BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a plasma lighting system, and more particularly, to an eco-friendly cooling apparatus of a plasma lighting system which can prevent components therein from being damaged by shielding foreign substances at the time of installing the plasma lighting system outdoors, and prevent noise at the time of installing it indoors.  
           [0003]    2. Description of the Related Art  
           [0004]    Generally, a plasma lighting system provides high economical efficiency and an idealistic natural light than any other conventional lamps.  
           [0005]    A light emitting principle of the plasma lighting system will be explained. First, microwave (high frequency) generated from a magnetron of a high frequency oscillator makes inert gas in a bulb into plasma, which is ionized status.  
           [0006]    The above plasma status is maintained to make metal compound in the bulb emit light continuously, thereby proving high quantity of light without an electrode.  
           [0007]    The plasma lighting system has following advantages.  
           [0008]    Luminous flux corresponding to that of four metal halide lighting system of 400 W can be generated by one plasma lighting system, energy consumption can be reduced by 20% or more, and an additional stabilizer is not needed since a built-in stabilizer is used.  
           [0009]    Also, since light is emitted by the light emitting principle of the plasma without a filament, the apparatus can be used for a long time without lowering the flux.  
           [0010]    Also, since continuous optical spectrum same as the natural white-light is realized, the plasma lighting system functions similarly to the sun light. The plasma lighting system is useful where the sun light is not streamed into or where color discrimination is made.  
           [0011]    The apparatus does not use fluorescent material to protect visual acuity, and is able to minimize radiation of ultraviolet ray and infrared ray to provide comfortable and eco-friendly lighting environment.  
           [0012]    Hereinafter, constructions of the conventional plasma lighting system will be explained.  
           [0013]    [0013]FIG. 1 is a longitudinal cross-sectional view showing an entire construction of a plasma lighting system in accordance with the conventional art.  
           [0014]    As shown in FIG. 1, the conventional plasma lighting system comprises: a magnetron  20  installed at and upper end of one side of a casing  10  for generating electromagnetic wave; a power supply  30  installed at an upper end of another side of the casing  10  with an opposite state to the magnetron  20  for supplying AC power to the magnetron  20  by boosting into a high voltage; a wave guide  40  connected to an outlet of the magnetron  20  and installed between the magnetron  20  and the power supply  30  for transmitting the electromagnetic wave generated from the magnetron  20  to a bulb; a bulb  50  connected to a middle upper portion of the wave guide  40  and provided with light emitting material, buffer gas, and discharge catalyst material therein for generating light by making the filled fluorescent material into plasma by the electromagnetic wave energy; a resonator  60  including the bulb  50  and passing light generated from the bulb  50  while blocking the electromagnetic wave transmitted from the wave guide  40 ; reflectors  70  attached to a middle upper portion of the casing  10  for containing the resonator and thus intensively reflecting the light generated from the bulb  50 ; a dielectric mirror  80  attached to rear both sides of the bulb  50  and to an inner side of the resonator  60  for passing electromagnetic wave and reflecting light; and a cooling fan assembly  90  installed at a lower side of the casing  10  for cooling the magnetron  20  and the power supply  30 .  
           [0015]    The casing  10  is divided into an upper case  11  and a lower case  12 . An electromagnetic wave passing hole  11   a  for inducing electromagnetic wave by connecting the wave guide  40  and the resonator  60  is formed at a center of the upper case  11 , and air exhaustion holes  11   b  for exhausting air sucked into the casing  10  from outside to the outside by the cooling fan assembly  90  which will be later explained are formed at right and left sides of the electromagnetic wave passing hole  11   a.    
           [0016]    Also, an air suction hole  12   a  is formed at a middle lower portion of the lower case  12 , and air suction passages  12   b  separated right and left by being connected to the air suction hole  12   a  are formed. A fan  92  which will be later explained is installed at a center of the air suction passages  12   b.    
