Abstract:
Disclosed is a thin film heat pipe suitable for removal of hot spots in displays such as an LCD, an LED, and a PDP. An exemplary embodiment of the present disclosure provides a thin plate heat pipe including: a body part having a flat plate shape; a through-hole formed in the body part in a longitudinal direction; a plurality of grooves formed on the inner wall of the through-hole and in which a working fluid flows; and a wick formed in at least a part of the through-hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority from Korean Patent Application No. 10-2010-0126771, filed on Dec. 13, 2010, with the Korean Intellectual Property Office, the present disclosure of which is incorporated herein in its entirety by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a thin plate heat pipe usable in cooling electronic components and equipment. 
         [0003]    More particularly, the present disclosure relates to a thin plate heat pipe suitable for removing a hot spot in a flat panel display vertically installed, such as an LCD TV, an LED TV, and a PDP TV. 
       BACKGROUND 
       [0004]    Semiconductor components and systems packaged in electronic equipment have gradually been high-integrated and miniaturized with the development of a semiconductor manufacturing technology. Following this trend, since heat emission density of components included in the electronic equipment is significantly increased, a cooling mechanism for effectively cooling and dissipating the emitted heat is required. In particular, since the electronic equipment is thinned together with miniaturization, an adopted cooling device also needs to be small-sized. 
         [0005]    As an example of the cooling device in the related art which can be adopted in the small-sized electronic equipment, a heat sink, a fan, and a heat pipe having a circular cross section having a diameter of 3 mm or more may be used. 
         [0006]    Since the heat sink can be fabricated with various sizes and thicknesses and is low-priced, the heat sink has been widely used as a basic type of cooling means in the meantime. However, when a significant micro size is required, a heat dissipation rate is relatively low with a decrease in a heat-transfer area. 
         [0007]    The fan is limited in fabricating the fan with the micro size and durability and reliability are relatively low. 
         [0008]    The heat pipe in the related art may be crimped and used to be suitable for a thin-film structure. However, since the small-sized heat pipe having the circular structure cross section has a cross section which is initially designed in a circular shape, when the small-sized heat pipe is crimped to be suitable for electronic equipment having the small-sized and thin-film structure, the heat-transfer performance is significantly reduced due to a structural change of a wick. 
         [0009]    Accordingly, a thin-film type minute heat pipe with a thickness of approximately 2 mm or less suitable for the electronic equipment having the small-sized and thin-film structure needs to be developed. 
         [0010]    In recent years, particularly, the needs for emitted heat cooling and temperature uniformity have been acute depending on performance improvement as well as diversification of products with the rapid growth of a display industry of a liquid crystal display (LCD) TV, a plasma display panel (PDP) TV, and a light emitting diode (LED) TV. In particular, the display is significantly thinner and wider in response to increased consumer&#39;s demands, such that emitted heat cooling and temperature nonuniformity has become problematic. 
         [0011]    Since a display device is vertically installed according to a characteristic, the highest-temperature hot spot is generated at an upper part of the display by an effect of natural convection. A solution for uniformizing a temperature distribution vertically while removing the hot spot is presently required. 
       SUMMARY 
       [0012]    The present disclosure has been made in an effort to achieve high heat-transfer performance in an inclination mode in which a heat pipe is installed to form a predetermined angle with horizontality or in a vertical mode in which the heat pipe is installed in a vertical direction. 
         [0013]    Further, the present disclosure relates to a heat pipe having a very simple mechanical shape and the present disclosure has been made in an effort to provide a thin plate heat pipe having an advantageous inclination angle to further improve productivity by fabricating the heat pipe through simple extrusion and insertion processes and variously apply to small-sized and thin-film structure electronic equipment including a display. 
         [0014]    An exemplary embodiment of the present disclosure provides a thin plate heat pipe including: a body part having a flat plate shape; a through-hole formed in the body part in a longitudinal direction; a plurality of grooves formed on the inner wall of the through-hole and in which a working fluid flows; and a wick formed in at least a part of the through-hole. 
         [0015]    The through-hole may be separated by one or more separation membranes. 
         [0016]    The groove may have a shape including one or more edges. 
         [0017]    The wick may be inserted into an evaporator section of the thin plate heat pipe. 
         [0018]    The wick may be one of a sintered wick or a fabric wick. 
         [0019]    The sintered wick may be inserted into the through-hole separated by one or more separation membranes formed in the through-hole. 
         [0020]    The sintered wick may be made of metal or ceramic. 
         [0021]    The fabric wick may be integrally inserted into the through-hole. 
         [0022]    The inside of the through-hole may be maintained in a vacuum state. 
         [0023]    The thin plate heat pipe may be installed at an incline or vertically. 
         [0024]    The heat pipe may be made of copper or aluminum. 
         [0025]    The thickness of the heat pipe may be 2 mm or less. 
