Patent Publication Number: US-8109661-B2

Title: Illumination apparatus and heat dissipation structure thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 98115957, filed on May 14, 2009. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to an illumination apparatus, and more particularly, to an illumination apparatus having a heat dissipation structure. 
     2. Description of Related Art 
     Most of the illumination apparatuses using on the street are high voltage sodium lamps and mercury lamps. However, the high voltage sodium lamp and the mercury lamp have disadvantages of high power cost and low endurance. With the development of the technology, the light emitting diode (LED) having advantages of high illumination, high endurance, and low power cost is used as the illumination apparatus of the light source to substitute the high voltage sodium lamp and the mercury lamp having disadvantage of high power cost and low endurance. However, the enduring temperature of the LED is 120□, and once the temperature of the LED is more than 120□, the life of the LED may be reduced quickly and the LED may be damaged. Therefore, solving the heat dissipation problem of the illumination apparatus using the LED is important. 
     In addition, the above-mentioned illumination apparatus is used in outdoor environment, so a dustproof problem is important. Please refer to  FIG. 1 , an illumination apparatus  100  includes a housing  110 , a light source module (not described), and a plurality of heat dissipation fins  130 . 
     The housing  110  has a heat dissipation substrate  115  and a plurality of outlets  116 . The outlets  116  are disposed at one side of the housing  110 . Referring to  FIG. 2  at the same time, the light source module  120  is disposed on the bottom surface of the heat dissipation substrate  115 . A plurality of the heat dissipation fins  130  are disposed in the housing  110  and located on the top surface of the heat dissipation substrate  115 . The heat generated by the light source module  120  on the bottom surface of the heat dissipation substrate  115  is dissipated to the heat dissipation fins  130  on the top surface of the heat dissipation substrate  115  through the heat dissipation substrate  115 , and the heat dissipation fins  130  make the heat be carried from the outlets  116  of the housing  110  to the outside of the hosing  110  of the illumination apparatus  100  through the gas convection. 
     However, if the openings of the outlets  116  provided by the housing  110  of the conventional illumination apparatus  100  are larger, the dustproof effect of the illumination apparatus  100  may be reduced, and the dust and other foreign material may enter the housing  110  through the outlets  116  and block up the gap between the heat dissipation fins  130  and result in bad heat dissipation effect of the illumination apparatus  100  and the damage of the light source module  120 . If the openings of the outlets  116  are smaller, the heat stored in the housing  100  may dissipate ineffectively, and result in bad heat dissipation effect of the illumination apparatus  100  and the damage of the light source module  120 . Therefore, how to make the openings of the outlets  116  of the illumination apparatus  100  big enough to dissipate heat and have dustproof effect are problems of the technological area to solve. 
     SUMMARY OF THE INVENTION 
     The invention provides an illumination apparatus having a heat dissipation structure to achieve heat dissipation and dustproof effect of the illumination apparatus. 
     Other objectives and advantages of the invention may be further understood by the disclosures of the invention. 
     To achieve at least one of the above-mentioned objectives or other objectives, an illumination apparatus of an embodiment of the invention includes a housing, a light source module, a plurality of heat sink fins, a shutter structure, and an variable element. The housing has a bottom and an outlet, and the outlet is disposed at one side of the bottom. The light source module is disposed on the bottom of the housing. A plurality of heat sink fins are disposed in the housing and thermal conductivity connected with the light source module. The shutter structure is disposed on the outlet and includes a plurality of guiding plates, a connecting rod, and an operating element, and each of the guiding plates is connected to the connecting rod. The operating element is disposed at one end of the connecting rod and provides an operating force for the connecting rod. The variable element is near the heat sink fins and connected to the connecting rod. The variable element is deformed to exert a force on the connecting rod when the variable element is heated. 
     A heat dissipation structure used in the above-mentioned illumination apparatus according to an embodiment of the invention includes the above-mentioned heat sink fins, the shutter structure, and the variable element. 
