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
  • 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
  • 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
  • F21K9/61—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using light guides
• • 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
  • F21Y2103/00—Elongate light sources, e.g. fluorescent tubes
  • F21Y2103/10—Elongate light sources, e.g. fluorescent tubes comprising a linear array of point-like light-generating elements
• • 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]
• • 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
  • G02B6/0003—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 doped with fluorescent agents
• • 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
  • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/002—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces

Definitions

• the present invention relates to an LED illumination device.
• LED lamps use a single or multiple white LED light engines and LED light engines as light sources.
• the blue light emitted by the LED light engine is mixed with green and red light emitted by phosphors to obtain white light.
• Other solutions are to use converted greenish-white (mint) LED light engines in combination with red LEDs to gen ⁇ erate white light, and the so-generated white light has a low color temperature (2700K-4000K) , and higher color rendering index compared with pure phosphor conversion solutions.
• ⁇ ever, in all the solutions a portion of the light is lost by either direct emission or back-reflection onto the chip or into the LED package. Both of the chip and the LED package have a typical reflectivity below 90%.
• a solution providing high optical efficiency is the remote phosphor structure technique.
• a typical configuration is shown in Fig. 1.
• the light emitted from the blue LED light engine 1 travels to an opti- cal member, which is a remote phosphor structure 2 made of a transparent material (typically a polymer material, such as polycarbonate or PMMA, but other materials based on glass or ceramic are also feasible) filled with phosphor.
• Light con ⁇ version takes place in the remote phosphor structure in the same way as in the converted LED light engine. If the regions surrounding the LED light engine (i.e., all the portions of the space enclosed by the housing) are highly reflective, the light emitted or back-reflected from the lamp housing can be efficiently recycled.
• the temperature of the phosphor in the remote phosphor structure 2 will be lower than the temperature of the phosphor in the conventional LED package, resulting in higher conversion efficiency of the phosphor.
• the remote phosphor structure solution can be dozens of percent more efficient than similar solutions based on white LED package.
• the remote phosphor structure solution can be applied in some products, e.g., bulb-shaped LED retrofit lamps or Fortimo light engines, both from Philips. However, they have the fol ⁇ lowing three major disadvantages: 1.
• the consumption of phosphor for a remote phosphor structure is much higher than that for an ordinary converted LED. This is due to the requirement that, at a given conversion level, blue rays transmitting either the on-chip conversion layer or the remote phosphor structure need to hit the same number of phosphor particles.
• the amount of the phosphor scales with the area of the phosphor member, so the remote phosphor structure needs more phosphor. For some typical ap ⁇ plications, especially for warm-white solutions, phosphor cost can become a considerable part of the overall product cost for a remote phosphor structure solution.
• the remote phosphor structure Due to the high concentration of phosphor, the remote phosphor structure has a yellowish appearance, which is unde- sired for many applications. In some solutions, the remote phosphor structure is hidden under a semi-transparent hous- ing, which sacrifices efficiency. 3.
• the conversion process in the remote phosphor structure involves intrinsic losses, which generates heat and reduces the conversion efficiency of the phosphor. In many typical applications, the size of the remote phosphor structure mem- ber needs to be determined by a compromise between the cost (requiring a smaller size) and heat dissipation efficiency (requiring a larger size) .
• the present invention provides an LED illumination device.
• the LED illumination device according to the present invention has high light conversion efficiency, smaller size and low cost.
• an LED il ⁇ lumination device comprising an LED light engine, and a re- mote phosphor structure comprising a first emergent surface and an incident surface
• the remote phosphor struc ⁇ ture further comprises a second emergent surface disposed to face the first emergent surface, and at least one connection surface connected between the first emergent surface and the second emergent surface, and the connection surface is con ⁇ figured as the incident surface, wherein light from the LED light engine enters into the remote phosphor structure through the incident surface, and emerges through the first emergent surface and the second emergent surface.
• the LED il- lumination device can allow the light from the LED light engine to travel as far as possible in the remote phosphor structure, and as the travel ⁇ ling distance becomes longer, the light travelling in the re ⁇ mote phosphor structure can hit as much phosphor as possible in the remote phosphor structure, so as to achieve the pur ⁇ pose of efficiently converting the light, which advanta- geously reduces the amount of the phosphor in the remote phosphor structure, thereby largely reduces the manufacture cost of the remote phosphor structure, and further reduces the entire cost of the LED illumination device.
• the LED illumination device further comprises a reflector which is disposed to face the first emergent sur ⁇ face or the second emergent surface.
• the LED illumination de ⁇ vice is designed for projecting light onto a region with a predetermined range, and the arrangement of a reflector can advantageously reflect the light that may emit to an unde- sired region to the predetermined region to be illuminated, which largely improves the efficiency of the LED illumination device according to the present invention and reduces light loss .
