuser can form a wall of a space to be illumi-
`nated, for example, the wall of a room, of a bathing
`facility or of a treatment facility for modifying the cir-
`cadian rhythm, or a wall of a bathing device such as a
`shower or bath enclosure, swimming pool or the like.
`The means for energizing can include control means
`at the housing for controlling the outputs of the light
`emitters of different color and thereby controlling the
`color balance and intensity of the luminaire, or means
`remote from the housing and connected to the housing
`by electrical conductors where the light sources are
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`4
`emitters in the housing or by optical waveguides or
`light-conducting fibers where the light source is, or
`light sources are, remote from the housing.
`The control means can include means for selectively
`energizing the light emitters of one group differently
`from the light emitters of another of these groups to
`provide a surface whose appearance can be modified
`zonally.
`The luminaire may be one of a plurality of panels
`assembled together by plug and socket means and
`where light conductors are used to distribute the light
`from a common source,
`the conductors may be
`branched to the different panels.
`The housing, diffuser and array of light emitters or
`optical waveguides may be flexible to allow bending.
`and/or inflation and deflation of the luminaire and, as
`noted, the luminaire may have sufficiently high inten-
`sity and control means to provide for light induced
`circadian cycle modification and shifting.
`BRIEF DESCRIPTION OF THE DRAWING
`
`The above objects, features and advantages of the
`instant invention will become more readily apparent
`from the following description, reference being made to
`the accompanying drawing in which:
`FIG. 1 is a perspective view, partly cut away, of an
`LED-based chromatic luminaire according to the in-
`vention;
`FIG. 1A is detail view of the region IA of FIG. 1;
`FIG. 2 of a system of modular LED-based luminaire;
`FIG. 2A is a diagram to a larger scale of a plug mem-
`ber at one end of such a modular luminaire;
`FIG. 23 is a diagram of the female or socket member
`thereof;
`FIG. 3 is a schematic view similar to FIG. 1 of a
`chromatic luminaire based on light extractor fibers;
`FIGS. 4A and 4B are diagrammatic cross sectional
`views of extractor-based chromatic luminaires;
`FIG. 4C a cross section through a light extractor used
`in such a luminaire;
`FIG. 5 is a diagram, partly in section, of a chromatic
`luminaire system based on light extractor fibers;
`FIG. 6 is a similar view of an extractor-based white
`light luminaire where the light source and the luminaire
`are remotely positioned relative to each other;
`FIG. 7 is a view similar to FIG. 5 of a human circa-
`dian adjusting system using light-extractor-based lumi-
`naire of the instant invention; and
`FIGS. 8A and SB are respectively a top and rear
`cross sectional view of an illuminated bathing unit using
`light-extractor-based luminaires of the instant invention.
`SPECIFIC DESCRIPTION
`
`FIGS. 1 and 1A show a luminaire 1 which consists of
`a box-like structure having essentially three parallel
`sheets or planes, 2, 3 and 4. The inner surface of the
`bottom sheet 2,
`is a highly reflective material or is
`coated with a highly reflective material. This coating
`can be either a specular or a diffuse reflector. In the
`former case, aluminized Mylar can be used; in the latter
`case, one can use 3M’s V-5115 Scotch'rM Light Ex-
`tractor Film, or a highly reflective paint like Spraylat
`Corporation’s Lacryl Series 20-02 matte white paint.
`An array of groups 5 of light sources 6, 7, 8 are fas-
`tened on the bottom sheet 2, and include respectively a
`red light source, a green light source and a blue light
`source. The light sources are mounted in such a way
`that the light is emitted to the inner space of the box and
`
`

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`5,301,090
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`5
`toward the middle plane 3. The middle sheet 3 and the
`top sheet 4 are light diffusing screens as described in my
`copending application Ser. No. 07/788,184 entitled
`“Light Weight Low Loss Refractive Light Diffusion
`System”. In essence, the two sheets and 4 form one
`diffusing screen.
`The three main sheets of the luminaire are assembled
`into the box shown in FIG. 1, with side panels like the
`panels 9 and 10 and a front element 11 which houses the
`electrical connections and control system for the lumi-
`naire. The power line 18 depicted in FIG. 1, can be
`replaced with a more complex set of conductors which
`can carry control signals to the luminaire in order to
`change its chromatic appearance as more fully de-
`scribed below.
`FIG. 1A shows the details of one group 5, of the
`tricolor light sources. As can be seen, each light source
`is fed by two parallel conductors. These are the conduc-
`tors 12 and 13 for the red light source 6, conductors 14
`and 15 for the green light source 7 and conductors 16
`and 17 for the blue light source 8.