         [0026]    According to the exemplary embodiments of the present disclosure, a thin plate heat pipe for a display that has a thin flat plate shape in which a predetermined through-hole is formed therein and includes polygonally cross-sectional grooves having one or more edges formed on the inner surface of the through-hole to allow a liquid working fluid to flow by capillary force generated from the edge, such that the excellent capillary force can be acquired through structural transformation of the heat pipe itself and heat-transfer performance can be further improved. And the thinned flat plate heat pipe is fabricated in a simple process to further improve productivity and be variously applied to small-sized and thin-film structure electronic equipment. 
         [0027]    According to the exemplary embodiments of the present disclosure, a plurality of separation membranes are formed in one thin plate heat pipe, such that a plurality of passages can be formed using one thin plate heat pipe. 
         [0028]    According to the exemplary embodiments of the present disclosure, not throughout an overall length of the thin plate heat pipe, an additional sintered wick is inserted into the center of the through-hole in a partial range of an evaporator section to generate large capillary force required for the flowing of the working fluid. As such, the large capillary force acquired by inserting the additional sintered wick into the through-hole can show a large merit in heat-transfer performance when a display operates in an inclination mode. 
         [0029]    According to the exemplary embodiments of the present disclosure, by inserting an additional fabric wick into the center of the through-hole in the partial range of the evaporator section of the thin plate heat pipe, the large capillary force required for the flowing of the working fluid can be acquired and weak solidity of the sintered wick can be overcome, thereby achieving a very wide industrial application range. 
         [0030]    The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is a perspective view for describing a thin plate heat pipe according to a first exemplary embodiment of the present disclosure. 
           [0032]      FIG. 2  is a cross-sectional view for describing a thin plate heat pipe according to the first exemplary embodiment of the present disclosure. 
           [0033]      FIG. 3  is a perspective view for describing a thin plate heat pipe according to a second exemplary embodiment of the present disclosure. 
           [0034]      FIG. 4  is a cross-sectional view for describing a thin plate heat pipe according to the second exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    In the following detailed description, reference is made to the accompanying drawing, which form a part hereof. The illustrative embodiments described in the detailed description, drawing, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. 
         [0036]      FIG. 1  is a perspective view for describing a thin plate heat pipe for a display according to a first exemplary embodiment of the present disclosure. 
         [0037]    Referring to  FIG. 1 , the thin plate heat pipe for a display according to the first exemplary embodiment of the present disclosure is constituted by a relatively thin flat plate-shaped body part  100 . The flat plate-shaped body part  100  may be configured as a pipe-type or polyhedron-type metallic plate fabricated using the extrusion process. Body part  100  may be made of copper or aluminum and may be made of other materials except copper and aluminum depending on processability, corrosion resistance, durability, and the shape of a body part. 
         [0038]    A predetermined through-hole  110  is formed in body part  110  to transport a working fluid injected from the outside. Through-hole  110  has an empty space with a predetermined shape. 
         [0039]    A plurality of polygonal cross-section-shaped grooves  120  extended in the same longitudinal direction as through-hole  110  are formed on the inner surface of through-hole  110 . Capillary force is generated by edges of the polygonal cross-section-shaped groove  120  to allow the liquid working fluid to flow. For example, groove  120  may have a polygonal structure having edges with various shapes such as a triangular shape, a rectangular shape, a trapezoidal shape, a hemispherical shape, or a parabolic shape. For a design to generate optimal capillary force, the cross section may be optimally designed in terms of performance and cost by adjusting the shape of groove  120  and the number and angles of the edges, and concave-convex portions of grooves  120 . 
         [0040]    A plurality of separation membranes  140  may be formed in through-hole  110  in order to form a plurality of flow paths. When the width of the heat pipe is small, even one separation membrane may be enough, but when the width is large, the plurality of separation membranes may be formed. 
         [0041]    As described above, in the thin plate heat pipe for a display according to the first exemplary embodiment of the present disclosure, the liquid working fluid flows by the capillary force generated from the edges of polygonal and complicatedly-curved or concave-convex-shaped grooves  120 , instead of a wick in the related art serving as a passage for allowing the liquid working fluid to flow (return) from a condenser section to an evaporator section. 
         [0042]    The liquid working fluid injected while the inside of the thin plate heat pipe for a display according to the first exemplary embodiment of the present disclosure configured as above is maintained in a vacuum state serves to emit heat of the display to the outside and reduce the hot spot while the liquid working fluid performs the phase changes between liquid and gas. Therefore, the type of the liquid requires a characteristic in which the liquid performs the phase changes between liquid and gas within an operational temperature range of the heat pipe. 
         [0043]    The thin plate heat pipe for a display according to the first exemplary embodiment of the present disclosure has a structure in which several grooves  120  extended in the longitudinal direction are formed on the inner surface of through-hole  110  and an additional sintered wick  130  is inserted into the middle of the inner surface of through-hole  110 . 
         [0044]    Since sintered wick  130  may generate relatively large capillary force, the working fluid may flow in a gravity direction (for example, a vertical direction from the bottom to the top) when the display is installed in an inclination mode. In this case, a flowing direction of the working fluid in the inclination mode or a vertical mode may vary depending on detailed situations such as the position of the hot spot and the gravity direction. 
