Patent Publication Number: US-2023133955-A1

Title: Systems and methods for a heat sink

Description:
BACKGROUND INFORMATION 
     Field of the Disclosure 
     Examples of the present disclosure are related to systems and methods for a heat sink. More particularly, embodiments disclose a light fixture with a heat sink configured to dissipate heat caused by the light fixture, wherein the heat sink includes vents that extend orthogonal to an extruded axis of fins of the heat sink. 
     Background 
     Greenhouses are buildings or complexes in which plants are grown. For various reasons including price, it is typically ideal for greenhouses to operate with as much natural sunlight as possible. To supplement natural light from the sun, high powered lights are used within greenhouses when the sun or other natural light does not provide enough light for optimal plant growth. 
     However, the operation of the high-powered lights is more costly than utilizing free sunlight. More so, conventional high-powered lights are larger in size, which blocks the incoming free sunlight. Furthermore, the blocking of the incoming sunlight causes shading on the plants within the greenhouse, which negatively impacts the grower&#39;s productivity. 
     Although light emitting diodes (LEDs) are more efficient than traditional high-powered lights, their manufacturing costs are higher. Additionally, the LEDs cause excessive shading based on requiring larger fixtures to dissipate heat. To circumvent the large fixtures required to dissipate the heat, some manufacturers have attempted to build smaller LED fixtures that use active cooling fans. However, in greenhouse environments, active cooling fans quickly clog with dirt, bugs, etc. This causes the LED fixtures with active cooling fans to quickly become inoperable. 
     Conventional LED fixtures that do not include active cooling fans use traditional linear heat sinks. Heat generated through conventional LED fixtures may dissipate based on convection, conduction or radiation. However, due to LED fixtures being suspended, there is minimal heat dissipation via conduction. Radiation is a function of the fixture temperature and may be significant, and convection is the primary method to dissipate heat. In applications, air particles remove heat from the fixture through air movement. For longer heat sinks, air movement within the middle of the fixtures is minimal. This severely limits the amount of power conventional LED fixtures can consume because additional power consumption leads to more heat. 
     Accordingly, needs exist for more effective and efficient systems and methods for a heat sink that includes vents that extend orthogonal to an extruded axis of fins of the heat sink, wherein the vents allow direct and cross flow air movement. 
     SUMMARY 
     Embodiments disclosed herein describe systems and methods for heat sinks within light fixtures. In embodiments, a heat sink may be a passive system that continually and passively creates direct flow and cross-flow thermal management system dissipating large amounts of heat in a slim light fixture. Embodiments may utilize a series of extruded and exposed fins that increase the surface area of the heat sink creating additional air flow. As hotter air rises within the system, cooler is drawn into the heatsink. The fins may have exposed sides, partially exposed lower surfaces, and exposed upper surfaces. The exposed and unobstructed surfaces may allow cooler air to be drawn towards the central axis of the light fixture above the light source, and then flow upward. This process may cool the fins by passively drawing cooler air within a body of the light fixture, wherein the drawn air is configured to flow between pairs of fins. Additionally, the spacing between the fins may be wide enough to allow for air to freely enter the heatsink. 
     Specifically, embodiments may include light sources, thermal grease, a base (such as Metal Core PCB, thermal PCB or metal backed PCB), and a plurality of the extruded fins. 
     The light sources may be an artificial light source that is configured to stimulate plant growth by emitting light. For example, the light source may be LEDs. The light sources may be utilized to create light or supplement natural light to the area of interest. The light sources may provide a light spectrum that is similar to the sun, or provide a spectrum that is tailored to the needs of particular pants being cultivated. In embodiments, responsive to generating light the light sources may generate heat. One skilled in the art may appreciate that in alternative embodiments the light sources may be replaced with any device that generates heat. 
     The thermal grease may be a substance or device that is configured to promote thermal conduction between the plurality of fins and the light sources or heat generating sources. In embodiments, the thermal grease may be configured to be directly adjacent to and between the base and the light sources. In embodiments, one skilled in the art may appreciate that alternative embodiments may include thermal glue, thermal pads, or any other device that increases thermal conduction between elements. 
     The base may be metal core PCB or any other device that has a metal material to spread heat generated by the light sources. In embodiments the base may be formed of unextruded parts of an aluminum block. The base may be configured to divert heat away from the light sources and circuitry and towards the heat sink formed of the plurality of fins. In embodiments, the plurality of fins may be directly mounted to the base. 
