WO2013136250A1 - An led device comprising a cooling liquid with suspended phosphor particles - Google Patents

An led device comprising a cooling liquid with suspended phosphor particles Download PDF

Info

Publication number
WO2013136250A1
WO2013136250A1 PCT/IB2013/051909 IB2013051909W WO2013136250A1 WO 2013136250 A1 WO2013136250 A1 WO 2013136250A1 IB 2013051909 W IB2013051909 W IB 2013051909W WO 2013136250 A1 WO2013136250 A1 WO 2013136250A1
Authority
WO
WIPO (PCT)
Prior art keywords
light emitting
emitting device
liquid
liquid material
vessel
Prior art date
Application number
PCT/IB2013/051909
Other languages
French (fr)
Inventor
George Hubert BOREL
Jorgen Meeusen
Original Assignee
Koninklijke Philips N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips N.V. filed Critical Koninklijke Philips N.V.
Publication of WO2013136250A1 publication Critical patent/WO2013136250A1/en

Links

Classifications

    • 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
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • 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
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/60—Cooling arrangements characterised by the use of a forced flow of gas, e.g. air
    • F21V29/67—Cooling arrangements characterised by the use of a forced flow of gas, e.g. air characterised by the arrangement of fans
    • 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
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/56—Cooling arrangements using liquid coolants
    • F21V29/58—Cooling arrangements using liquid coolants characterised by the coolants
    • 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
    • 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]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/64—Heat extraction or cooling elements
    • H01L33/648—Heat extraction or cooling elements the elements comprising fluids, e.g. heat-pipes

