Thermoelectric cooling and/or moderation of transient thermal load using phase change material

Abstract

Techniques described and illustrated herein can permit high luminous flux and/or longer lifetimes for a class of photoemissive device configurations and/or uses that generate intense highly localized, but transient heat flux. For example, certain Light Emitting Diode (LED) applications, e.g., for flash illumination, certain solid state laser configurations and other similar configurations and uses may benefit from the developed techniques. In particular, it has been discovered that by locating an amount of appropriate phase change material in close thermal proximity to such a photoemissive device, substantial generated heat fluxes may be “absorbed” into a phase transition of the phase change material. In some configurations, a thermoelectric is employed in conjunction with the phase change material. For example, the thermoelectric may at least partially define a heat transfer path from the photoemissive device to the phase change material. Similar configurations may be employed for photosensitive devices. In such configurations, the phase change material may effectively clamp one side (typically the hot side) of the thermoelectric as heat transferred across the thermoelectric is absorbed into the transition of at least some of the phase change material from a first state thereof to a second state. The thermoelectric may be transiently operated in substantial synchrony with operation of the photoemissive or photosensitive device to provide extremely high density spot cooling when and where desired.

1 . An apparatus comprising: 
 an optoelectronic device;    a thermoelectric cooler thermally coupled to the optoelectronic device to at least partially define a heat transfer path from the optoelectronic device; and    a phase change material disposed in the heat transfer path to undergo a transition from a first phase to a second phase thereof and thereby absorb heat transferred by the heat transfer path.    
   
   
       2 . The apparatus of  claim 1 , 
 wherein the optoelectronic device is transiently operable and wherein the phase change material undergoing the transition absorbs a substantial portion of heat evolved by the optoelectronic device coincident with such transient operation.    
   
   
       3 . The apparatus of  claim 2 , 
 wherein the thermoelectric cooler is operable to transfer to the phase change material the heat evolved by the optoelectronic device.    
   
   
       4 . The apparatus of  claim 2 , 
 wherein the thermoelectric cooler is operable to transfer heat from the phase change material.    
   
   
       5 . The apparatus of  claim 1 , 
 wherein the thermoelectric cooler is operable to transfer heat from the phase change material and thereby cause the phase change material to transition from the second phase thereof to the first phase thereof.    
   
   
       6 . The apparatus of  claim 5 , 
 wherein the second phase to first phase transition is performed prior to or in anticipation of a transient operation of the optoelectronic device.    
   
   
       7 . The apparatus of  claim 5 , 
 wherein the second phase to first phase transition is performed after a transient operation of the optoelectronic device, thereby reversing a prior first phase to second phase transition of the phase change material, which absorbed heat transferred across the thermoelectric cooler coincident with such transient operation.    
   
   
       8 . The apparatus of  claim 1 , 
 wherein the thermoelectric cooler is transiently operable and wherein the transition of the phase change material absorbs a substantial portion of heat transferred across the thermoelectric cooler coincident with such transient operation.    
   
   
       9 . The apparatus of  claim 8 , 
 wherein the optoelectronic device is a sensor device, and    wherein the thermoelectric cooler is transiently operable to cool the optoelectronic device below an ambient temperature.    
   
   
       10 . The apparatus of  claim 9 , 
 wherein the sensor device includes one or more of: 
 a charge coupled device (CCD); and  
 a complementary metal oxide semiconductor (CMOS) array.  
   
   
   
       11 . The apparatus of  claim 8 , 
 wherein the optoelectronic device is an emissive device, and    wherein the heat transferred across the thermoelectric cooler includes that evolved by operation of the emissive device.    
   
   
       12 . The apparatus of  claim 9 , 
 wherein the emissive device includes one or more of: 
 a light emitting diode (LED); and  
 a semiconductor laser.  
   
   
   
       13 . The apparatus of  claim 8 , 
 wherein the optoelectronic device is transiently operable is substantial synchrony with the thermoelectric cooler.    
   
   
       14 . The apparatus of  claim 1 , 
 wherein the thermoelectric cooler is operable to transfer heat from the phase change material and thereby reverse the first to second phase transition.    
   
   
       15 . The apparatus of  claim 1 , 
 wherein the thermoelectric cooler is thermally coupled between the optoelectronic device and the phase change material.    
   
   
       16 . The apparatus of  claim 15 , 
 wherein temperature of a phase change material facing side of the thermoelectric cooler is substantially clamped based on a latent heat of transformation for the phase change material.    
   
   
       17 . The apparatus of  claim 16 , 
 wherein the clamped temperature corresponds to a first to second phase transition temperature for the phase change material.    
   
   
       18 . The apparatus of  claim 15 , 
 wherein the optoelectronic device evolves, during operation, a substantial portion of the heat absorbed in the first to second phase transition.    
   
   
       19 . The apparatus of  claim 15 , 
 wherein the thermoelectric cooler transfers, during operation, a substantial portion of the heat absorbed in the first to second phase transition.    
   