• the remote phosphor structure comprises at least two connection surfaces, wherein one or more connection surfaces, which allow light to travel a longer distance in the remote phosphor structure, are configured as the incident surface.
• connection surfaces may have two or more con ⁇ nection surfaces, these connection surfaces all can be used as incident surfaces, however, if one or more of these con- nection surfaces allow the light to travel farthest in the remote phosphor structure, then the one or more connection surfaces are preferred as incident surfaces.
• the light from the connection surface (s) can hit the most phosphor in the remote phosphor structure, such that the remote phosphor structure of the LED illumination device according to the present invention can achieve the highest conversion effi ⁇ ciency .
• the remote phosphor structure is configured as an elongated body having an arc-shaped section, wherein the elongated body comprises an inner surface, an outer surface, and two opposite end surfaces serving as the connection sur ⁇ faces, which are connected between the inner surface and the outer surface and are in a longitudinal direction of the elongated body, and one or both end surfaces are configured as the incident surfaces.
• the remote phosphor structure is similar to a tube which is intercepted, i.e. a sector of a tube intercepted through a section along the longitudinal axis of the tube or a section parallel with this section.
• the LED illumination device using such a remote phosphor structure is advantageously used to, for example, replace a traditional lamp tube.
• one or both end surfaces of the elongated body, or the elongated sector are designed as the incident surfaces, such that the light can extend the longest distance in the elongated body, so as to hit the most phosphor, and further improves the light conversion efficiency of the entire remote phosphor structure .
• the remote phosphor structure is configured to be plate-like, wherein the remote phosphor structure comprises an upper surface and a lower surface which respectively serve as the first emergent surface and the second emergent sur- face, and four circumferential surfaces, opposite each other, which are connected between the upper surface and the lower surface as the connection surfaces, wherein one or more of the circumferential surfaces with the longest distance there- between are configured as the incident surfaces.
• this de ⁇ sign solution it is also necessary to make the light travel the longest distance in the remote phosphor structure, so two or more of the circumferential surfaces with the longest dis ⁇ tance therebetween are selected as the incident surfaces.
• This type of design solution can, for example, advantageously replace the conventional plate glass, when it does not work, it can serve as simple and transparent glass, and when it works, it can provide illumination.
• the remote phosphor structure comprises only one connection surface that is configured to be ring-like.
• the remote phosphor structure is configured to be bulb-like, wherein the bulb-like remote phosphor structure comprises an inner surface and an outer surface which serve as the first emergent surface and the second emergent surface, respectively, a ring-like support surface which is connected between the inner surface and the outer surface as the connection surface is formed at an open ⁇ ing end of the bulb-like remote phosphor structure, and the ring-like support surface is configured as the incident sur ⁇ face.
• the LED illumination device employing this type of re ⁇ mote phosphor structure is used to replace a traditional in ⁇ candescent lamp.
• the bulb-like re ⁇ mote phosphor structure comprises only one opening end, a ring-like support surface is formed at the opening end, and the light from the LED light engine enters into the remote phosphor structure from the ring-like support surface.
• the remote phosphor structure further com ⁇ prises a total internally reflective lens disposed on the in ⁇ cident surface, and at least a portion of light from the LED light engine enters into the remote phosphor structure through the incident surface after being totally internally reflected in the total internally reflective lens.
• the total internally reflective lens enables the light of the LED light engine to enter into the remote phosphor structure at a fa ⁇ vorable angle, such that the light extends as far as possible in the remote phosphor structure, which further improves the light conversion efficiency of the remote phosphor structure.
• the total internally reflective lens is con ⁇ figured to be ring-like, and comprises a lens incident sur ⁇ face and a lens emergent surface, wherein the lens emergent surface has the same shape as the ring-like support surface.
• Such type of total internally reflective lens is capable of guiding all the light of the LED light engine into the remote phosphor structure, which thereby further avoids light loss.
• the lens incident surface defines an accommoda- tion cavity for accommodating a luminous body of the LED light engine.
• the accommodation cavity completely encloses the luminous body, which prevents the light emitted by the luminous body from directly emitting to the ambient.
• the LED light engine com- prises a circuit board and at least one LED chip disposed on the circuit board, wherein the LED chip is disposed to face the incident surface.
• the LED chip is disposed to face the incident surface.
• the circuit board is at least partially formed as a reflector.
• the remote phosphor structure In the solution of configuring the remote phosphor structure to be bulb-like, as the bulb-like remote phos ⁇ phor structure will be disposed on the circuit board and sup ⁇ ported on the LED chip using the ring-like support surface, and the inner surface of the bulb will face the circuit board, it is very advantageous to configure a portion of the circuit board facing the inner surface as a reflector.
• the reflec ⁇ tor may be an independent reflective plate additionally pro- vided.
• the remote phosphor structure comprises a transparent body and phosphor filling the transparent body.