     In embodiments, the base may include a plurality of vents, wherein the vents extend in a directional orthogonal to extruded axis of the plurality of fins. In embodiments, the vents may be machined into the base. For example, the extruded axis may extend along the longitudinal (long) axis of the heat sink, and the vents may extend along a lateral (short) of the heat sink. In embodiments, a width of the vents may correspond to a pitch of or distance between adjacent fins. Additionally, a spacing between adjacent vents may correspond to a length of the lateral axis the heat sink or a distance between a face of the outermost fin and a face of the innermost fin. This specific geometry may effectively and efficiently allow for cross flow through the unvented area of the plurality of fins and direct flow across the fins through the vented areas. 
     The plurality of fins may be formed by extruding the unitary block of metal, such as an aluminum block, which is the same block that forms the base. The plurality of fins may be formed via linear extrusions that extend along the longitudinal axis of the heat sink to create long fins. In other words, the extrusions may extend through the longitudinal axis of the block, such that the extrusions are longer than a width of the plurality of fins. Additionally, while the fins are being extruded, the base may be simultaneously formed below the fins. The base and fins may be created by passing the unitary block of metal through a die, wherein the base portions of the die does not include fin extrusions. To this end, the plurality of fins and the base may be formed from the unitary block of metal. 
     While operating, the light source may create heated air. As the air is being heated, the heated air may move around the edges of the outer fins. Additionally, the heats air may move towards the vents and directly through a lower surface of the fins through the vents. The heated air may then move vertically between pairs of fins from the lower surface of the fins towards an upper surface of the fins. The heated air may move directly in a vertical flow through the vents to dissipate directly into the atmosphere. The heated air may also move between pairs of fins towards a front of the heat sink and towards a rear of the heat sink. This may more evenly move air through the heat sink by allowing simultaneously cross flow of air through a plurality of pairs of vents along the longitudinal axis of the heat sink and direct air flow through the plurality of pairs of vents. 
     Accordingly, by positioning the vents across the width of the heat sink, a portion of the heated air is only required to move vertically through the fins, while also allowing air to move towards the front and back of the heat sink over the unvented portion of the base, which may more uniformly disturbed the generated heat over the heat sink. 
     These, and other, aspects of the invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. The following description, while indicating various embodiments of the invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many substitutions, modifications, additions or rearrangements may be made within the scope of the invention, and the invention includes all such substitutions, modifications, additions or rearrangements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG.  1    depicts a heat sink system, according to an embodiment. 
         FIG.  2    depicts a top view of a heat sink, according to an embodiment. 
         FIG.  3    depicts an air flow diagram through and around a heat sink, according to an embodiment. 
         FIG.  4    depicts a bottom view of a heat sink, according to an embodiment. 
         FIG.  5    depicts a bottom perspective view of a heat sink, according to an embodiment. 
         FIG.  6    depicts a front view of a heat sink, according to an embodiment. 
         FIG.  7    illustrates a method for dissipating heat into an environment, according to an embodiment. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present disclosure. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present disclosure. 
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present embodiments. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present embodiments. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present embodiments. 
     Embodiments disclosed herein describe systems and methods for heat sinks within light fixtures. In embodiments, the heat sink may be a passive system that creates a cross-flow and direct thermal management system configured to dissipate large amounts of heat in a slim light fixture. 
       FIG.  1    depicts a heat sink system  100 , according to an embodiment. Heat sink system  100  may include light sources  110 , thermal grease  120 , base  130 , fins  140 , and rails  150 . 
     Light sources  110  may be any device that is configured to generate heat into the atmosphere, wherein it is desirable to dissipate the heat into the atmosphere. For example, light sources  110  may be an artificial light source that is configured to stimulate plant growth by emitting light. In a specific embodiment, light sources  110  may be LEDs. Light sources  110  may be utilized to create light or supplement natural light to the area of interest. Light sources  110  may provide a light spectrum that is similar to the sun, or provide a spectrum that is tailored to the needs of particular pants being cultivated. 