   
       20 . The apparatus of  claim 19 , 
 wherein the optoelectronic device evolves, during operation, a substantial portion of the heat transferred by the thermoelectric cooler and absorbed in the first to second phase transition.    
   
   
       21 . The apparatus of  claim 19 , 
 wherein the optoelectronic device is cooled, by operation of the thermoelectric cooler, below an ambient temperature.    
   
   
       22 . The apparatus of  claim 1 , 
 wherein the phase change material is thermally coupled between the optoelectronic device and the thermoelectric cooler.    
   
   
       23 . The apparatus of  claim 22 , 
 wherein, during a heat-evolving transient operation of the optoelectronic device, temperature of the optoelectronic device is substantially moderated based on a latent heat of transformation for the phase change material.    
   
   
       24 . The apparatus of  claim 22 , 
 wherein the thermoelectric cooler is operable to transfer heat from the phase change material and thereby reverse the first to second phase transition.    
   
   
       25 . The apparatus of  claim 22 , 
 wherein the thermoelectric cooler is operable to transfer heat from the phase change material and thereby transition a substantial portion of the phase change material from the second phase to the first phase thereof prior to or in anticipation of a transient operation of the optoelectronic device.    
   
   
       26 . The apparatus of  claim 1 , 
 wherein at ambient conditions, the phase change material is in the first phase thereof.    
   
   
       27 . The apparatus of  claim 1 , 
 wherein at ambient conditions, the phase change material is in the second phase thereof.    
   
   
       28 . The apparatus of  claim 1 , 
 wherein the first phase is a solid phase, and    wherein the second phase is a liquid phase.    
   
   
       29 . The apparatus of  claim 1 , 
 wherein the first phase is a liquid phase, and    wherein the second phase is a gas phase.    
   
   
       30 . The apparatus of  claim 1 , 
 wherein the first phase is a solid phase, and    wherein the second phase is a gas phase.    
   
   
       31 . The apparatus of  claim 1 , 
 wherein the first and second phases are both solid state phases.    
   
   
       32 . The apparatus of  claim 1 , further comprising: 
 confinement for the phase change material when in a non-solid state.    
   
   
       33 . The apparatus of  claim 32 , 
 wherein the confinement encapsulates the phase change material.    
   
   
       34 . The apparatus of  claim 32 , 
 wherein the confinement operates to inhibit flow of the phase change material when in a liquid state in part by surface tension of the liquid state phase change material.    
   
   
       35 . An apparatus comprising: 
 an optoelectronic device; and    a phase change material thermally proximate to the optoelectronic device to undergo a transition from a first phase to a second phase thereof and thereby absorb at least a substantial portion of heat evolved by transient operation of the optoelectronic device.    
   
   
       36 . The apparatus of  claim 35 , further comprising: 
 a thermoelectric cooler operable to transfer heat from the phase change material and thereby reverse the first to second phase transition    
   
   
       37 . The apparatus of  claim 35 , further comprising: 
 a thermoelectric cooler operable to transfer heat from the phase change material and thereby transition a substantial portion of the phase change material from the second phase to the first phase thereof prior to or in anticipation of the transient operation of the optoelectronic device    
   
   
       38 . A method of moderating temperature of an optoelectronic system, the method comprising: 
 transiently operating an optoelectronic device that evolves heat; and    absorbing at least a substantial portion of the heat evolved by transient operation of the optoelectronic device in a phase change material thermally proximate to the optoelectronic device, the phase change material undergoing a transition from a first phase to a second phase thereof.    
   
   
       39 . The method of  claim 38 , further comprising: 
 transferring heat from the phase change material and thereby reversing the first to second phase transition.    
   
   
       40 . A method of cooling an optoelectronic device, the method comprising: 
 transferring heat from the optoelectronic device along a heat transfer path that includes a thermoelectric cooler; and    absorbing, in a phase change material undergoing a transition from a first phase to a second phase thereof, at least a substantial portion of the heat transferred in the heat transfer path.    
   
   
       41 . The method of  claim 40 , further comprising: 
 transiently operating the optoelectronic device and thereby evolving a substantial portion of the heat transferred and absorbed in the phase change material.    
   
   
       42 . The method of  claim 41 , further comprising: 
 transferring to the phase change material, using the thermoelectric cooler, the heat evolved by the optoelectronic device.    
   
   
       43 . The method of  claim 41 , further comprising: 
 transferring heat from the phase change material, using the thermoelectric cooler.    
   
   
       44 . The method of  claim 40 , further comprising: 
 transiently operating the thermoelectric cooler to transfer thereacross a substantial portion of the heat absorbed in the phase change material.    
   
   
       45 . The method of  claim 44 , further comprising: 
 transiently operating the optoelectronic device in substantial synchrony with the thermoelectric cooler.    
   
   
       46 . The method of  claim 40 , further comprising: 
 transferring heat from the phase change material, using the thermoelectric cooler, thereby reverse the first to second phase transition.