Definitions

  • An LED device comprising a cooling liquid with suspended phosphor particles
  • the present invention relates to a light emitting unit comprising a lighting vessel for containing a liquid material, and a light source comprising at least one light emitting diode, at least the light emitting part of the light emitting diode being positioned in the lighting vessel to be in heat conductive connection with the liquid material.
  • the present invention further relates to a light emitting device comprising the light emitting unit.
  • LEDs Light emitting diodes will in the following i.a. be referred to as LEDs.
  • LEDs light emitting diodes
  • This cooling is usually provided on the non light emitting side of the LEDs by the use of heat sinks.
  • a lot of applications are using a phosphor attached to the LED, to convert the light of the LEDs this leaves a heat transfer path starting at the phosphor, which is the thermal hotspot, all the way down through the LEDs to the heat sink resulting in a high thermal resistance.
  • a phosphor material or a phosphor is a substance that exhibits the phenomenon of luminescence.
  • JP-A-20084689 discloses a light emitting diode package comprising a case member housing an LED and a liquid refrigerant surrounding the LED. Phosphor particles are suspended in the refrigerant, and in use the refrigerant transfers heat from the LED to the walls of the casing member by convection. From the walls of the casing member the heat is transferred on to the surroundings.
  • the casing member is mounted together with the LED on a printed circuit board.
  • a light emitting unit as mentioned in the introductory paragraph which is characterized in that the lighting vessel comprises a liquid inlet and a liquid outlet.
  • the liquid inlet and outlet allow for flowing liquid material through the lighting vessel to cool the light emitting diode and subsequently transfer the liquid material to a different place for cooling the liquid material at a place where disposal of the heat does not pose a problem.
  • This further provides freedom of design when the light emitting device of the invention is to be incorporated as a light source in a lighting aggregate i.a. because the light emitting device may be build small relative to its power and does not need to be directly attached to a heat sink.
  • the light emitting diode is positioned to be in physical contact with the liquid material. This facilitates heat transfer from the light emitting diode to the liquid.
  • a layer of solid material is isolating the light emitting diode from physical contact with the liquid material, said layer providing for conduction of heat between the light emitting diode and the liquid material. This facilitates sealing a liquid circuit comprising the lighting vessel.
  • the solid material may comprise a thin layer of silicone material.
  • electromagnetic radiation by convection of a fluid, e.g. liquid, material, and by conduction (through a material).
  • the invention utilises the latter to transfer heat from the LED to the liquid material. Once the heat has entered the liquid material the heat is carried away from the LED by convection of the liquid.
  • a light emitting device in that the lighting vessel of a light emitting unit is connected by the liquid outlet and the liquid inlet to a circuit comprising a heat transfer surface.
  • the heat transfer surface may provide for disposal of the heat.
  • the heat transfer surface is provided by a heat exchanger.
  • the circuit comprises a pump. Hereby circulation of the liquid material is facilitated independently on the mutual position of the lighting vessel and heat transfer surface.
  • the circuit comprises an expansion vessel.
  • thermal expansion of the liquid material may be absorbed.
  • the expansion vessel is provided by a hydrophore.
  • a certain pressure may be maintained in the circuit.
  • the circuit is moisture proof sealed.
  • the circuit of the light emitting device including the lighting vessel may contain a liquid material, which may be selected from a group
  • liquid material comprising oils, paraffin, and chlorinated paraffin.
  • a binder may be comprised preventing the paraffin or chlorinated paraffin from separating.
  • incorporating the lighting vessel in a liquid circuit with a heat transfer surface for cooling a very effective cooling of the light emitting diode is provided for facilitating an increased luminous flux output using a high power LED.
  • particles of a phosphor material are suspended in the liquid material.
  • the liquid material with the phosphor material serves as an optical volume diffuser converting and diffusing the light emitted by the light emitting diode.
  • Further effective cooling of the phosphor material is obtained due to the phosphor material circulating with the liquid material past the heat transfer surface to be cooled together with the liquid material.
  • the particles of phosphor material comprise microscopic particles.
  • the phosphor material particles are not individually visible and emission of uniformly diffused light by the light emitting device is facilitated.
  • the phosphor material comprises at least one phosphor component selected from a group comprising organic phosphors, inorganic yellow-green phosphors, and reddish inorganic phosphors.
  • the inorganic yellow-green phosphors may be selected from a group comprising YAG and Luag SSONE, and the reddish inorganic phosphors may be selected form a group comprising ECAS101, ECAS102, and BSSNe.
  • FIG. 1 shows a diagram of a light emitting device according to the invention
  • Fig. 2 shows a section of an embodiment of a light emitting unit
  • Fig. 3 shows a section of a different embodiment of a light emitting unit.
  • Fig. 1 shows a light emitting device comprising a light emitting unit 1 with a lighting vessel 3 having a bottom 5 and a transparent or translucent top wall 7. At the bottom 5 a plurality of light emitting diodes (LEDs) 9 are provided, the LEDs 9 having respective light emitting parts 11 facing the top wall 7.