           [0017]    In the meantime, the magnetron  20  and the power supply  30  are located between the air suction passages  12   b  and the air exhaustion holes  11   b  so as to correspond to both outlets of the air suction passages  12   b , and thus fixed to both sides of the wave guide  40 , respectively.  
           [0018]    The wave guide  40  is formed as a ring type, and a magnetron insertion hole  41  is formed to be connected to the magnetron  20  at a peripheral wall of one side, and an electromagnetic wave guide hole  42  having a closed lower end and an opened upper end is formed to be connected to the electromagnetic wave passing hole  11   a  of the upper case  11 .  
           [0019]    The bulb  50  is composed of a light emitting portion  51  formed as a sphere shape by using quartz, a light transmitting substance, so that buffer gas, light emitting material, and discharge catalyst material can be filled therein; and a shaft portion  52  integrally formed at a center of a lower side of the light emitting portion  51  and engaged to a rotation shaft of a bulb motor M.  
           [0020]    Also, the cooling fan assembly  90  is composed of a fan motor  91  fixed to a center of the casing  10 ; and a blower  92  engaged to a rotation shaft of the fan motor  91  to be rotated together and installed at the air suction passage  12   b  of the lower case  12  for sucking air outside of the casing  10  into the casing.  
           [0021]    Operations of the conventional plasma lighting system are as follows.  
           [0022]    First, if a driving signal is inputted to the power supply  30  by a controlling unit, the power supply  30  boosts AC power and then supplies the boosted high voltage to the magnetron  20 . The magnetron  20  is oscillated by the high voltage and generates electromagnetic wave having high frequency. The generated electromagnetic wave is emitted into the oscillator  60  through the wave guide  40  and discharges the material in the bulb  50 , thereby generating light having a peculiar emitting spectrum. The light is reflected forward by the reflector  70  and the dielectric mirror  80 , thereby lightening a space.  
           [0023]    At this time, heat of high temperature is generated from the magnetron  20  and the power supply  30 . Especially, in the magnetron  20 , some high frequency energy which is not emitted among the high frequency energy generated by heat electron disappears by heat, thereby enhancing inner temperature of the casing  10 . According to this, the fan  92  is operated, and as shown in FIG. 1, cool air of outside is sucked into the casing  10  to cool heat generated from the magnetron  20 .  
           [0024]    However, in the conventional lighting system, an inner part of the casing is formed as a single space, thereby having a difficulty in emitting heat. Also, heat of high temperature generated from the magnetron is transmitted to the power supply to destroy inner components thereof, thereby degrading efficiency and life span of the plasma lighting system.  
           [0025]    Also, in the conventional plasma lighting system, air-cooling using the fan is used in order to cool heat generated from the magnetron. In this case, rain water or foreign substance is introduced into an air inlet and an outlet at the time of installing the plasma lighting system outdoors to damage the inner components, and at the time of installing it at the interior, noise generated from the fan caused inconvenience.  
         SUMMARY OF THE INVENTION  
         [0026]    Therefore, an object of the present invention is to provide a cooling apparatus of a plasma lighting system which can prevent rain water or foreign substance from being introduced at the time of installing the plasma lighting system outdoors, remove noise due to a cooling fan at the time of installing it indoors, and prevent heat generated from the magnetron from being transmitted to the power supply in order to prevent the power supply from being damaged.  
           [0027]    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a cooling apparatus of a plasma lighting system comprising: a power supply for supplying a power source; a magnetron for generating electromagnetic wave by the power source from the power supply; a bulb for generating light in accordance with that inert gas is ionized by the electromagnetic wave; and a case unit of a hermetic shape including the magnetron and the power supply therein for cooling heat generated from the magnetron.  
           [0028]    The case unit is composed of a first case installed at an outer side of the magnetron; and a second case hermetically engaged to the first case at an outer side of the power supply.  
           [0029]    The first and second cases are provided with a plurality of heat discharging fins for cooling heat generated from the magnetron at outer surfaces thereof.  