     In one embodiment, the illumination apparatus and the heat dissipation structure of the illumination apparatus further include a support. The support surrounds the variable element and is in the shape of a pipe or one end of the support is disposed on the bottom and another end of the support has a hook. The hook surrounds the variable element. The material of the support includes thermal conductivity. 
     In one embodiment, the illumination apparatus and the heat dissipation structure of the illumination apparatus further include a heat dissipation plate, and the heat dissipation plate is thermal conductivity connected between the heat sink fins and the light source module. 
     In one embodiment, the bottom is a heat dissipation surface of the housing. 
     In one embodiment, the shape of the variable element is a circular cylinder, a rectangular cylinder, a triangular cylinder or a spiral, and the material of the variable element is a shape memory alloy module. 
     In one embodiment, the operating element is an elastic spring, a resilient sheet or a counterweight block. 
     In one embodiment, the housing further includes a plurality of inlets, and the inlets are disposed at one side of the bottom of the housing and opposite to the outlet. 
     Comparing with the conventional technology, the embodiment of the invention provides a heat dissipation structure to control the open and close of the outlets of the illumination apparatus, to solve the problem that the outlets of the conventional illumination apparatus may hard to achieve the heat dissipation effect and dustproof effect. 
     Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a three dimensional view of a conventional illumination apparatus. 
         FIG. 2  is a bottom view of a conventional light source module. 
         FIG. 3  is a three dimensional view of an illumination apparatus according to an embodiment of the invention. 
         FIG. 4  is a side view of an illumination apparatus used in outdoors according to an embodiment of the invention. 
         FIGS. 5 and 6  are an enlarged side view of a shutter structure and the operation of a variable element according to an embodiment of the invention. 
         FIGS. 7 and 8  are an enlarged side view of a shutter structure and the operation of a variable element according to an embodiment of the invention. 
         FIGS. 9 and 10  are an enlarged side view of a shutter structure and the operation of a variable element according to an embodiment of the invention. 
         FIG. 11  is a cross-sectional view of the illumination apparatus in  FIG. 3  along line A-A. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
     Please refer to  FIG. 3 , an illumination apparatus  200  includes a heat dissipation apparatus having a housing  210 , a light source module (not shown), a plurality of heat sink fins  230 , a shutter structure  240 , and a variable element  250 . 
     The housing has a bottom  211 , an outlet  216 , and a plurality of inlets  217 . The outlet  216  is disposed at one side  213  of the bottom  211  of the housing  210 , and the inlets  217  is disposed at another side  212  of the bottom  211  of the housing  210  opposite to the outlet  216 . In one embodiment, the bottom  211  is a heat dissipation surface of the housing  210 . The illumination apparatus  200  further includes a lamp rod fixing base  280 , and the lamp rod fixing base  280  is used to fix the illumination apparatus  200  on a lamp rod. 
     Please refer to  FIG. 4 , the light source module  220  is a light emitting diode (LED) apparatus for example. The light source module  220  is disposed on the bottom  211  and provides a light beam and heat. The illumination apparatus  200  is disposed beside the street and has an elevation angle θ. As the illumination apparatus  200  is used to emit the light beam from both sides of the street to the center, as shown by the dotted lines in  FIG. 4 , the elevation angle θ makes the light beam provided by the light source  220  emit to the center of the street. 
     In the embodiment, the illumination apparatus  200  is capable of dissipating heat by adopting natural convection method. The principle of the natural convection is that the air is heated, the density of the air is reduced, and the air generates buoyancy effect, the air flowing direction is shown as the arrow in drawing, so the position of the outlet  216  is higher than the position of the inlet  217 . Through the illumination apparatus  200  disposed in the elevation angle θ, the outlet  216  is disposed at high place, and the inlet  217  is disposed at low place to facilitate the operation of the natural convection air and to dissipate the heat from the light source module  220  stored in the housing  210 . The range of the elevation angle θ of the illumination apparatus  200  is between 10 degrees and 20 degrees. 