  • the lighting vessel 3 has a liquid inlet 13 and a liquid outlet 15.
  • the light emitting device further comprises a heat exchanger 17 with a heat transfer surface 19 and a fan 21; a pump 23; and a reservoir tank embodied as a hydrophore 25.
  • Conduits 27 connect the above elements of the light emitting device to provide a circuit.
  • a first conduit 27a connects the liquid outlet 15 of the lighting vessel 3 and the heat exchanger 17
  • a second conduit 27b connects the heat exchanger 17 and the hydrophore 25
  • a third conduit 27c connects the hydrophore 25 and the pump 23
  • a forth conduit 27d connects the pump 23 and the liquid inlet 13 of the lighting vessel 3.
  • the circuit thus provided by the lighting vessel 3, the heat exchanger 17, the hydrophore 25 and the pump 23 is filled with a liquid material 29, such an oil material, having particles of a phosphor material suspended therein as indicated by dots 31 in the lighting vessel 3.
  • the light emitting parts 11 of the LEDs 9 are in physical contact with the liquid material 29 in the lighting vessel 3. Thereby the light emitting parts 11 of the LEDs 9 are in heat conductive connection with the liquid material 29, which thus provides for cooling the LEDs 9.
  • a thin layer 33 of solid material or sheet, such as a silicone material, is isolating the LED's 9 from physical contact with the liquid material 29.
  • the light emitting parts 11 of the LEDs 9 are in heat conductive connection with the liquid material 29, the layer 33 of solid material conducting heat from the LED's 9 to the liquid material 29, which thereby provides for cooling the LED's 9.
  • the layer 33 of e.g. silicone material facilitates the provision of a sealed, especially moisture proof sealed lighting vessel 3 (apart from the liquid inlet and liquid outlet), which is beneficial if the phosphor material used is degradable by moisture.
  • the LEDs 9 may e.g. be of InGaN-type providing light of Royal Blue color.
  • the liquid material 29 may be chosen from a group comprising oils, paraffin, and chlorinated paraffin. When paraffin or chlorinated paraffin is used a binder may be added to prevent the paraffin or chlorinated paraffin from separating. Such measure is per se known in the art.
  • the liquid material should be liquid at the surrounding temperature where the light emitting device is intended to be used.
  • the phosphor material may e.g. be chosen from group comprising organic phosphors, inorganic yellow- green phosphors, i.e. phosphors emitting light in the yellow-green range, such as e.g. YAG and Luag SSONE, and reddish inorganic phosphors, i.e. phosphors emitting reddish light, such as e.g. ECAS101, ECAS102, and BSSNe.
  • the actual phosphor to be chosen may depend on the actual type of LEDs used to provide for the light emitting unit to emit light of an intended color.
  • the size distribution of the particles of phosphor material may vary from microscopic particles that will give the respective liquid material a uniform diffuse glove when illuminated by the LED's, to macroscopic particles that will be individually visible.
  • Microscopic particles may have sizes ranging from nano-scale to e.g. 100 ⁇ . Macroscopic individually visible particles may provide for inspection of whether the liquid material is flowing through the lighting vessel 3.
  • the liquid material 29 and the phosphor material 31 may be chosen to have similar densities to provide for the particles of phosphor material 31 to float in the liquid material 29. However the circulating movement of the liquid material 29 will provide for stirring up the particles of phosphor material 31 facilitating their suspension in the liquid material 29.
  • the hydrophore 25 provides for maintaining an overpressure in the circuit which e.g. is beneficial when the embodiment shown in Fig. 3 of the lighting unit 1 is used, since the overpressure will ensure contact between the sheet or layer 33 and the light emitting parts 11 of the LEDs 9 thereby providing for good transfer of heat from the LEDs 9 to the layer 33 from where the heat is further transferred to the liquid material 29.
  • the LEDs 9 emit light towards the top wall 7 through the liquid material 29 and the particles of phosphor material 31 convert the light or at least a part thereof, before it is transmitted through the top wall 7.
  • the liquid material 29 with the particles of phosphor material 31 suspended therein acts as a volume diffuser providing for light mixing.
  • the pump 23 circulates the liquid material 29 from the lighting vessel 3 to the heat exchanger 17 for the liquid material 29 to pass the heat transfer surface 19 which is cooled by surrounding air driven by the fan 21.
  • the liquid material 29 thus cooled is then circulated from the heat exchanger 17 through the hydrophore 25 and the pump 23 back to the lighting vessel 3.
  • the invention provides freedom of design for a designer who is constructing a lighting implement incorporating a light emitting device since the light emitting unit may be quite small not needing to be attached to a solid heat sink and accordingly and may be placed in a confined space with reduced circulation of surrounding air to cool the light emitting unit while the other components of the light emitting device may be placed remote from the light emitting unit where space is available.
  • a pressure less expansion vessel may be used as the reservoir tank instead of the hydrophore shown.
  • the reservoir tank whether embodied as a hydrophore or not, may be attached to a blind end branch instead of having the liquid material flowing continuously through.
  • LEDs other types of liquid material and other types of phosphor material than the types specifically mentioned may be used.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Led Device Packages (AREA)
  • Arrangement Of Elements, Cooling, Sealing, Or The Like Of Lighting Devices (AREA)