     Thermal grease  120  may be a substance, device, etc. that is configured to promote thermal conduction between the plurality of fins  140  and the light sources  110  or heat generating sources. Thermal grease  120  may be configured to be directly adjacent to and between the base  130  and the light sources  110 . In embodiments, one skilled in the art may appreciate that alternative embodiments may include thermal glue, thermal pads, or any other device that increases thermal conduction between elements. Specifically, thermal grease  120  may be configured to assist fins  140  to uniformly dissipate heat into the atmosphere by promoting the thermal conduction between fins  140  and light sources  110 . 
     Base  130  may be metal core PCB or any other device that has a metal material to spread heat generated by light sources  110 . Base  130  may be configured to divert heat away from the light sources  110  and circuitry and towards the heat sink formed of the plurality of fins  140 . In embodiments, base  130  and fins  140  may be formed from a same block of aluminum, and base  130  is formed by not extruding the aluminum at desired locations. Alternatively, the plurality of fins  140  may be directly mounted to base  130 . 
     Base  130  may include a plurality of vents  132  or openings that extend across an entirety of a lower surface of heat sink  100  to expose lower surfaces of each of the plurality of fins  140  to an area below heat sink  100 . Vents  132  may be machined portions of base  130  that extend in a directional orthogonal to extruded axis of the plurality of fins  140 . For example, the extruded axis may extend along the longitudinal (long) axis of the heat sink  100 , and the vents may extend along a lateral (short) of the heat sink  100 . In other words, the width of vents  132  may be longer than a length of vents  132 , which may allow a lower surface of each of the plurality of fins  140  to be unobstructed and not covered by base  130  over desired intervals. In embodiments, a length of the vents  132  may correspond to a pitch of or distance between adjacent fins  140  along the lateral axis. Additionally, a spacing between adjacent vents  132  may correspond to a length of the lateral axis the heat sink  100  or a distance between a face of the outermost fin  140  and a face of the innermost fin  140 . This specific geometry may effectively and efficiently allow for cross flow through the unvented area of the plurality of fins  140  and direct flow across the fins through the vented areas. Specifically, the air may flow axially in multiple directions along the longitudinal axis between each adjacent pair of vents  132 . This may enable each cross section of heat sink  100  along the longitudinal axis to have a more symmetrical thermal heat profile than unvented systems or systems utilizing fins  140  extruded along a later axis. 
     The plurality of fins  140  may be formed by extruding a unitary block of metal, such as an aluminum block. The extrusions may extend through the longitudinal axis of the block, such that the extrusions are longer than a width of the plurality of fins  140 . Additionally, while the fins  140  are being extruded, the base  130  may simultaneously formed below the fins. The base  130  and fins  140  may be created by passing the unitary block of metal through a die, wherein the base  130  portions of the die does not include fin  140  extrusions. To this end, the plurality of fins  140  and the base  130  may be formed from the unitary block of metal. The plurality of fins  140  may extend along an entirety, and in parallel to, the longitudinal axis of heat sink  100 . The plurality of fins  140  may be evenly spaced apart along the lateral axis of the heat sink  100 . Each of the plurality of fins  140  may have the same height, or the plurality of fins  140  may have different heights. The inner faces and outer faces of each of the fins  140  may include etching, which may increase a surface area of the plurality of fins  140 . In embodiments, a lower surface of each of the plurality of fins  140  may be obstructed by base  130  and unobstructed by vents  132 . This may allow portions of the lower surfaces of the each of the plurality of fins  140  to be obstructed and unobstructed at desired intervals. 
     Furthermore, the cross flow of heated air may cause portions of air traveling through a first vent to flow towards first end  102  of heat sink  100 , and cause other portions of air traveling through the first vent to flow towards second end  104  of heat sink. When the air is traveling towards the first end  102  or second end  104  the heated air may be confined between adjacent fins  140  over the unvented portion of base  130  until the heated air travels upward beyond an upper surface of fins  140 , wherein the axial moving air may allow the fins  140  to be more uniformly heated along the longitudinal axis of heat sink  100 . In further embodiments, the cross flow of air between subsequent vents  132  may impact the flow of air between each of the pair of fins  140 . 
     Rails  150  may be removably coupled to base  130  via coupling mechanisms, such as screws  154 , fasteners, etc. Rails  120  may extend from first end  102  to second end  104  of heat sink  118 . Rails  150  may be configured to add rigidity and support for fins  140 . Rails  150  may include a plurality of tabs  152  that extend towards a central axis of heat sink  100 , and may be configured to be positioned directly over light sources  110  between the circuitry of the light source  110 . When fasteners  154  are through tabs  152  and include corresponding threads on light sources  110 , rails  150  may apply sufficient force against light source to allow sufficient heat transfer between the heat created by light sources and fins  140 . Tabs  152  may be spaced along the longitudinal axis of heat sink  100  to more distribute the forces created by rails  150  against light sources  110 . In embodiments, responsive to fasteners  154  being decoupled from light sources  110 , light sources  110  may be replaced. 
