Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
  • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
  • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
  • F21K9/64—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S4/00—Lighting devices or systems using a string or strip of light sources
  • F21S4/20—Lighting devices or systems using a string or strip of light sources with light sources held by or within elongate supports
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
  • F21V9/30—Elements containing photoluminescent material distinct from or spaced from the light source
  • F21V9/38—Combination of two or more photoluminescent elements of different materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]

Definitions

• the present invention relates to an illumination device for simulating neon or similar lighting using a light source and phosphorescent dye.
• the illumination device may also ,) include a means for varying the intensity of the light source to produce certain color changing effects.
• Neon lighting which is produced by the electrical stimulation of the electrons in the low-pressure neon gas-filled glass tube, has been a main stay in advertising and for outlining channel letters and building structures for many years. A characteristic of neon lighting is that the tubing encompassing the gas has an even glow over its entire length irrespective of the viewing angle.
• a light source extends along and is positioned adjacent the light-receiving surface and spaced from the light-emitting surface a distance sufficient to create an elongated light intensity pattern with a major axis along the length of the rod and a minor axis that has a width that covers substantially the entire circumferential width of the light-emitting surface.
• the light source is a string of point light sources spaced a distance apart sufficient to permit the mapping of the light emitted by each point light source into the rod so as to create elongated and overlapping light intensity patterns along the light-emitting surface and circumferentially about the surface so that the collective light intensity pattern is perceived as being uniform over the entire light-emitting surface.
• a “leaky” waveguide is a structural member that functions both as an optical waveguide and light scattering member.
• the illumination device is described that uses fluorescent dyes, thus allowing for emission of light in colors that cannot ordinarily be achieved by use of LEDs alone without significant increase in cost or complexity of the illumination device.
• the illumination device is generally comprised of a rod-like member, a housing, and a light source.
• the rod-like member is a waveguide that has an external curved lateral surface serving as a light- emitting surface and an interior lateral surface that serves as a light-receiving surface, such that light entering the waveguide from the light source positioned below the light-receiving surface is scattered within the waveguide so as to exit with diffused distribution out of the curved lateral surface.
• the housing preferably comprises a pair of side walls that define an open-ended channel that extends substantially the length of the waveguide.
• the housing generally functions to house the light source and associated electrical accessories, and also preferably serves to collect and reflect light.
• a string or strings of contiguously mounted high-intensity light-emitting diodes is a preferred light source.
• LEDs high-intensity light-emitting diodes
• the illumination device is constructed so as to provide for emission of light with a perceived color or hue that is different than that ofthe LED itself. Specifically, this is accomplished through the incorporation of a light color or hue conversion system into the illumination device, specifically an intermediate light-transmitting medium extending along and positioned adjacent the light source.
• This intermediate light-transmitting medium is preferably composed of a substantially translucent acrylic, polyurethane or similar material tinted with a predetermined combination of one or more fluorescent dyes. Because ofthe position ofthe intermediate light-transmitting medium adjacent the light source, light emitted from the light source is directed into the intermediate light-transmitting medium and interacts with the fluorescent dyes contained therein. This light is partially absorbed by each ofthe fluorescent dyes of the intermediate light-transmitting medium, and light having a lower energy color or hue is then emitted from each ofthe fluorescent dyes and into the light-receiving surface ofthe waveguide.
• the present invention is an illumination device having a light source for emitting light of a predetermined first hue and a light-transmitting medium.
• the light- transmitting medium has a predetermined density of phosphorescent dye.