Abstract

A light emitting unit (1) comprises a lighting vessel (3) for containing a liquid material (29), and a light source comprising at least one light emitting diode (9), at least the light emitting part (11) of the light emitting diode (9) being positioned in the lighting vessel (3) to be in heat conductive connection with the liquid material (29). The lighting vessel (3) comprises a liquid inlet (13) and a liquid outlet (15). In an embodiment the lighting vessel (3) is connected by the liquid outlet (15) and the liquid inlet (13) to a circuit comprising a heat transfer surface (19).

Description

An LED device comprising a cooling liquid with suspended phosphor particles
FIELD OF THE INVENTION
The present invention relates to a light emitting unit comprising a lighting vessel for containing a liquid material, and a light source comprising at least one light emitting diode, at least the light emitting part of the light emitting diode being positioned in the lighting vessel to be in heat conductive connection with the liquid material.
The present invention further relates to a light emitting device comprising the light emitting unit.
BACKGROUND OF THE INVENTION
Light emitting diodes will in the following i.a. be referred to as LEDs.
In lighting applications that incorporates light emitting diodes (LEDs), especially high power LEDs, there is a need for cooling. This cooling is usually provided on the non light emitting side of the LEDs by the use of heat sinks. A lot of applications are using a phosphor attached to the LED, to convert the light of the LEDs this leaves a heat transfer path starting at the phosphor, which is the thermal hotspot, all the way down through the LEDs to the heat sink resulting in a high thermal resistance.
It should be noted that generally a phosphor material or a phosphor, is a substance that exhibits the phenomenon of luminescence.
JP-A-20084689 discloses a light emitting diode package comprising a case member housing an LED and a liquid refrigerant surrounding the LED. Phosphor particles are suspended in the refrigerant, and in use the refrigerant transfers heat from the LED to the walls of the casing member by convection. From the walls of the casing member the heat is transferred on to the surroundings. The casing member is mounted together with the LED on a printed circuit board. Thus this piece of prior art involves the problem that the outside of the walls of the casing member need to be cooled and a problem of cooling is still attached to the area of the printing circuit board where the LED is mounted.
SUMMARY OF THE INVENTION It is an object of the present invention to overcome this problem, and to provide a light emitting unit and a light emitting device allowing use of high power LEDs.
According to a first aspect of the invention, this and other objects are achieved by a light emitting unit as mentioned in the introductory paragraph which is characterized in that the lighting vessel comprises a liquid inlet and a liquid outlet. The liquid inlet and outlet allow for flowing liquid material through the lighting vessel to cool the light emitting diode and subsequently transfer the liquid material to a different place for cooling the liquid material at a place where disposal of the heat does not pose a problem. This further provides freedom of design when the light emitting device of the invention is to be incorporated as a light source in a lighting aggregate i.a. because the light emitting device may be build small relative to its power and does not need to be directly attached to a heat sink.
In an embodiment the light emitting diode is positioned to be in physical contact with the liquid material. This facilitates heat transfer from the light emitting diode to the liquid.
In another embodiment a layer of solid material is isolating the light emitting diode from physical contact with the liquid material, said layer providing for conduction of heat between the light emitting diode and the liquid material. This facilitates sealing a liquid circuit comprising the lighting vessel. The solid material may comprise a thin layer of silicone material.
It is noted that generally heat are transferred in three different ways, namely by
(electromagnetic) radiation, by convection of a fluid, e.g. liquid, material, and by conduction (through a material). The invention utilises the latter to transfer heat from the LED to the liquid material. Once the heat has entered the liquid material the heat is carried away from the LED by convection of the liquid.
According to a second aspect of the invention a light emitting device is provided in that the lighting vessel of a light emitting unit is connected by the liquid outlet and the liquid inlet to a circuit comprising a heat transfer surface. Hereby the heat transfer surface may provide for disposal of the heat.
In an embodiment the heat transfer surface is provided by a heat exchanger. In an embodiment the circuit comprises a pump. Hereby circulation of the liquid material is facilitated independently on the mutual position of the lighting vessel and heat transfer surface.
In an embodiment the circuit comprises an expansion vessel. Hereby thermal expansion of the liquid material may be absorbed. In a further embodiment the expansion vessel is provided by a hydrophore. Hereby a certain pressure may be maintained in the circuit.
In an embodiment the circuit is moisture proof sealed.
Put into practical use the circuit of the light emitting device including the lighting vessel may contain a liquid material, which may be selected from a group
comprising oils, paraffin, and chlorinated paraffin. If the liquid material comprises a liquid component selected from a group comprising paraffin and chlorinated paraffin, a binder may be comprised preventing the paraffin or chlorinated paraffin from separating. By
incorporating the lighting vessel in a liquid circuit with a heat transfer surface for cooling a very effective cooling of the light emitting diode is provided for facilitating an increased luminous flux output using a high power LED.
In an embodiment particles of a phosphor material are suspended in the liquid material. Hereby is obtained that the liquid material with the phosphor material serves as an optical volume diffuser converting and diffusing the light emitted by the light emitting diode. Further effective cooling of the phosphor material, which is a hot spot in a system using phosphor converted light from LED's, is obtained due to the phosphor material circulating with the liquid material past the heat transfer surface to be cooled together with the liquid material.
In an embodiment the particles of phosphor material comprise microscopic particles. Hereby is obtained that the phosphor material particles are not individually visible and emission of uniformly diffused light by the light emitting device is facilitated.
In an embodiment the phosphor material comprises at least one phosphor component selected from a group comprising organic phosphors, inorganic yellow-green phosphors, and reddish inorganic phosphors.