       FIG.  2    depicts a top view of heat sink  100 , according to an embodiment. Elements depicted in  FIG.  2    may be described above, and for the sake of brevity a further description of these elements may be omitted. 
     As depicted in  FIG.  2   , vents  132  may be openings within base  130  that extend across the lateral axis of heat sink  100 . In operation, as air is being heated by the light sources, the heated air may move over edges  210  of the fins  140 . 
     Additionally, as the air is being heated, the heated air may directly pass upward through a lower surface of the fins  140  through the vents  132 . Accordingly, by positioning the vents  132  across the width of the heat sink, a portion of the heated air is only required to move vertically through the fins  140 . Additionally, the heated air may pass around the edges  220  of vents  132  to enable cross flow over the unvented portion of heat sink  100 . This may enable simultaneous cross flow over the unvented portion of the heat sink  100  and direct air flow through the vented portion of the heat sink  100 , which may more uniformly disturbed the generated heat over the heat sink  100 . 
       FIG.  3    depicts an air flow diagram  300  through and around heat sink  100 , according to an embodiment. Elements depicted in  FIG.  3    may be described above, and for the sake of brevity a further description of these elements is omitted. 
     As depicted in  FIG.  3    as cool air rises through heat sink, the air may get heated and transferred out of the system. Vents  132  may allow for cross-flow  320  through each section of heat sink  100  between vents  132 , while also allowing direct flow  310  through vents  132 . More so, allowing for direct flow  310  may allow for air to quickly and efficiently leave the system. 
       FIG.  4    depicts a bottom view of heat sink  100 , according to an embodiment. Elements depicted in  FIG.  4    may be described above, and for the sake of brevity a further description of these elements may be omitted. 
     As depicted in  FIG.  4   , light sources  110  may be positioned between adjacent vents  132 . This should allow the heat generated by light sources  110  to flow directly between fins  140  from a location below fins  140 , allowing the hot air to rise directly through fins  140 . The heated air that does not directly flow into vents  132  may flow around the edges  210  of heat sink  100 . 
       FIG.  5    depicts a bottom perspective view of heat sink  100 , according to an embodiment. Elements depicted in  FIG.  5    may be described above, and for the sake of brevity a further description of these elements may be omitted. 
       FIG.  6    depicts a front view of heat sink  100 , according to an embodiment. Elements depicted in  FIG.  6    may be described above, and for the sake of brevity a further description of these elements may be omitted. 
     As depicted in  FIG.  6   , light sources  110  may be directly positioned on base  130 , wherein base  130  may be formed simultaneously from a non-extruded portion of a block of metal and fins  140  may be formed by extruding the block of metal. This may allow base  130  and fins  140  to be a unitary element. 
       FIG.  7    illustrates a method  700  for dissipating heat into an environment, according to an embodiment. The operations of method  700  presented below are intended to be illustrative. In some embodiments, method  700  may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method  400  are illustrated in  FIG.  7    and described below is not intended to be limiting. 
     At operation  710 , a light fixture within a greenhouse may be turned on. 
     At operation  720 , responsive to the light fixture being turned on, the light fixture may heat the air in the environment surrounding the light fixture. 
     At operation  730 , when the air is heated, due to convection, the heated air may move from the edges of the fins towards the central axis of the heat sink and directly through a lower surface of the fins through the vents. Accordingly, by positioning the vents across the width of the heat sink, a portion of the heated air is only required to move vertically through the fins. 
     At operation  740 , the fins may more uniformly distributed the generated heat over the heat sink due to simultaneous cross flow over the unvented portion of the heat sink and direct air flow through the vented portion of the heat sink. 
     At operation  750 , the heated air may move away from the light fixture and dissipate into the environment above the heat sink. 
     Reference throughout this specification to “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, “one example” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it is appreciated that the figures provided herewith are for explanation purposes to persons ordinarily skilled in the art and that the drawings are not necessarily drawn to scale. 
     The flowcharts and block diagrams in the flow diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, may be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.