• the light-transmitting medium is positioned adjacent the light source such that an observer ofthe device perceives light that is of a hue that is different from the predetermined first hue.
• the light-transmitting medium acts as a color conversion system.
• the illumination device also includes a means for varying the intensity the light emitted by said light source, such that the perceived hue varies with a state of the light source.
• the means for varying the intensity ofthe light emitted by the light source could be a control device controlling a waveform of a power signal to said light source, including the shape, duty cycle, amplitude, and frequency ofthe power signal waveform.
• the shape ofthe power signal waveform could be, for example, a square wave or a sine wave.
• the light source is a plurality of light-emitting diodes (LEDs). Still further, the light-emitting diodes are arranged in an elongated pattern.
• the illumination device further has a waveguide positioned adjacent the light-transmitting medium.
• the waveguide is a substantially rod-like member having a light-receiving surface and a light-emitting surface. Further, the waveguide has both optical waveguide and light scattering properties. The light ofthe first hue and the light ofthe second hue are received by the light-receiving surface, and the perceived light is emitted from the light emitting surface.
• the light-transmitting medium is composed of a matrix of substantially translucent material doped with the predetermined density of phosphorescent dye. Then, several configurations are possible. In one configuration, a portion of the light emitted by the light source is transmitted through the light-transmitting medium without absorption by said dye.
• the light-transmitting medium has a first region that is substantially transparent, a second region that is doped with the predetermined density of a first phosphorescent dye, and a third region that is doped with a predetermined density of a second phosphorescent dye. Therefore, the perceived light of this configuration is a combination of: the first hue from light emitted by said light source passing through the first region; the second hue from light emitted by the dye from the second region; and a third hue from light emitted by the dye from the third region.
• the light-transmitting medium and the waveguide are essentially combined into a single element.
• the light-transmitting medium itself has optical waveguide and light scattering properties, an interior light-receiving surface for receiving said light ofthe first hue emitted by the light source; and an external curved light-emitting surface for emitting light ofthe perceived hue that is a combination of the light ofthe first hue and the light of the second hue.
• the illumination device further has a housing having a pair of side walls defining a channel. The light source is positioned within the channel, and the side walls have internal surfaces which reflect light into the light-transmitting medium.
• FIG. 1 is a block diagram of an exemplary illumination device according to the invention.
• FIG. 2 is a chart of phosphorescent light decay versus time for an exemplary phosphorescent dye.
• FIG. 3 is a block diagram of another exemplary illumination device according to the invention.
• FIG. 4 is a block diagram of yet another exemplary illumination device according to the invention.
• FIG. 5 is a CIE diagram tracing the perceived hue ofthe light emitted by an exemplary illumination device according to the invention.
• FIG. 6 is a perspective view of an exemplary illumination device according to the invention. [0026] FIG.
• FIG. 7 is perspective view with selected portions cut-away of the exemplary illumination device of FIG. 6.
• FIG. 8 is a sectional view of an exemplary illumination device according to the invention, similar to the illumination device of FIG. 6.
• FIG. 9 is a sectional view of an alternate embodiment of an illumination device according to the invention.
• FIGS. 10a - 10c are sectional views of another alternate embodiment of an illumination device according to the invention, illustrating various states of operation.
• FIG. 11 is a sectional view of yet another alternate embodiment of an illumination device according to the invention.
• the present invention is an illumination device for simulating neon or similar lighting using a light source and phosphorescent dye, and that also has a means for varying the intensity ofthe light emitted by the light source to produce certain color changing effects in the device.
• FIG. 1 is a block diagram of an exemplary illumination device according to the invention.
• the exemplary illumination device has a light source 12, a light-transmitting medium 14, a waveguide 16, and a means 18 for varying the intensity ofthe light emitted by light source 12.
• the light source 12 is for emitting light of a first predetermined hue, as discussed above.
• the preferred light source 12 is a plurality of light-emitting diodes (LEDs).