The inorganic yellow-green phosphors may be selected from a group comprising YAG and Luag SSONE, and the reddish inorganic phosphors may be selected form a group comprising ECAS101, ECAS102, and BSSNe.
It is noted that the invention relates to all possible combinations of features recited in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
This and other aspects of the present invention will now be described in more detail, with reference to the appended schematic drawings showing embodiment(s) of the invention. In the drawings Fig. 1 shows a diagram of a light emitting device according to the invention; Fig. 2 shows a section of an embodiment of a light emitting unit; and
Fig. 3 shows a section of a different embodiment of a light emitting unit.
DETAILED DESCRIPTION
Fig. 1 shows a light emitting device comprising a light emitting unit 1 with a lighting vessel 3 having a bottom 5 and a transparent or translucent top wall 7. At the bottom 5 a plurality of light emitting diodes (LEDs) 9 are provided, the LEDs 9 having respective light emitting parts 11 facing the top wall 7. The lighting vessel 3 has a liquid inlet 13 and a liquid outlet 15. The light emitting device further comprises a heat exchanger 17 with a heat transfer surface 19 and a fan 21; a pump 23; and a reservoir tank embodied as a hydrophore 25.
Conduits 27 connect the above elements of the light emitting device to provide a circuit. Thus a first conduit 27a connects the liquid outlet 15 of the lighting vessel 3 and the heat exchanger 17, a second conduit 27b connects the heat exchanger 17 and the hydrophore 25, a third conduit 27c connects the hydrophore 25 and the pump 23, and finally a forth conduit 27d connects the pump 23 and the liquid inlet 13 of the lighting vessel 3.
The circuit thus provided by the lighting vessel 3, the heat exchanger 17, the hydrophore 25 and the pump 23 is filled with a liquid material 29, such an oil material, having particles of a phosphor material suspended therein as indicated by dots 31 in the lighting vessel 3.
In the embodiment illustrated in Fig. 2 the light emitting parts 11 of the LEDs 9 are in physical contact with the liquid material 29 in the lighting vessel 3. Thereby the light emitting parts 11 of the LEDs 9 are in heat conductive connection with the liquid material 29, which thus provides for cooling the LEDs 9.
In the embodiment illustrated in Fig. 3 a thin layer 33 of solid material or sheet, such as a silicone material, is isolating the LED's 9 from physical contact with the liquid material 29. In this embodiment the light emitting parts 11 of the LEDs 9 are in heat conductive connection with the liquid material 29, the layer 33 of solid material conducting heat from the LED's 9 to the liquid material 29, which thereby provides for cooling the LED's 9. The layer 33 of e.g. silicone material facilitates the provision of a sealed, especially moisture proof sealed lighting vessel 3 (apart from the liquid inlet and liquid outlet), which is beneficial if the phosphor material used is degradable by moisture.
The LEDs 9 may e.g. be of InGaN-type providing light of Royal Blue color. The liquid material 29 may be chosen from a group comprising oils, paraffin, and chlorinated paraffin. When paraffin or chlorinated paraffin is used a binder may be added to prevent the paraffin or chlorinated paraffin from separating. Such measure is per se known in the art. The liquid material should be liquid at the surrounding temperature where the light emitting device is intended to be used.
A number of different phosphors are known in the art and the phosphor material may e.g. be chosen from group comprising organic phosphors, inorganic yellow- green phosphors, i.e. phosphors emitting light in the yellow-green range, such as e.g. YAG and Luag SSONE, and reddish inorganic phosphors, i.e. phosphors emitting reddish light, such as e.g. ECAS101, ECAS102, and BSSNe. The actual phosphor to be chosen may depend on the actual type of LEDs used to provide for the light emitting unit to emit light of an intended color.
The size distribution of the particles of phosphor material may vary from microscopic particles that will give the respective liquid material a uniform diffuse glove when illuminated by the LED's, to macroscopic particles that will be individually visible. Microscopic particles may have sizes ranging from nano-scale to e.g. 100 μιη. Macroscopic individually visible particles may provide for inspection of whether the liquid material is flowing through the lighting vessel 3.
The liquid material 29 and the phosphor material 31 may be chosen to have similar densities to provide for the particles of phosphor material 31 to float in the liquid material 29. However the circulating movement of the liquid material 29 will provide for stirring up the particles of phosphor material 31 facilitating their suspension in the liquid material 29.
The hydrophore 25 provides for maintaining an overpressure in the circuit which e.g. is beneficial when the embodiment shown in Fig. 3 of the lighting unit 1 is used, since the overpressure will ensure contact between the sheet or layer 33 and the light emitting parts 11 of the LEDs 9 thereby providing for good transfer of heat from the LEDs 9 to the layer 33 from where the heat is further transferred to the liquid material 29.
In use the LEDs 9 emit light towards the top wall 7 through the liquid material 29 and the particles of phosphor material 31 convert the light or at least a part thereof, before it is transmitted through the top wall 7. Thereby the liquid material 29 with the particles of phosphor material 31 suspended therein acts as a volume diffuser providing for light mixing. The pump 23 circulates the liquid material 29 from the lighting vessel 3 to the heat exchanger 17 for the liquid material 29 to pass the heat transfer surface 19 which is cooled by surrounding air driven by the fan 21. The liquid material 29 thus cooled is then circulated from the heat exchanger 17 through the hydrophore 25 and the pump 23 back to the lighting vessel 3.
The invention provides freedom of design for a designer who is constructing a lighting implement incorporating a light emitting device since the light emitting unit may be quite small not needing to be attached to a solid heat sink and accordingly and may be placed in a confined space with reduced circulation of surrounding air to cool the light emitting unit while the other components of the light emitting device may be placed remote from the light emitting unit where space is available.
The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, a pressure less expansion vessel may be used as the reservoir tank instead of the hydrophore shown. Further the reservoir tank whether embodied as a hydrophore or not, may be attached to a blind end branch instead of having the liquid material flowing continuously through. Other types of LEDs, other types of liquid material and other types of phosphor material than the types specifically mentioned may be used.