         [0045]    As described above, the capillary force required for the flowing of the working fluid is acquired by even an additionally inserted sintered wick  130  as well as grooves  120  installed on the inner surface of through-hole  110 , such that the heat-transfer performance of the thin plate heat pipe can be significantly improved. 
         [0046]    Meanwhile, sintered wick  130  is not installed throughout an overall length of the heat pipe but at only at least one portion of the evaporator section unlike the sintered wick heat pipes in the related art. Further, as described above, a difference from the related art is even in that sintered wick  130  is positioned at the center of the through-hole on the cross section of the heat pipe. 
         [0047]    Sintered wick  130  may be fabricated using a metallic material and a ceramic based material. Sintered wick  130  is separately inserted into through-hole  110  separated by separation membranes  140 . 
         [0048]      FIG. 2  is a cross-sectional view for describing a thin plate heat pipe according to the first exemplary embodiment of the present disclosure. 
         [0049]    Referring to  FIG. 2 , the cross-sectional structure of through-hole  110 , the shape of groove  120 , and the structure of separation membrane  140  in the thin plate heat pipe according to the first exemplary embodiment of the present disclosure can be verified in detail. 
         [0050]    In particular, additionally inserted sintered wick  130  is positioned in a middle space between grooves  120  installed on the wall of through-hole  110  and is separated into pieces and inserted into each through-hole  110  separated by separation membranes  140 . 
         [0051]      FIG. 3  is a perspective view for describing a thin plate heat pipe for a display according to a second exemplary embodiment of the present disclosure. 
         [0052]    Referring to  FIG. 3 , the thin plate heat pipe for a display according to the second exemplary embodiment of the present disclosure is constituted by a thinned flat plate-shaped body part  300  similarly as in the first exemplary embodiment of the present disclosure. 
         [0053]    As described above, the thin plate heat pipe for a display according to the second exemplary embodiment of the present disclosure has a structure and a function similar to the first exemplary embodiment. That is, the heat pipe has a relatively thin flat plate-shaped outer profile and has a longitudinal through-hole  310  therein. A plurality of longitudinal grooves are formed on the inner surface of through hole  310  to seal the working fluid which performs the phase change within the operational temperature range of the heat pipe, such that the working fluid flows in a liquid phase through the groove and the wick is included in the through-hole. However, the wick additionally inserted into the center of through-hole  310  is constituted by a wick  330  made of a fiber material. 
         [0054]    In the thin plate heat pipe for a display according to the first exemplary embodiment, the wick inserted to generate large capillary force is sintered wick  103 , but in the thin plate heat pipe for a display according to the second exemplary embodiment, a fabric wick  303  is inserted, such that large capillary force can be generated and a structural demerit in which sintered wick  130  tends to be easily broken can be overcome. 
         [0055]    As shown in  FIG. 3 , when fabric wick  330  is inserted into the center of through-hole  310 , the wick is not separated by separation membranes  340  but integrally inserted into through-hole  310  while being not separated with being hung on separation membranes  340 . As shown in  FIG. 3 , separation membranes  340  are not extended throughout the longitudinal direction of body part  300  but may be formed at only the center other than the end. Further, fabric wick  330  may have a structure in which one wick is inserted into one separated through-hole similarly as in sintered wick  103 . 
         [0056]    Meanwhile, since the thin plate heat pipe for a display according to the second exemplary embodiment of the present disclosure has the same operations and effects as the first exemplary embodiment of the present disclosure, a detailed description thereof may refer to the first exemplary embodiment of the present disclosure. 
         [0057]      FIG. 4  is a cross-sectional view for describing a thin plate heat pipe for a display according to the second exemplary embodiment of the present disclosure. 
         [0058]    Referring to  FIG. 4 , the cross-sectional structure of through-hole  310 , the shape of a groove  320 , and the structure of separation membrane  340  in the thin plate heat pipe according to the second exemplary embodiment of the present disclosure can be verified in detail. 
         [0059]    In particular, additionally inserted fabric wick  330  is positioned in the middle space between grooves  320  installed on the wall of through-hole  310  and separation membranes  340  do not separate the entirety of body part  300 , such that fabric wick  330  may be connected throughout through-hole  310 . 
         [0060]    As described above, the thin plate heat pipe for a display according to the first and second exemplary embodiments of the present disclosure has a minute thickness of approximately  2  mm or less and excellent heat dissipation and heat-transfer performance and in particular, shows a very effective operational characteristic in the inclination mode, and as a result, the thin plate heat pipe can be effectively used as means to achieve removal of the hot spot and temperature uniformity of the display. 
         [0061]    Although the thin plate heat pipe for a display according to the exemplary embodiments of the present disclosure has been described, various modifications can be made within the scopes of the appended claims, the detailed description of the present disclosure, and the accompanying drawings are also included in the present disclosure. 
         [0062]    From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.