• the LEDs are arranged in a series to form an elongated pattern for the simulation of neon lighting; however, alternate configurations are certainly possible within the spirit and scope ofthe claimed invention.
• the light- transmitting medium 14 has a predetermined density of phosphorescent dye.
• Phosphorescent dye similar to the fluorescent dye described above, absorbs light having a higher energy color or hue, and then emits light having a lower energy color or hue.
• fluorescent dyes which can emit their light in picoseconds
• phosphorescent dyes absorb and emit light at a much slower rate.
• the light-transmitting medium 14 is positioned adjacent the light source 12 for receiving light emitted from the light source 12.
• the phosphorescent dye ofthe light- transmitting medium 14 will emit light of a second color or hue following absorption of light of the first hue from the light source 12.
• the light-transmitting medium 14 is further positioned such that an observer of the device perceives light that is different than the predetermined first hue ofthe light source 12. As shown in the embodiment of FIG.
• the perceived light will be of a color or hue that is a combination of the first hue and the second hue.
• the perceived light will be of the second color or hue only. In either case, the perceived light will be different than the predetermined first hue ofthe light source 12.
• FIG. 3 shows another exemplary illumination device having an alternate cooperation between the light source 1 12, the light-transmitting medium 114, and the waveguide 116. In this configuration, a portion ofthe light emitted by the light source 112 passes around the light-transmitting medium 114 and reaches the waveguide 116 directly, without passing through the light-transmitting medium 114. An observer ofthe device would still perceive light that is of a color or hue that is a combination of the first hue and the second hue.
• FIG. 3 shows another exemplary illumination device having an alternate cooperation between the light source 1 12, the light-transmitting medium 114, and the waveguide 116. In this configuration, a portion ofthe light emitted by the light source 112 passes around the light-transmitting medium 114 and reaches the waveguide 116 directly, without passing through the light-transmitting medium 114. An observer ofthe device would still perceive light that is of a color or hue that is a combination of the first hue and the second hue.
• the exemplary illumination device of FIG. 4 has a waveguide 215 that has a predetermined density of phosphorescent dye.
• the waveguide 215 has both optical waveguide and light scattering properties, and is positioned adjacent the light source 212 for receiving light ofthe first hue.
• the density of phosphorescent dye in the waveguide 215 can be selected such that the phosphorescent dye will absorb only a portion of light ofthe first hue and emit light of a second hue. Thus, a portion ofthe light ofthe first hue will not be absorbed by the phosphorescent dye, resulting in a perceived hue that is a combination of light ofthe first hue and light of the second hue.
• the density of phosphorescent dye in the waveguide 215 can be selected such that the phosphorescent dye will absorb all ofthe light ofthe first hue. Thus, the perceived hue will contain only light ofthe second hue emitted by the phosphorescent dye. In either case, the characteristics of the waveguide 215 will provide a uniform light intensity pattern along the waveguide 215.
• Any ofthe exemplary illumination device configurations described herein could also have fluorescent dyes, as described in commonly assigned and co-pending U.S. Patent Application No. 10/455,639, in addition to the subject phosphorescent dye. Additionally, it should be understood that phosphorescent dye described could also include a combination of individual dyes. This description is intended to cover all combinations and perturbations between fluorescent and phosphorescent dyes.
• the means 18, 118, 218 for varying the intensity, of the light emitted by the light source 12, 112, 212 will create various effects ofthe perceived hue varying with the state of the light emitted by the light source. For instance, when the light source 12, 112, 212 is on in a continuous state, the perceived hue will be a fixed combination ofthe first hue and the second hue. When the light source 12, 112, 212 is then removed or switched off, the phosphorescent dye will continue to emit light in the second hue only. This characteristic could serve as a useful safety feature in the event of a power failure, where the phosphorescent dye would continue to emit light.
• this characteristic can be utilized to produce a two color system by pulsing the light such that the perceived hue alternates between the composite hue and the second hue alone. Still further effects can be achieved by controlling the waveform ofthe power signal to the. light source. For instance, a power signal in the shape of a sine wave having a period similar to the decay time of the phosphorescent dye will cause the intensity of the light source 12, 112, 212 to vary corresponding to the power signal. The light emitted by the phosphorescent dye will also vary in response to the varying intensity of the light source 12, 112, 212.
