Patent Publication Number: US-2010118902-A1

Title: Unitized cooling module for laser diode array

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cooling module for a laser diode array, in particular, to a unitized cooling module for a laser diode array. 
     2. Description of the Related Art 
     A conventional laser diode array mainly adopts an aluminum alloy heatsink module for heat dissipation. However, different heatsink module designs are provided to match the powers of various high power laser diode array. 
       FIG. 1  is a schematic view of a conventional cooling module. The conventional cooling module  1  includes an aluminum alloy substrate  11  with a plurality of heatsink fins  111  and a fan  12 . In the conventional art, a plurality of high power laser diodes  13  is configured on the aluminum alloy substrate  11 . The heat produced by the high power laser diodes  13  is conducted to the aluminum alloy substrate  11 , and the fan  12  drives air through the heatsink fins  111  so as to dissipate the heat. 
     The conventional cooling module  1  is only applicable to a low power laser system, and is inapplicable to laser diodes of a high output power or to some special fiber connectors (as the service life of the module is easily shortened). In the conventional art, the heatsink fins  111  are made of an aluminum alloy material. After the laser diodes  13  are powered on, the temperature thereof suddenly rises due to the high current, and thus, the light-emitting quality is unstable. 
       FIG. 2  is a schematic view of a conventional cooling module for laser diode array with high-density packaging. The conventional cooling module  2  is applied to solve the heat-dissipating problem of a high power laser system having a plurality of laser diodes. Conventionally, the plurality of laser diodes  21  is sintered in an array on one end (hot end) of a heat-dissipating base  22  by means of high-density packaging, and then the cooling module is designed according to the size of the heat-dissipating base  22 . The heat-dissipating base  22  has a cooling fluid disposed therein. The heat produced by the laser diodes  21  is first conducted to the cool fluid, then brought to the other end (cold end) of the heat-dissipating base  22  by the cooling fluid, and removed through an external cooling device. 
     However, the main disadvantage of the conventional high-density packaged cooling module  2  is that the structure thereof is not compact enough, and when the number or stacking manner of the laser diodes  21  is changed, the conventional high-density packaged cooling module  2  must be redesigned correspondingly. 
     Therefore, there is a need to provide a unitized cooling module to solve the above problem. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a unitized cooling module for a laser diode array. The module has at least one cooling unit. The cooling unit includes a main body and a heatsink element. The main body has an inlet main channel, an outlet main channel, an inlet subchannel, an outlet subchannel, and a chamber. The inlet subchannel connects the inlet main channel and the chamber, the outlet subchannel connects the outlet main channel and the chamber, and the chamber has an opening. The heatsink element has a first surface and a second surface opposite each other, the first surface seals the opening, and the second surface carries a laser diode. 
     The unitized cooling module for a laser diode array of the present invention is easily assembled, repaired, and expanded, and has the effect of pressing fit. Furthermore, the unitized cooling module for a laser diode array of the present invention can be arranged and designed according to the heat produced by the laser diode to effectively remove the heat from the laser diode, so as to control the temperature of the laser diode, so that the performance of the laser diode is ensured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a conventional cooling module; 
         FIG. 2  is a schematic view of a conventional cooling module for high-density packaged laser diode array; 
         FIG. 3  is a schematic view of a cooling module for a laser diode array according to a first embodiment of the present invention; 
         FIG. 4  is an exploded view of a cooling unit according to the first embodiment of the present invention; 
         FIG. 5  is a top view of the cooling unit according to the first embodiment of the present invention; 
         FIG. 6  is a schematic view of a cooling module for a laser diode array according to a second embodiment of the present invention; and 
         FIG. 7  is an exploded view of a cooling unit according to the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 3  is a schematic view of a cooling module for a laser diode array according to a first embodiment of the present invention,  FIG. 4  is an exploded view of a cooling unit according to the first embodiment of the present invention, and  FIG. 5  is a top view of the cooling unit according to the first embodiment of the present invention. As shown in  FIGS. 3 and 4 , the unitized cooling module for a laser diode array  3  according to the first embodiment of the present invention has a plurality of cooling units  4 , a cooling source  5 , a sensing device  6 , and a flow controller  7 . 
     In this embodiment, the cooling module of the present invention is a stacked cooling module for a laser diode array  3 , so as to solve the heat-dissipating problem of a high power laser system having a plurality of laser diodes  8 . Each cooling unit  4  is used to cool the corresponding laser diode  8  and keep the temperature of the laser diode  8  within a set range. 
     As shown in  FIGS. 3 to 5 , each cooling unit  4  includes a main body  41 , a heatsink element  42 , a first sealing element  43 , and at least one fixing element  44 . The main body  41  has an inlet main channel  411 , an outlet main channel  412 , an inlet subchannel  413 , an outlet subchannel  414 , a chamber  415 , and a disposing region  416 . The inlet subchannel  413  connects the inlet main channel  411  and the chamber  415 , the outlet subchannel  414  connects the outlet main channel  412  and the chamber  415 , and the chamber  415  has an opening  417 . The disposing region  416  surrounds the opening  417 . 