• the transparent body is made of polycarbonate, PMMA, glass or ceramic materials. It is to be understood that the features of the various exem ⁇ plary embodiments described herein may be combined with each other, unless specifically noted otherwise.
• FIG. 1 is a schematic diagram of an LED illumination device in the prior art, comprising a remote phosphor structure
• Fig. 2 is a schematic diagram of a first embodiment of the LED illumination device according to the present invention
• Fig. 3 is a schematic diagram of a second embodiment of the LED illumination device according to the present invention
• Fig. 4 is a schematic diagram of a third embodiment of the LED illumination device according to the present invention.
• Fig. 5 is a schematic diagram of an improved solution of the third embodiment of the LED illumination device according to the present invention.
• Fig. 2 is a schematic diagram of the first embodiment of the LED illumination device 100.
• the LED illumination device 100 comprises an LED light engine 1, and a remote phosphor structure 2 comprising a first emer- gent surface 21 and an incident surface 22, wherein the re ⁇ mote phosphor structure 2 further comprises a second emergent surface 23 disposed to face the first emergent surface 21, and at least one connection surface connected between the first emergent surface 21 and the second emergent surface 23, and the connection surface is configured as the incident sur ⁇ face 22, wherein light from the LED light engine 1 enters into the remote phosphor structure 2 through the incident surface 22, and emerges through the first emergent surface 21 and the second emergent surface 23.
• the remote phosphor structure 2 comprises a transparent body 25 and phosphor 26 filling the transparent body 25.
• the transparent body 25 is made of polycarbonate, PMMA, glass or ceramic materials.
• the remote phosphor structure 2 comprises at least two connection surfaces, wherein the connection surface, which allows light to travel a longer distance in the remote phosphor structure 2, is configured as the incident surface 22. In some other design solutions of remote phosphor structure 2, the remote phosphor structure 2 comprises only one connection surface that is configured to be ring-like.
• the remote phosphor structure 2 is configured as an elongated body having an arc-shaped section, wherein the elongated body comprises an inner surface, an outer surface, and two opposite end surfaces serving as the connection surfaces, which are connected between the inner surface and the outer surface and are in a longitudinal di ⁇ rection of the elongated body, the end surfaces being config ⁇ ured as the incident surfaces 22.
• the remote phosphor structure 2 comprises a plurality of con ⁇ nection surfaces. As can be seen from the figure, the remote phosphor structure 2 is similar to a tube which is inter- cepted, i.e.
• the LED illumination device 100 using such a remote phosphor structure 2 is advantageously used to, for example, replace a traditional lamp tube.
• the two end surfaces of the elongated body, or the elongated sector are designed as the incident surfaces 22, such that the light can extend the longest distance in the elongated body, so as to hit the most phosphor, and further improves the light conversion efficiency of the entire remote phosphor structure 2.
• the LED illumination device 100 further comprises a reflector.
• the region facing the first emergent sur ⁇ face 21 is a region to be illuminated, and thus, it is re ⁇ quired that all the light emerges through the first emergent surface 21.
• the reflector 3 is disposed to face the second emergent surface 23.
• the reflector 3 may be disposed to face the first emergent surface 21.
• the LED light engine 1 comprises a circuit board 11 and at least one LED chip 12 disposed on the circuit board 11, wherein the LED chip 12 is disposed to face the incident surface 22.
• the circuit board 11 is not shown for the purpose of simplification, and only the LED chip 12 is shown. However, this does not mean that there is no circuit board 11 in the embodiment shown in Fig. 2.
• the basic design principle of the present invention is to make the light travel as far as possible in the remote phos ⁇ phor structure.
• the object is: the light travelling in the remote phosphor structure 2 can hit as much phosphor 26 as possible in the remote phosphor structure 2, so as to achieve the purpose of efficiently converting the light, which advan ⁇ tageously reduces the amount of the phosphor 26 in the remote phosphor structure 2, thereby largely reduces the manufacture cost of the remote phosphor structure 2, and further reduces the entire cost of the LED illumination device 100. Further, since the amount of the phosphor 26 is reduced, the impact of the phosphor 26 on the color and appearance of the remote phosphor structure 2 is reduced, and the remote phosphor structure 2 of the LED illumination device 100 according to the present invention is nearly transparent.
• the temperature of the phosphor 26 is relatively low, which en ⁇ ables the remote phosphor structure 2 of the LED illumination device 100 according to the present invention to have higher conversion efficiency.
• a plurality of LED chips 12 are directly arranged on the two end surfaces of the elongated sector that have the longest distance therebetween, viz. the end surfaces of the two opening ends defining the tube.
• the light of the LED chip 12 enters into the remote phosphor structure 2, viz. the elongated body, from the end surfaces.
• the light incident at this position can travel the longest distance in the remote phosphor structure 2, and thereby hit the most phosphor 26.