• Means 18, 118, 218 for varying the intensity ofthe light emitted by the light source 12, 112, 212 are know in the art, and include: switching power supplies; function or waveform generators; rheostats or dimmer-switches; and simple on-off switches.
• Such means 18 are preferably capable of generating pulses or other power signal waveforms, including square waves and sine waves. Also, such means 18, 118, 218 are most likely capable of controlling the characteristics, such as the shape, duty cycle, amplitude and frequency ofthe power signal waveform.
• FIG. 5 shows a CIE diagram where a line 50 traces the perceived hue ofthe light emitted by an exemplary illumination device according to the invention using blue LEDs and a red phosphorescent dye.
• a power signal in the shape of a sine ave drives the LEDs.
• the period of sine wave and the decay time ofthe phosphorescent dye should be similar to create the color changing effect observed.
• the blue LEDs emit light of a first hue, represented by a first point 52.
• a second point 54 represents the perceived hue when the LEDs are operated at a constant, full-output (or DC) state.
• FIGS. 6 - 8 show an embodiment of an exemplary illumination device 310 according to the invention.
• the exemplary illumination device 310 is generally comprised of a light source 312, a light-transmitting medium 314, and a waveguide 316.
• a means for varying the intensity ofthe light emitted by the light source, as described above, would be operatively connected to the illumination device 310, but for convenience is not shown.
• the preferred light source 312 is a plurality of light- emitting diodes. (LEDs) having a first predetermined hue.
• the LEDs utilized in the exemplary embodiment discussed herein are high-intensity, blue-colored LEDs having a hue of approximately 465 - 470 nm. Blue is a higher energy color in the spectrum, and the availability of high-intensity, high-output LEDs in this color makes them preferable for exciting phosphorescent dyes for emitting a range of lower-energy hues, and, therefore, producing a range of perceived hues.
• the LEDs can be arranged in an elongated pattern to form a string or strings of lights to facilitate the simulation of a neon tube.
• the LEDs can be mounted on a circuit board in a substantially linear array or series, as shown.
• the light-transmitting medium 314 ofthe exemplary illumination device 310 is an intermediate member extending along and positioned adjacent the light source 312.
• the light- transmitting medium 314, as shown, has a light-receiving surface 320 for receiving light emitted from said light source 312 and a light-emitting surface 322 for emitting light into the waveguide 316.
• the light-transmitting medium 314 is, in effect, a color conversion system where the phosphorescent dye absorbs light of a first hue emitted by said light source 312, and emits light of a second, lower-energy hue.
• the light-transmitting medium 314 is preferably composed of a matrix of a substantially translucent acrylic, polyurethane, or similar material doped or tinted with a predetermined density ofthe phosphorescent dye.
• a preferred polyurethane for this application is a polyurethane manufactured and distributed by IPN Industries, Inc. of Haverhill,
• An exemplary dye is CP2-35 Fire Red Acrylic Lacquer glow-in-the-dark paint, manufactured and distributed by Risk Reactor of Huntington Beach, California.
• alternate configurations ofthe light-transmitting medium 314 and other dyes or combinations of dyes are possible and covered under both the spirit and the scope of the claimed invention.
• the phosphorescent dye ofthe light-transmitting medium 314 will continue to emit some amount of the lower-energy light even after the light source 312 stops emitting. Thus, if there is a power failure, the illumination device 310 will continue to provide some illumination from the phosphorescent dye ofthe intermediate light-transmitting medium 314, which is a useful safety feature.
• the waveguide 316 is a substantially rod-like member that preferably has an external curved surface 324 serving as a light-emitting surface and an interior surface 326 that serves as a light-receiving surface. Light entering the waveguide 316 from the light-transmitting medium 314 positioned below the light-receiving surface 324 is scattered within the waveguide 316 so as to exit with a diffused distribution out ofthe external curved surface 324.
• the external curved surface 324 aids in simulating the appearance of a neon tube.
• a housing 328 preferably comprises a pair of side walls 330, 332 that define an open-ended channel that extends substantially the length of waveguide 316.