     Please refer to  FIG. 3  again, a plurality of heat sink fins  230  are disposed on another surface of the bottom  211  opposite to the light source module  220  and in the housing  210 . The heat sink fins  230  are thermal conductivity connected to the light source module  220  to dissipate the heat of the light source module  220  and to avoid the heat stored in the housing  210  and result in too high temperature to damage the light source module  200 . The heat generated by the light source module  220  located on the bottom surface of the bottom  211  conducts to the heat sink fins  230  located on the top surface of the bottom  211 . The heat is carried from the inner of the housing  210  of the illumination apparatus  200 , through the outlet  216 , to the outside of the housing  210  of the illumination apparatus  200  by the air circulation of the natural convection, so as to speed up the discharge of the heat stored in the housing  210  and make the place between the heat sink fins  230  have an environment temperature. 
     Please refer to  FIGS. 3 ,  5  and  6 , the shutter structure  240  is disposed on the outlet  216  of one side  213  of the housing  210  and includes a plurality of guiding plates  241 , a connecting rod  242 , and an operating element  245 . 
     Each of the guiding plates  241  has a rotating shaft  243  and a connecting point  244 . The connecting points  244  are respectively connected to connecting rod  242 . The operating element  245  is disposed at one end of the connecting rod  242  and provides an operating force for the connecting rod  242 , wherein the operating element  245  is an elastic spring, and the operating force is spring force T. 
     The variable element  250  is near the heat sink fins  230  and disposed between the heat dissipation fins  230 . One end of the variable element  250  is connected to the connecting rod  242 , and the other end is fixed on the lamp rod fixing base  280 . However, in other embodiments, the other end of the variable element  250  may be connected to another substrate of the housing  210  or is fixed on the support element  260 . The material of the variable element  250  is a shape memory alloy module, for example the alloy mixed with nickel and titanium, also called Nitinol. The shape memory alloy module has memory effect, mechanical properties, antifatigue, and corrosion resistance, and may endure great tension and press. The shape of the variable element  250  includes a circular cylinder, a rectangular cylinder, a triangular cylinder or a spiral. 
     In one embodiment, the illumination apparatus  250  further includes a support  260 . The shape the support  260  is a pipe. The support  260  surrounds the variable element  250  to limit the shape variation of the variable element  250 , wherein the material of the support  260  includes high thermal conductivity to conduct the heat generated by the light source module  220  to the variable element  250 . 
     As shown in  FIG. 5 , when the variable element  250  is at normal temperature, the variable element  250  may have deformation and have a free shape. When the temperature rises to a certain temperature from the normal temperature, the variable element  250  is affected by the certain temperature and produces a deformation force F to make the variable element  250  return to the original shape. As shown in  FIG. 6 , the free form variable element  250   a  described by dotted line changes to an original form variable element  250   b  described by full line. The deformation principle of the variable element  250  belongs to a phase transformation of the metal solid state. 
     When the light source module  220  turns off, the environmental temperature between the heat dissipation fins  230  in the housing  210  is at a normal temperature and the environmental temperature is lower than the certain temperature. As shown in  FIG. 5 , the direction of the elastic force T of the elastic spring  245  is shown as the arrow. The elastic force T drives the connecting rod  242  and exerts a tensile force T′ on the free form variable element  250   a  to make the shape of the free form variable element  250  deform as a result of the tensile force T′, and the guiding plates  241  of the shutter structure  240  are driven by the elastic force T and make each of the guiding plates  241  rotate around the spindle  243  and shield the outlet  216 , to prevent the dust or other foreign material entering the inner of the housing  210  from the outlet  216  and block up the gap between the heat dissipation fins  230 , to avoid bad heat dissipation effect of the illumination apparatus  200  and damage the light source module  220 . 
     When the light source module  220  turns on or the illumination apparatus  200  is illuminated intensively by the sun and at high temperature, the environmental temperature between the heat sink fins  230  in the housing  210  is higher than the normal temperature, and the environmental temperature is higher than the certain temperature. As shown in  FIG. 6 , the free form variable element  250   a  generates a deformation force F as a result of the affection of the certain temperature (that is being heated), and returns to the original form variable element  250   b  by the deformation force F. The operating direction of the elastic spring  245  is shown as the arrow. The elastic spring  245  tries pulling the connecting rod  242  to the original first position P 1 . However, the deformation force F drives the connecting rod  242  from the first position P 1  to the second position P 2  and makes each of the guiding plates  241  rotate around the spindle  243 , as shown by arrow, to make the guiding plates  241  of the shutter structure  240  show the outlet  216  to facilitate the heat stored in the housing  210  to dissipate from the outlet  216  by adopting natural convection method. 