     The heatsink element  42  has a first surface  421  and a second surface  422  opposite each other, the first surface  421  seals the opening  417 , and the second surface  422  carries the laser diode  8 . In this embodiment, the heatsink element  42  includes a plurality of fins  423  disposed on the first surface  421 . The fins  423  are disposed in parallel on the first surface  421  along a first direction, and in this embodiment, the first direction is substantially perpendicular to the inlet main channel  411  or the outlet main channel  412 . The fins  423  expand the transfer area, and thus improve the heat transfer performance. 
     The first sealing element  43  is disposed between the disposing region  416  of the main body  41  and the heatsink element  42 . In this embodiment, the disposing region  416  is a circular depressed portion, and the shape of the first sealing element  43  matches that of the circular depressed portion. The fixing element  44  is used to fix the laser diode  8  and the heatsink element  42  on the main body  41 . 
     The coolant source  5  is connected to the inlet main channel  411 , and in this embodiment the coolant source  5  is a fluid (for example, water). The first sealing element  43  disposed between the disposing region  416  of the main body  41  and the heatsink element  42  is used to prevent the coolant source  5  from leaking. The sensing device  6  is used to measure the temperature of the laser diodes  8 . 
     In this embodiment, the flow controller  7  is disposed between the coolant source  5  and the inlet main channel  411 . The flow controller  7  controls the flow of the coolant source  5  according to the temperature of the laser diodes  8  measured by the sensing device  6 . 
     In this embodiment, the unitized cooling module for a laser diode array  3  further includes a plurality of second sealing elements  9  and a cover plate  10 . The cooling units  4  are connected by stacking. In particular, the is inlet main channel  411  and the outlet main channel  412  of each cooling unit  4  are correspondingly connected to the inlet main channel  411  and the outlet main channel  412  of the neighboring cooling unit  4 . The respective second sealing elements  9  are disposed between the respective neighboring cooling units  4 , to prevent the coolant source  5  from leaking. 
     The cover plate  10  seals the inlet main channel  411  and the outlet main channel  412  on one end of the cooling unit  4 , so that the coolant source  5  sequentially flows through the inlet main channel  411 , the inlet subchannel  413 , the chamber  415 , the outlet subchannel  414 , and the outlet main channel  412  (a cooling system may be formed with external devices such as a circulating pump, a coolant storage tank, and a heat exchanger), so as to successfully remove the heat conducted to the heatsink element  42  from each laser diode  8 . 
       FIG. 6  is a schematic view of a cooling module for a laser diode array according to a second embodiment of the present invention, and  FIG. 7  is an exploded view of a cooling unit according to the second embodiment of the present invention. As shown in  FIGS. 6 and 7 , the unitized cooling module for a laser diode array  50  according to the second embodiment of the present invention has a plurality of cooling units  60 , a coolant source  70 , a sensing device  80 , and a plurality of flow controllers  90 . Each cooling unit  60  includes a main body  61 , a heatsink element  62 , a first sealing element  63 , and at least one fixing element  64 . In the second embodiment, the main body  61  of each cooling unit  60  further includes an extension portion  611 , and a chamber  612  of the cooling unit  60  is disposed in the extension portion  611 . Each flow controller  90  is disposed between the chamber  612  and an inlet main channel  613  of each cooling unit  60  (or disposed between the chamber  612  and an outlet main channel  614  of the cooling unit  60 ). The flow controller  90  controls the flow of the coolant source  70  entering the chamber  612  according to the temperature of a laser  15  diode  100  measured by the sensing device  80 . Other components of the unitized cooling module for a laser diode array  50  of the second embodiment are the same as those of the unitized cooling module for a laser diode array  3  of the first embodiment, and the details will not be given herein again. 
     It should be noted that the unitized cooling module for a laser diode array  50  of the second embodiment may only include a flow controller, and the flow controller may be selectively disposed between the cooling source and the inlet main channel or the outlet main channel of the cooling unit. 
     In view of the above, the unitized cooling module for a laser diode array of the present invention is easily assembled, repaired, and expanded, and has the effect of pressing fit. Furthermore, the unitized cooling module for a laser diode array of the present invention can be arranged and designed according to the heat produced by a single laser diode or by a high power laser system with a plurality of laser diodes. A flow controller is employed to control the flow of the coolant source according to the temperature of the laser diode measured by the sensing device, so as to control the temperature of the laser diode, so that the performance of the laser diode is ensured. 
     While the embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention may not be limited to the particular forms as illustrated, and that all modifications that maintain the spirit and scope of the present invention are within the scope as defined in the appended claims.