• the housing 328 generally functions to house the light source 312 and associated electrical accessories (e.g., a circuit board). Further, the side walls 330, 332 may have internal surfaces having collection surfaces for collecting and reflecting light into said light-transmitting medium 314.
• the channel defined by the housing 328 is partially filled with a white potting compound 338 below the light source 312 to reflect light upwardly toward the waveguide 316.
• a portion ofthe volume ofthe open-ended channel is also filled with a translucent potting compound 336 that partially encapsulates the light source 312 and maintains the position of the light source 312 relative to the housing 328.
• the potting compound 336 should have an index of refraction essentially matching the index of refraction ofthe light source 312 to minimize Fresnel losses at the interface.
• a coating 414 containing phosphorescent dye is applied to the internal surface 426 of the waveguide 416.
• a coating containing phosphorescent dye could be applied to the external curved surface 424 ofthe waveguide 416.
• the waveguide 416 itself could be doped with said phosphorescent dye.
• FIGS. 10a - 10c show another alternate embodiment having a light source 512, a light-transmitting medium 514 and a waveguide 516, where a portion ofthe light emitted by the light source 512 passes around the light-transmitting medium 514 and reaches the waveguide 516 directly.
• FIG. 10a - 10c show another alternate embodiment having a light source 512, a light-transmitting medium 514 and a waveguide 516, where a portion ofthe light emitted by the light source 512 passes around the light-transmitting medium 514 and reaches the waveguide 516 directly.
• FIG. 10a shows an initial state where the light source 512 is first turned on, the phosphorescent dye in the light-transmitting medium 514 is "charging", and a portion ofthe light emitted by the light source 512 passes around the light-transmitting medium 514 and reaches the waveguide 516 directly. The light emitted by the device will be perceived as having a hue favoring the first hue ofthe light source.
• FIG. 10b shows a state where the light source 512 and the phosphorescent dye in the light-transmitting medium 514 are both emitting light into the waveguide 516. The light emitted by the device will be perceived as having a hue that is a combination of the first hue ofthe light source and the second hue of the phosphorescent dye.
• FIG. 10c shows a state where the light source 512 has just been turned off, and the phosphorescent dye continues to emit or "discharge" light of a second hue.
• the intensity ofthe light emitted by the light source 512 and timing it with the charging and discharging of the phosphorescent dye the light emitted by the device will be perceived as having a hue that is a combination ofthe intensities ofthe first hue ofthe light source and the second hue ofthe phosphorescent dye.
• FIG. 11 shows yet another alternate embodiment having a light source 612, a light transmitting medium 614 and a waveguide 616, where the light-transmitting medium 614 has a first region 640 that is substantially transparent, a second region 642 that is doped with a predetermined density of a first phosphorescent dye, and a third region 644 that is doped with a predetermined density of a second phosphorescent dye.
• the light-transmitting medium 614 has a first region 640 that is substantially transparent, a second region 642 that is doped with a predetermined density of a first phosphorescent dye, and a third region 644 that is doped with a predetermined density of a second phosphorescent dye.
• doping the second region 642 with a long-lived (i.e., slow emitting) red emitting phosphorescent dye and doping the third region 644 with a shorter-lived (i.e., more quickly emitting) red emitting phosphorescent dye will enhance the red characteristic of the perceived light and stretch it out.
• doping the second region 642 with a red emitting phosphorescent dye, doping the third region 644 with a green or yellow emitting phosphorescent dye, and using blue LEDs will, in effect, create a red, green, blue, or a red, yellow, blue system allowing a larger range of perceived colors, including white.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Optics & Photonics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Spectroscopy & Molecular Physics (AREA)
• General Physics & Mathematics (AREA)
• Illuminated Signs And Luminous Advertising (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=34748920

Family Applications (1)

Country Status (3)

Families Citing this family (5)

Citations (7)

Family Cites Families (2)

• 2004
  • 2004-12-29 EP EP04815860A patent/EP1706665A4/de not_active Withdrawn
  • 2004-12-29 CN CNA2004800395797A patent/CN1902434A/zh active Pending
  • 2004-12-29 WO PCT/US2004/043867 patent/WO2005065356A2/en active Application Filing

Patent Citations (7)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events