Claims

CLAIMS:
1. A light emitting unit (1) comprising a lighting vessel (3) for containing a liquid material (29), and a light source comprising at least one light emitting diode (9), at least the light emitting part (11) of the light emitting diode (9) being positioned in the lighting vessel (3) to be in heat conductive connection with the liquid material (29), character- i z e d in that the lighting vessel (3) comprises a liquid inlet (13) and a liquid outlet (15).
2. A light emitting unit (1) according to claim 1, characterized in that the light emitting diode (9) is positioned to be in physical contact with the liquid material (29).
3. A light emitting unit (1) according to claim 1, characterized by a layer (33) of solid material isolating the light emitting diode (9) from physical contact with the liquid material (29), said layer (33) providing for conduction of heat between the light emitting diode (9) and the liquid material (29).
4. A light emitting unit (1) according to claim 3, characterized in that the solid material comprises a silicone material.
5. A light emitting device comprising a light emitting unit (1) according to any of claims 1 to 4, characterized in that the lighting vessel (3) is connected by the liquid outlet (15) and the liquid inlet (13) to a circuit comprising a heat transfer surface (19).
6. A light emitting device according to claim 5, characterized in that the heat transfer surface (19) is provided by a heat exchanger (17).
7. A light emitting device according to claim 5 or 6, characterized in that the circuit comprises a pump (23).
8. A light emitting device according to any of the claims 5 to 7, characterize d in that the circuit comprises an expansion vessel (25).
9. A light emitting device according to claim 8, characterized in that the expansion vessel is provided by a hydrophore (25).
10. A light emitting device according to any of the claims 5 to 9, characterize d in that the circuit is moisture proof sealed.
11. A light emitting device according to any of the claims 5 to 10, characterize d in that the circuit including the lighting vessel (3) contains a liquid material (29).
12. A light emitting device according to claim 11, characterized in that the liquid material (29) is selected from a group comprising oils, paraffin, and chlorinated paraffin.
13. A light emitting device according to claim 11 or 12, characterized in that particles of a phosphor material (31) are suspended in the liquid material (29).
14. A light emitting device according to claim 13, characterized in that the particles of phosphor material (31) comprise microscopic particles.
15. A light emitting device according to claim 13 or 14, characterized in that the phosphor material (31) comprises at least one phosphor component selected from a group comprising organic phosphors, inorganic yellow-green phosphors, and reddish inorganic phosphors.
PCT/IB2013/051909 2012-03-15 2013-03-11 An led device comprising a cooling liquid with suspended phosphor particles WO2013136250A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201261611152P 2012-03-15 2012-03-15
US61/611,152 2012-03-15

