Classifications

• • 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
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/20—Controlling the colour of the light
  • H05B45/28—Controlling the colour of the light using temperature feedback
• • 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
  • F21Y2113/00—Combination of light sources
  • F21Y2113/10—Combination of light sources of different colours
  • F21Y2113/13—Combination of light sources of different colours comprising an assembly of point-like light sources
• • 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

• This invention relates generally to lighting technology, and more particularly to light emitting diode (LED) light sources.
• LED light emitting diode
• warm white light having a color temperature of 2700K and 3000K (abbreviated to "2700/3000K” in the following paragraphs) can be obtained from a mix of blue light, yellow/green light and a huge amount of red light.
• warm white light can be produced by mixing the yellow/green light and the red light, which are generated by activating the nitride red fluorescent powder and phosphor with a portion of blue light emitted from the blue LED, with the unabsorbed blue light which passes through the nitride red fluorescent powder and phosphor.
• YAG yttrium aluminum garnet
• GaN gallium nitride
• the warm white LED light source can be constituted by packaging an array of phosphor-coated blue LEDs, for example a YAG-coated GaN-based blue LED array, with a red LED array, for example an aluminum indium gallium phosphide (AlInGaP) LED array.
• an array of phosphor-coated blue LEDs for example a YAG-coated GaN-based blue LED array
• a red LED array for example an aluminum indium gallium phosphide (AlInGaP) LED array.
• AlInGaP aluminum indium gallium phosphide
• the lighting efficiency of this approach is much higher, because the red LED array directly emits the red light, and the quality of the mixed warm white light is better.
• a blue LED has a different temperature-dependence of the lumen output as compared to that of the red LED, i.e. the lumen degradation of the red LED is much stronger than that of the blue LED as the junction temperature rises.
• the LED light source when the LED light source is in operation, that is, the junction temperature reaches a high level, a color point of the warm white light, mixed from the cold white light emitted from the phosphor-coated blue LED array and the red light emitted from the red LED array, may shift greatly.
• the observer may observe that the color of the warm white light source is more greenish or reddish.
• the color point of the warm white light, mixed from the cold white light emitted from the phosphor-coated blue LED array and the red light emitted from the red LED array can locate within 5 MacAdam ellipses of a color temperature of 2700/3000K on the black-body locus.
• a warm white LED light source constituted by packaging the phosphor-coated blue LED array with the red LED array is driven by a dual-channel driver.
• the lighting system having the LED light source is generally further equipped with a temperature sensor.
• the temperature sensor measures the junction temperature of the LED array and sends the temperature information to the dual-channel driver. Based on the received temperature information, the dual-channel driver adjusts the currents supplied to the phosphor-coated blue LED array and the red LED array, respectively, so that the ratio of the lumen output thereof remains in the range of 4.8: 1 to 3.8:1.
• the warm white LED light source driven by the dual-channel driver can make sure that the ratio of the lumen output of the phosphor-coated blue LED array to the lumen output of the red LED array remains in the range of 4.8: 1 to 3.8: 1 during its operation, however, since this type of lighting system adopting LED light sources includes the temperature sensor and the dual-channel driver, it is complicated in structure and the cost is higher.
• a light emitting diode light source comprises:
• a phosphor-coated blue light emitting diode array a color point of the mixed light emitted from the phosphor-coated blue light emitting diode array falling into a quadrilateral of the CIE chromaticity diagram, wherein coordinates of four vertices of the quadrilateral are (0.375, 0.427), (0.390, 0.456), (0.366, 0.430), (0.38, 0.46);
• the ratio of the lumen output of the phosphor-coated blue light emitting diode array to the lumen output of the red light emitting diode array is within a range of 4: 1 to 1.5: 1.
• the ratio of the lumen output of the phosphor- coated blue light emitting diode array to the lumen output of the red light emitting diode array may be within a range of 4.8:1 to 3.8: 1, so that the color point of the warm white light, mixed from the cold white light emitted from the phosphor-coated blue light emitting diode array and the red light emitted from the red light emitting diode array, can locate within 5 MacAdam ellipses of a color temperature of 2700/3000K on the black-body locus, and thus the quality of the warm white light emitted from the light emitting diode light source is efficiently improved.