• the remote phosphor structure 2 is actually similar to a light conduc ⁇ tor, the light entering the light conductor will be totally reflected between the two emergent surfaces, and further hit the phosphor 26, in order to excite the phosphor to emit light, the excited light is mixed with the light emitted by the LED chip 12 to obtain light having an expected color, e.g., the LED chip 12 emits blue light, and the yellow phos- phor is used, then white light is obtained.
• the light may also emerge from the second emergent surface 23, which is undesired as the region facing the first emergent surface 21 is expected to be the illuminated region, then an individual reflector 3 is provided, and the reflector 3 re- fleets the light emerging from the second emergent surface 23 back to the remote phosphor structure 2, and make the light emerge from the first emergent surface 21.
• Fig. 3 is a schematic diagram of a variant of a second em ⁇ bodiment of the LED illumination device 100 according to the present invention.
• the difference between the solution shown in Fig. 3 and the solution shown in Fig. 2 merely lies in the shape of the remote phosphor structure 2.
• the remote phosphor structure 2 is configured to be plate-like, wherein the remote phosphor structure 2 comprises an upper surface and a lower surface which re ⁇ spectively serve as the first emergent surface 21 and the second emergent surface 23, and four circumferential sur ⁇ faces, opposite each other, which are connected between the upper surface and the lower surface as the connection sur- faces, wherein two of the circumferential surfaces with the longest distance therebetween are configured as the incident surfaces 22.
• the remote phosphor structure 2 is actually a rectangular plate-like hexahedron, wherein four surfaces of the hexahedron having a smaller width serve as the circumferential surfaces of the remote phosphor structure 2, and the circumferential surfaces having a smaller length serve as the incident surfaces 22, and the LED chips are disposed on the circumferential surfaces.
• This type of solution can, for example, advantageously replace the conventional plate glass, when it does not work, it can serve as simple and transparent glass, and when it works, it can provide illumination.
• Fig. 4 is a schematic diagram of a third embodiment of the LED illumination device 100 according to the present invention.
• the remote phosphor structure 2 comprises only one connection surface, wherein the remote phosphor structure 2 is configured to be bulb-like, wherein the bulb-like remote phosphor structure 2 comprises an inner surface and an outer surface which serve as the first emer ⁇ gent surface 21 and the second emergent surface 23, respec ⁇ tively, a ring-like support surface which is connected be- tween the inner surface and the outer surface as the connec ⁇ tion surface is formed at an opening end of the bulb-like re ⁇ mote phosphor structure 2, and the ring-like support surface is configured as the incident surface 22.
• the LED chip 12 disposed on the circuit board 11 is not disposed within the bulb-like remote phosphor structure 2, that is, the space defined by the second emergent surface 23, but is disposed on the con ⁇ nection surface between the first emergent surface 21 and the second emergent surface 23.
• the light emitted by the LED chip 12 will enter into the remote phosphor structure 2 at the position of the connection surface.
• the light travels obviously farther in the remote phosphor structure 2, as compared with the prior art solution shown in Fig. 1.
• the circuit board 11 is at least partially formed as the reflector 3.
• the remote phosphor structure 2 which serves as a bulb will be disposed on the circuit board 11 and supported on the LED chip 12 using the ring-like support surface, and the inner surface of the bulb will face the circuit board 11, it is very advantageous to configure a portion of the circuit board 11 facing the inner surface as a reflector.
• Fig. 5 is a schematic diagram of an improved solution of the third embodiment of the LED illumination device 100 according to the present invention.
• the remote phosphor structure 2 further comprises a to ⁇ tal internally reflective lens 24 disposed on the incident surface 22, viz. the ring-shaped support surface, and at least a portion of light from the LED chip 12 enters into the remote phosphor structure 2 through the incident surface 22 after being totally internally reflected in the total inter ⁇ nally reflective lens 24.
• the total internally reflective lens 24 enables the light of the LED chip 12 to enter into the remote phosphor structure 2 at a favorable angle, such that the light extends as far as possible in the remote phos ⁇ phor structure 2, which further improves the light conversion efficiency of the remote phosphor structure 2.
• the total internally reflective lens 24 is configured to be ring-like, and com- prises a lens incident surface 241 and a lens emergent sur ⁇ face 242, wherein the lens emergent surface 242 has the same shape as the ring-like support surface.
• the lens incident surface 241 defines an accommodation cavity 243 for accommodating the LED chip 12.
• Such type of total internally reflective lens is capable of guiding all the light of the LED light engine into the remote phosphor structure 2, which thereby further avoids light loss.

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Citations (6)

• 2012
  • 2012-09-19 CN CN201210350905.2A patent/CN103672472A/zh active Pending
• 2013
  • 2013-08-29 WO PCT/EP2013/067913 patent/WO2014044513A1/en active Application Filing

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