     In one embodiment, the operating element  245  is changed to a resilient sheet  246 , and the operating force is the elastic force T. As shown in  FIGS. 7 and 8 , the operating principle of the shutter structure  240   a  and the variable elements  250   a  and  250   b  are the same as the operating principle of the shutter structure  240  and the variable elements  250   a  and  250   b  in  FIGS. 5 and 6 . 
     In one embodiment, the operating element  245  is changed to a counterweight block  247 , and the operating force is the gravity force W. 
     When the light source module  220  turns off, the environmental temperature between the heat dissipation fins  230  in the housing  210  is at a normal temperature, and the environmental temperature is lower than the certain temperature. As shown in  FIG. 9 , the direction of the gravity force W of the counterweight block  247  is shown as the arrow. The gravity force T drives the connecting rod  242  and exerts a tensile force W′ on the free form variable element  250   a , to make the shape of the free form variable element  250  deform as a result of the tensile force W′, and the guiding plates  241  of the shutter structure  240   b  are driven by the gravity force W and make each of the guiding plates  241  rotate around the spindle  243  and shield the outlet  216 , to prevent the dust or other foreign material entering the inner of the housing  210  from the outlet  216 . 
     When the light source module  220  turns on or the illumination apparatus  200  is illuminated intensively by the sun and at high temperature, the environmental temperature between the heat sink fins  230  in the housing  210  is higher than the normal temperature, and the environmental temperature is higher than the certain temperature. As shown in  FIG. 10 , the free form variable element  250   a  generates a deformation force F as a result of the affection of the certain temperature, and returns to the original form variable element  250   b  by the deformation force F. The direction of the gravity force W is shown as the arrow. The gravity force W tries pulling the connecting rod  242  to the original first position P 1 . However, the deformation force F is greater than the gravity force W, so the deformation force F drives the connecting rod  242  from the first position P 1  to the second position P 2  and makes each of the guiding plates  241  rotate around the spindle  243 , to make the guiding plates  241  of the shutter structure  240  show the outlet  216  to facilitate the heat stored in the housing  210  to dissipate from the outlet  216  by adopting natural convection method. 
     One embodiment of the invention further includes a heat dissipation plate  215  and a support  216 , and the support  216  may substitute the pipe shaped support  260 . As shown in  FIG. 11 , the heat dissipation plate  215  is thermal conductivity connected between the light source module  220  and the heat sink fins  230 . One end of the support  261  is disposed on the bottom  211  and another end of the support  261  has a hook  265 . The hook  265  surrounds the variable element  250  to limit the shape deformation of the variable element  250  and to avoid that the returning direction of the deformation force F may not drive the connecting rod  242 . The material of the support  261  includes high thermal conductivity to conduct the heat dissipated by the light source module  220  to the variable element  250 . 
     In summary, the embodiment or embodiments of the invention may have at least one of the following advantages. 
     a. By the arrangement of the variable element  250 , the temperature in the housing  210  may selectively control the guiding plate  241  to shield the outlet  216 , to make the illumination apparatus  200  have dust proof effect, and to make the opening of the outlet  216  be small or large to achieve heat dissipation effect. 
     b. The arrangement of the supports  260  and  261  is used to limit the shape deformation of the variable element  250  to determine the returning direction of the deformation force F, and to make the deformation force F drive the connecting rod  242  smoothly and rotate the guiding plate  241  to shield the outlet  216 . 
     c. The number of the guiding plates  241  of the above-mentioned embodiments is more than one, the guiding plates  241  of the above-mentioned embodiments are used as an example only, and even only one guiding plate  241  in the shutter modules  240 ,  240   a , and  240   b  may achieve the effect of the invention. 
     The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.