• the quantity ratio and/or area ratio of the light emitting diodes of the phosphor-coated blue light emitting diode array to the light emitting diodes of the red light emitting diode array is adjusted such that the ratio of the lumen output of the phosphor-coated blue light emitting diode array to the lumen output of the red light emitting diode array is within a range of 4: 1 to 1.5: 1.
• the component ratio and/or grain size of the phosphor is adjusted such that the color point of the mixed light emitted from the phosphor-coated blue light emitting diode array falls within the quadrilateral.
• the peak emission wavelength of the blue light emitting diode array is set within a range of 440nm to 460nm.
• the blue light emitting diode array is a gallium nitride-based blue light emitting diode array.
• the peak emission wavelength of the red light emitting diode array (110) is set within a range of 600nm to 620nm.
• the red light emitting diode array is an AlInGaP light emitting diode array.
• the phosphor comprises YAG or TAG.
• a lighting apparatus comprises a single-channel driver and any of the light emitting diode light sources described above, wherein the light emitting diode light source is driven by the single-channel driver.
• Figure 1 is a schematic view of a light emitting diode light source 100 according to an embodiment of the present invention
• Figure 2 is a schematic view of a lighting apparatus 10 according to an embodiment of the present invention.
• Figure 3 is a CIE chromaticity diagram according to an embodiment of the present invention
• Figure 4 shows a layout of respective light emitting diodes of the light emitting diode light source 100 according to an embodiment of the present invention.
• Figure 1 is a schematic view of a light emitting diode light source 100 according to an embodiment of the present invention.
• FIG 2 is a schematic view of a lighting apparatus 10 according to an embodiment of the present invention.
• the lighting apparatus 10 comprises a single-channel driver 200 and the light emitting diode light source 100 of Figure 1.
• the light emitting diode light source 100 comprises a red light emitting diode array 110 and a phosphor-coated blue light emitting diode array 120.
• the red light emitting diode array 110 may include one or more red light emitting diodes, and similarly the blue light emitting diode array 120 may include one or more red light emitting diodes.
• the peak emission wavelength of the blue light emitting diode array 120 is set within a range of 440nm to 460nm.
• the blue light emitting diode array 120 comprises a gallium nitride-based blue light emitting diode array.
• the gallium nitride-based blue light emitting diode array includes, but is not limited to, a GaN blue light emitting diode array, a GaAIN blue light emitting diode array, an InGaN light emitting diode array, or an InAlGaN blue light emitting diode array.
• the peak emission wavelength of the red light emitting diode array 110 is set within a range of 600nm to 620nm.
• the red light emitting diode array 110 comprises an AlInGaP light emitting diode array.
• the phosphor comprises YAG ( Yttrium Aluminum Garnet) .
• the phosphor comprises TAG (Terbium Aluminum Garnet).
• the red light emitting diode array 110 and the phosphor-coated blue light emitting diode array 120 are coupled in series, and the operational current thereof is supplied by the single-channel driver 200.
• the operational current supplied by the single-channel driver 200 flows through the red light emitting diode array 110 and the phosphor-coated blue light emitting diode array 120, so that the arrays 110 and 120, respectively, are activated to emit light.
• a portion of the blue light emitted from the blue light emitting diode array 120 activates the phosphor coated thereon to emit yellow/green light, and the yellow/green light is mixed with unabsorbed blue light passing through the phosphor to generate cold white light.
• the cold white light emitted from the phosphor- coated blue light emitting diode array 120 is mixed with the red light emitted from the red light emitting diode array to form warm white light.
• the color point of the mixed light emitted from the phosphor-coated blue light emitting diode array 120 falls within a quadrilateral of a CIE chromaticity diagram of Figure 3.
• the coordinates of four vertices of the quadrilateral are (0.375, 0.427), (0.390, 0.456), (0.366, 0.430), (0.38, 0.46).
• the component ratio of the phosphor may be adjusted such that the color point of the mixed light emitted from the phosphor-coated blue light emitting diode array 120 falls within the quadrilateral.
• the grain size of the phosphor may be adjusted such that the color point of the mixed light emitted from the phosphor-coated blue light emitting diode array 120 falls within the quadrilateral.
• both the component ratio of the phosphor and the grain size of the phosphor may be adjusted such that the color point of the mixed light emitted from the phosphor-coated blue light emitting diode array falls within the quadrilateral.
• the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within a range of 4: 1 to 1.5:1.
• the room temperature is 25°C .
• room temperature of the present invention may allow a minor deviation from 25 °C .