`Therefore, all the light sources of a given color (red,
`green or blue) within a given row of the array are pow-
`ered in parallel by the same pair of conductors. By
`assuring that the same pair of wires powers the same
`color light sources in all the rows of a given luminaire
`(which can easily be done by correctly connecting the
`extremities of the conductor pairs, either in parallel or
`in series), I can control the amount of light emitted by
`each set of light sources according to their color.
`While in FIGS. 1 and 1A the light emitting diodes are
`shown to be relatively widely spaced apart, it should be
`understood that in practice the light emitting diodes
`within a group are spaced as close together as is practi-
`cal.
`
`The use of the dual screen diffuser composed of the
`sheets 4 and 3, assures that light emitted from the indi-
`vidual light sources emanates from the outer surface of
`the luminaire completely intermixed. This can be
`achieved by having the periodicity of the screens be a
`whole multiple (including the same period) of the per-
`iod of the light sources groups. Another means to
`achieve the same goal is to place the three light sources
`in each group adjacent to each other, so light from them
`cannot be optically resolved. The latter implementation
`is particularly useful when using solid stat light sources
`in the form of very small light emitting diodes as de-
`scribed below.
`
`It has been known for quite some time that one can
`duplicate the appearance to the human eye of any color
`by the appropriate admixture of light from three pri-
`mary colored and monochromatic light sources. The
`choice of the three primary colors is not necessarily
`unique, and many different sets of color matching func-
`tions are possible. One standard was adopted in 1931 by
`the International Commission on Illumination (C113),
`and this standard is the basis of modern chromatic
`scales. This standard uses basically the summation of
`light sources with the primary colors red, green and
`blue (or the RGB system), to match any desired color
`perception.
`The subject is discussed in “Principles of Color Tech-
`nology” by Billrneyer, F.W. and Salzman M., 2nd edi-
`tion, 1981, published John Wiley & Sons, or in “Light,
`Color and Vision” by LeGrand Y. 2nd edition, 1957,
`published by Wiley (Interscience). Therefore, by con-
`trolling the intensity of the light emitted by the three
`types of light sources within the groups that form the
`
`6
`array in the luminaire described in FIG. 1, I can control
`the chromaticity or color appearance of the luminaire.
`This is achieved either with the control knobs 19, which
`in essence are rheostats controlling the power to all the
`green, the red and the blue light sources respectively, or
`through an appropriate control line consolidated in the
`power line 18.
`In the preferred embodiment of the luminaire shown
`in FIG. 1, the light sources are simply small light emit-
`ting diodes, or LED’s. These are available in a large
`variety of shapes and flux outputs from 'a number of
`manufacturers. For instance Hewlett Packard of Cali-
`fornia provides a full line of LED’s ranging in size from
`miniature devices to large devices having luminosity in
`the rang of microcandela to one candela. Hewlett Pack-
`ard supplies both red (wavelength typically around 630
`nanometers) and green (wavelength typically 560 nano—
`meter) light emitting diodes suitable for the instant in-
`vention.
`These commercial LEDs are usually encapsulated to
`facilitate mounting and shipment. In the instant inven-
`tion one can use such commercial LEDs as well as
`purchase LEDs dies (not encapsulated, and thus lower
`the overall cost of system) and solder the dies to the
`their respective conductors directly.
`Until recently, blue LEDs were not available, this
`due to the need for relatively large band gap semicon-
`ductors. In the last two years, however, advances in
`silicon-carbide based semiconductors have made blue
`LEDs available, and at least one company, Cree Re-
`search (Durham, N.C.) is providing blue LEDs on a
`commercial basis. One of the advantages in using LEDs
`as the light sources in the instant invention is the fact
`that the output of the LED scales with the voltage
`applied over a relatively large range. As a result, one
`can control the light output and the chromaticity of a
`luminaire over a relatively large range.
`In the prior art, one usually uses a traditional white
`light source and controls the color by filtering out the
`desired parts of the spectrum. This approach is wasteful
`of the energy resources available to power such light,
`since the absorbed segment of the spectrum is converted
`to heat in the absorbing medium.
`In the instant invention, I can create the desired color
`by adding primary colors at the desired ratio to yield th
`desired chromaticity, and need not absorb any part of
`the light emitted by the colored light sources. This
`approach has the additional advantage that one can
`easily modulate the light chromaticity in a continuous
`fashion by adjusting the power to the three different
`groups of primary color light sources. Such adjustments
`are extremely difficult to achieve in the prior art.