Publications (1)

Publication Number Publication Date
WO2013136250A1 true WO2013136250A1 (en) 2013-09-19

Family

ID=48227359

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2013/051909 WO2013136250A1 (en) 2012-03-15 2013-03-11 An led device comprising a cooling liquid with suspended phosphor particles

Country Status (1)

Country Link
WO (1) WO2013136250A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105114919A (en) * 2015-08-11 2015-12-02 电子科技大学 Heat dissipating device adopting paraffin and water cooling
CN105351901A (en) * 2015-12-12 2016-02-24 重庆信德电子有限公司 Water circulation type heat dissipation device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030052584A1 (en) * 2001-09-17 2003-03-20 Nobuyuki Matsui Lighting apparatus with enhanced capability of removing heat
EP1843402A1 (en) * 2006-04-04 2007-10-10 Noctron Holding S.A. Semiconductor illuminant and illumination panel with such system
JP2008004689A (en) 2006-06-21 2008-01-10 Noda Screen:Kk Light-emitting diode package
DE202009007426U1 (en) * 2009-05-25 2010-10-14 Zumtobel Lighting Gmbh Arrangement for emitting light with luminous elements
US20110255268A1 (en) * 2011-03-01 2011-10-20 Switch Bulb Company, Inc. Liquid displacer in led bulbs

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030052584A1 (en) * 2001-09-17 2003-03-20 Nobuyuki Matsui Lighting apparatus with enhanced capability of removing heat
EP1843402A1 (en) * 2006-04-04 2007-10-10 Noctron Holding S.A. Semiconductor illuminant and illumination panel with such system
JP2008004689A (en) 2006-06-21 2008-01-10 Noda Screen:Kk Light-emitting diode package
DE202009007426U1 (en) * 2009-05-25 2010-10-14 Zumtobel Lighting Gmbh Arrangement for emitting light with luminous elements
US20110255268A1 (en) * 2011-03-01 2011-10-20 Switch Bulb Company, Inc. Liquid displacer in led bulbs

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105114919A (en) * 2015-08-11 2015-12-02 电子科技大学 Heat dissipating device adopting paraffin and water cooling
CN105114919B (en) * 2015-08-11 2018-02-13 电子科技大学 It is a kind of using paraffin and the heat abstractor of water cooling
CN105351901A (en) * 2015-12-12 2016-02-24 重庆信德电子有限公司 Water circulation type heat dissipation device
CN105351901B (en) * 2015-12-12 2018-10-16 重庆信德电子有限公司 Circulating water type radiator

Similar Documents

Publication Publication Date Title
JP2001036148A (en) Light source
CN103052838B (en) LED bulb
CN102782404B (en) Lighting device with heat dissipation elements
KR200438525Y1 (en) Cooling device for led light source using non-conductive liquid
US8591069B2 (en) LED light bulb with controlled color distribution using quantum dots
JP2008027910A (en) High power led lamp with heat dissipation exhancement
CN101896766A (en) Diffuser for LED light sources
CA2826210A1 (en) Omni-directional channeling of liquids for passive convection in led bulbs
CN102330962A (en) Lighting method and device of LED (light-emitting diode)
EP3745025A1 (en) Light emitting diode cooling systems and methods
US20080295522A1 (en) Thermo-energy-management of solid-state devices
CN101769521A (en) Heat dissipation device for light-emitting device and light-emitting device thereof
US11821616B2 (en) Systems and methods for a coolant chamber
WO2013136250A1 (en) An led device comprising a cooling liquid with suspended phosphor particles
CN201589926U (en) Heat radiation structure used for miniature projection
JP3112794U (en) Radiator for light-emitting diode lamp
CN208805674U (en) A kind of exposure machine lamp box with radiator
US11946628B2 (en) Light emitting diode cooling systems and methods
US9239160B1 (en) Cooled LED lighting apparatus
US11383181B2 (en) Systems and method for a coolant chamber
KR101321581B1 (en) Light emitting diode lamp
CN213664817U (en) Thermal conversion equipment with diode heat transfer function
KR20160129195A (en) Led lamp with heat radiation mechanism for convection circulation
KR101524127B1 (en) Heat discharging method and apparatus
US20140265811A1 (en) Led light bulb with a phosphor structure in an index-matched liquid

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13719622

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13719622

Country of ref document: EP

Kind code of ref document: A1