• a predetermined duration of operational current supply to the phosphor-coated blue light emitting diode array 120 and the red light emitting diode array 110 is in the form of pulses, and the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is measured.
• the quantity ratio of the blue light emitting diodes of the phosphor-coated blue light emitting diode array 120 to the red light emitting diodes of the red light emitting diode array 110 is adjusted such that the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within a range of 4: 1 to 1.5: 1.
• the junction temperature of the light emitting diodes is substantially equal to room temperature, so that the accuracy of the measured ratio of the lumen output is ensured and thus the accuracy of the following adjustment to the ratio of the lumen output is ensured.
• the predetermined duration is from 5 to 100 ms.
• the predetermined duration is 25 ms.
• the duty ratio of the operational current supplied in the form of pulses ranges from 1% to 20%.
• the area ratio/total area ratio of the blue light emitting diodes of the phosphor-coated blue light emitting diode array 120 to the red light emitting diodes of the red light emitting diode array 110 may be adjusted such that the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within the range of 4:1 to 1.5: 1.
• both the quantity ratio and the area ratio of the blue light emitting diodes of the phosphor-coated blue light emitting diode array 120 to the red light emitting diodes of the red light emitting diode array 110 may be adjusted such that the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within the range of 4: 1 to 1.5: 1.
• the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within the range of 4: 1 to 1.5:1.
• the ratio of the lumen output of the phosphor-coated blue light emitting diode array 120 to the lumen output of the red light emitting diode array 110 is within a range of 4.8: 1 to 3.8: 1, so that the color point of the warm white light, mixed from the cold white light emitted from the phosphor-coated blue light emitting diode array 120 and the red light emitted from the red light emitting diode array 110, can locate within the 5 MacAdam ellipses of a color temperature of 2700/3000K on the black-body locus as shown in Figure 3.
• FIG 4 illustrates a layout of respective light emitting diodes of the light emitting diode light source 100 according to an embodiment of the present invention.
• the red light emitting diode array 110 of the light emitting diode light source 100 comprises a first red light emitting diode 1101 and a second red light emitting diode 1102, and the phosphor-coated blue light emitting diode array 120 comprises a first phosphor-coated blue light emitting diode 1201 and a second phosphor-coated blue light emitting diode 1202.
• each light emitting diodes of the light emitting diode light source 100 are set asymmetrically on a substrate.
• the first phosphor-coated blue light emitting diode 1201 is set on the left side of the substrate
• the first red light emitting diode 1101 and the second red light emitting diode 1102 are symmetrically set respectively on the upper side and lower side of the substrate
• the second phosphor-coated blue light emitting diode 1202 is set on the right side of the substrate.
• the phosphor-coated blue light emitting diode array 120 and the red light emitting diode array 110 are packaged onto a carrier substrate, for example a ceramic substrate with a single silicone lens encapsulation on all these two light emitting diode arrays.
• the phosphor-coated blue light emitting diode array 120 and the red light emitting diode array 110 are packaged onto a carrier substrate, for example a ceramic substrate with a silicone lens encapsulation on each individual light emitting diode array.
• a light emitting diode light source 100 is driven by a single-channel driver
• the light emitting diode light source is not limited to be driven by a single-channel driver, and it may also be driven by a dual-channel driver.
• the light emitting diode light source is driven by the dual-channel driver, it is relatively complicated in structure and the cost is higher.
• the light emitting diode light source of embodiments of the present invention, driven by the single-channel driver has the same lighting performance, further reduces the cost and simplifies the structure.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Optics & Photonics (AREA)
• General Engineering & Computer Science (AREA)
• Led Device Packages (AREA)
• Luminescent Compositions (AREA)

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• 2011
  • 2011-03-23 WO PCT/IB2011/051216 patent/WO2011121489A1/en active Application Filing
  • 2011-03-23 CN CN201180016997.4A patent/CN102812782B/zh not_active Expired - Fee Related
  • 2011-03-23 EP EP11716052.3A patent/EP2554018B1/en not_active Not-in-force
  • 2011-03-23 JP JP2013501997A patent/JP5805175B2/ja not_active Expired - Fee Related
  • 2011-03-23 PL PL11716052T patent/PL2554018T3/pl unknown
  • 2011-03-23 RU RU2012146737/07A patent/RU2557016C2/ru not_active IP Right Cessation

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