`FIG. 1 shows a specific arrangement of the LEDs,
`namely they are arranged in rows of RGB groups, with
`all the groups within a column having the same relative
`orientation and with adjacent columns having mirror
`inverted orientation. It should be understood that other
`symmetries will result
`in operative embodiments as
`well. For instance, the light emitting diodes can be
`arranged in columns of groups all having the same sym-
`metry. The order of the colors between adjacent col-
`umns need not be kept the same in all columns. The
`groups of light sources are shown in FIG. 1 to form
`rows of groups, but other arrangements will result in
`operative embodiments as well, for instance groups in
`adjacent columns can be displaced relative to each
`other.
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`7
`Light sources as shown in FIG. 1 can be easily
`‘adapted to provide for modular lighting. Namely, one
`can affix a frontal multi-prong male plug and a back
`plane mating female plug to these luminaires so that
`they can be inserted into each other to provide a light
`source of any practical length. Such an arrangement is
`shown in FIG. 2, where a top view of three luminaires
`20, 21 and 22 of the instant invention are depicted. Each
`of these luminaires is essentially a device as shown ear-
`lier in FIG. 1, which can be fastened to the others with
`the multi—pronged assemblies 28 and 29, shown in more
`details in FIGS. 2A and 2B respectively. These fasten-
`ing assemblies serve a dual role, first they allow for
`interconnecting adjacent luminaires, second they pro-
`vide for electrical connections to the light emitting
`diodes within the luminaires.
`In a preferred embodiment, the light sources are con-
`trolled from a single controller 23 which regulates the
`power to all red, all green and all blue light emitting
`diodes. To minimize the number of conductors, the
`multi-pronged fasteners, or plugs have four conductors,
`one conductor each, 24, 25 and 26 respectively, for the
`red, green and blue sets of light emitting diodes and one
`common ground conductor 27.
`FIG. 2B shows the female plug with its respective
`inserts 24a, 25a and 26a for the light emitting diode
`conductors and 27a for the common ground conductor.
`The plugs have a built-in asymmetry to assure correct
`interconnection between modules. In this fashion, the
`chromaticity of the total assembly is controlled from
`the single controller, through the control knobs 30, 31
`and 32 respectively.
`The assembly also includes a power feeding four-con-
`ductor cord 35 terminated with a plug 34 structured in
`the same fashion as the male plug 2 described in FIG.
`2A. This allows for interfacing the controller 23 to the
`first luminaire 20 by simple insertion of the male plug 34
`into the female plug 29 of the luminaire. When one
`assembles a series of luminaires by inserting each male
`plug in the female plug of the subsequent luminaire, one
`obtains a modular lighting system which can be sized
`according to the specific need. The last male plug in
`such a series would be exposed, and I thus provide for
`a contactless (insulating) cover, 33, having the same
`form as the female plug 29 described in FIG. 23, to
`terminate the light assembly.
`In some applications of the modular luminaires de-
`scribed in FIG. 2, one can use dedicated conductors to
`distribute power between different luminaires in a sys-
`tem while in some other applications, the conductors
`used to power the light emitting diodes are simply con-
`tinued to the next luminaire through the multi pronged
`connectors.
`'
`Since the light emitting diodes of a given color are
`connected in parallel, the failure of a limited number of
`LEDs would not negatively impact the operation of the
`entire assembly.
`It should be clear that these luminaires can be fas-
`tened to various surfaces by a variety of means, includ-
`ing the provision of a protruding perforated lug for
`screws or even an adhesive band on the back side of the
`luminaire.
`Control functions can, of course, be associated with
`each separate luminaire rather than being consolidated
`into a single control module. When such a design is
`desired, then each luminaire has its own independent
`circuit, and the prongs are used to transfer the main
`power from luminaire to luminaire and a unique set of
`
`10
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`15
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`20
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`5,301,090
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`8
`conductors is used for this purpose (namely, these con-
`ductor do not serve as direct power feeding lines to the
`individual light emitting diodes).
`One of the advantages of the luminaires shown in
`FIG. 2 is that they can be constructed of relatively
`flexible materials. The conductors can be thin strips of
`copper deposited on plastic or partially embedded in a
`plastic substrate, as practiced in flexible planar cables.
`Since the light emitting diodes are relatively small, the
`whole assembly can be flexed and bent so as to fit on
`curved surfaces. Such flexible luminaires are not gener-
`ally available in the prior art.
`While in the above description of the preferred em-
`bodiment I have referred to the light sources as light
`emitting diodes,
`it should be understood that other
`monochromatic light sources could be used, including
`monochromatic miniature gas discharge (“neon light")
`light sources, or even incandescent light sources with
`appropriately colored external envelopes. It should be
`understood, however,
`that the latter method is ex-
`tremely inefficient, in that only a very small percentage
`of the energy used to power the system results in visible
`light. The reason is that in the first place small incandes-
`cent light sources are very inefficient to start with, and
`second, a large proportion of their emitted light is ab-
`sorbed in the process of rendering them “monochro-
`matic”.
`Under some unique conditions, it might be desired to
`gradually change the chromatic appearance of the lumi-
`naire essentially on a zone by zone basis, so as to obtain,
`for instance, a surface whose chromatic appearance
`changes gradually from zone to zone. In this event, I
`can provide additional control lines to control the chro-
`maticity of specific zones individually. In practice, the
`light emitting elements would be arranged in an array of
`groups, or the luminaire would be divided into seg-
`ments with each array or segment having its own con-
`trol line that can be controlled independently, accord-
`ing to the application.
`For instance, one would provide for control of a
`column of groups of LEDs, but not for each group
`within the column. The utility of such devices would be
`mostly in advertising boards and displays, where one
`would draw a viewer’s attention to a display by provid-
`ing back illumination that varies in both space and time.
`There are a number of applications where it is not
`desired to have electrical wiring within the luminaire
`and/or where the light sources need to be concentrated
`at one part of the luminaire to facilitate heat rejection.
`When this is the case, an alternative embodiment of the
`instant invention is provided, as shown schematically in
`FIG. 3, for the luminaire 40. This luminaire 40 has a
`general structure which is similar to that described in
`FIG. 1, in that it consists of a box having three parallel
`sheets 41, 42 and 43 fastened together as a container.
`The base plane 41,
`is made of a highly reflective
`substance or is covered with a reflective substance.‘As
`above, this structure can be made of a variety of materi-
`als including flexible plastics. When inflexible sub-
`stances are chosen, the base 41 inner surface can be
`covered with a white paint or films as described above.
`One can also use for some applications a specularly
`reflective inner surface like an aluminized (or silvered)
`Mylar film. Similar treatments are provided for all other
`reflective surfaces, like the side walls 44. The sheets 42
`and 43 are two diffusion screens as described for the
`embodiment in FIG. 1 and are based on my copending
`application Ser. No. 07/788,184.
`
`

`

`5,301,090
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`9
`The box-like element 45, which can be termed the
`“light bar", contains complementary light sources, for
`instance monochromatic blue, red and green light emit-
`ting diodes or groups of such diodes. The light emitted
`from each such diode is concentrated by either refrac-
`tive or by reflective optics into individual light extrac-
`tion fibers, or light guides 46, 47 and 48. The optics is
`such that essentially all the light enters the extraction
`fibers within their respective angle of acceptance. The
`light extraction fibers are grouped in parallel and
`closely spaced groups, so that the light emanating from
`the extraction zone of each fiber is intermixed with light
`extracted from its neighboring fibers by the action of
`the dual diffusion screens 42 and 43, when it emerges
`from the light emitting screen 43.
`Light extraction fibers or light guides suitable for this
`embodiment have been described in copending applica-
`tion Ser. No. 07/813,972 (US. Pat. No. 5,222,795)
`which is included herein by reference. In that applica-
`tion, a method is described by means of systems in
`which the light conducted through the non-extracting
`segment of the fiber is extracted along the extraction
`zone at a predetermined extraction rate. One such ex-
`traction rate is when the light emitted per unit length of
`the extraction zone is constant. When such extraction
`fibers are used for the elements 46, 47 and 48 inside the
`luminaire 40 of the instant invention, the light emanat-
`ing from the light sources in the light bar is redistributed
`equally along the fibers within the light box 40.
`A better understanding of the structure of the em-
`bodiment shown in FIG. 3 can be gained by reviewing
`FIG. 4A which is a schematic cross section through a
`luminaire 40’ as shown in FIG. 3. Here the luminaire
`consists of three parallel sheets 41’, the base of the lumi-
`naire with a highly reflective inner surface, and the two
`sheets 42’ and 43’ on which is embossed (embossment
`not shown) a tessellation of light diffus patterns as de-
`scribed in copending application Ser. No. 07/813,972
`(US. Pat. No. 5,222,795). On the base surface 41' a
`plurality of groups 49' each containing three extraction
`fibers 46', 47’ and 48’, as described in copending applica-
`tion Ser. No. O7/8l3,972 (US. Pat. No. 5,222,795), are
`fastened.
`
`10
`cooling system including a circulating heat exchanging
`fluid entering the light bar via a tubular structure 54,
`and exiting the light bar via a second tubular structure
`55. A pump 56 forces the cooling fluid through the light
`bar and the heated fluid flows back through a heat
`exchanger 57 (which can be a simple radiator to the
`outer environment). The light sources are thermally in
`contact with the tubular structure 5 within the light bar
`so as to discharge the heat generated by the light
`sources to the cooling heat exchanging fluid. Good
`fluids for that purpose are electrical insulators, for