           [0030]    The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:  
         [0032]    [0032]FIG. 1 is a longitudinal cross-section view showing an entire construction of a plasma lighting system in accordance with the conventional art;  
         [0033]    [0033]FIG. 2 is a disassembled perspective view showing a cooling apparatus of a plasma lighting system according to the present invention;  
         [0034]    [0034]FIG. 3 is a longitudinal cross-section view showing a state that a cooling apparatus of a plasma lighting system according to the present invention is assembled;  
         [0035]    [0035]FIG. 4 is an enlarged view of“A” part of FIG. 3, which shows a first embodiment that a case rib is bent towards an inner side of first and second cases and engaged to an adiabatic member;  
         [0036]    [0036]FIG. 5 is an enlarged view of“A” part of FIG. 3, which shows a second embodiment that the case rib is bent towards an outer side of the first and second cases and engaged to the adiabatic member;  
         [0037]    [0037]FIG. 6 is a perspective view showing the first embodiment in which a sealing material is attached to both front surfaces of the adiabatic member according to the present invention;  
         [0038]    [0038]FIG. 7 is a perspective view showing the second embodiment in which the sealing material is attached to edges of the adiabatic member contacted to the first and second cases;  
         [0039]    [0039]FIG. 8 is a longitudinal cross-section view showing an inner part of a case in the cooling apparatus of the plasma lighting system;  
         [0040]    [0040]FIG. 9 is a backside perspective view showing a cover of the cooling apparatus of the plasma lighting system according to the present invention; and  
         [0041]    [0041]FIG. 10 is a perspective view showing an inner part of a resonator of the cooling apparatus of the plasma lighting system according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0043]    Hereinafter, a cooling apparatus of a plasma lighting system will be explained with reference to attached drawings.  
         [0044]    Even if the cooling apparatus of the plasma lighting system has many preferred embodiments, the most preferred embodiment will be explained.  
         [0045]    [0045]FIG. 2 is a disassembled perspective view showing the cooling apparatus of a plasma lighting system according to the present invention, FIG. 3 is a longitudinal cross-section view showing a state that a cooling apparatus of a plasma lighting system according to the present invention is assembled, FIG. 4 is an enlarged view of“A” part of FIG. 3, which shows a first embodiment that a case rib is bent towards an inner side of first and second cases and engaged to an adiabatic member, FIG. 5 is an enlarged view of“A” part of FIG. 3, which shows a second embodiment that the case rib is bent towards an outer side of the first and second cases and engaged to the adiabatic member, FIG. 6 is a perspective view showing the first embodiment in which a sealing material is attached to both front surfaces of the adiabatic member according to the present invention, FIG. 7 is a perspective view showing the second embodiment in which the sealing material is attached to edges of the adiabatic member contacted to the first and second cases, FIG. 8 is a longitudinal cross-section view showing an inner part of a case in the cooling apparatus of the plasma lighting system, FIG. 9 is a backside perspective view showing a cover of the cooling apparatus of the plasma lighting system according to the present invention, and FIG. 10 is a perspective view showing an inner part of a resonator of the cooling apparatus of the plasma lighting system according to the present invention.  
         [0046]    The cooling apparatus of a plasma lighting system, as shown in FIG. 2, comprises: a case unit  110  having a plurality of receiving spaces; a magnetron  120  installed at an inner part of one side of the casing unit  110  for generating electromagnetic wave; a power supply  130  installed at an inner part of another side of the case unit  110  for supplying AC power to the magnetron  120  by boosting into a high voltage; a wave guide  140  connected to an outlet of the magnetron  120  for transmitting the electromagnetic wave generated from the magnetron  120 ; a bulb  150  installed at an upper portion of one side of the wave guide  140  for generating light by exciting the filled material and making into plasma by the electromagnetic wave energy; a resonator  160  located at a front side of the wave guide  140  by covering the bulb  150  for shielding the electromagnetic wave and passing light; reflectors  170  for containing the resonator  160  and thus intensively reflecting the light generated from the bulb  150 .  
         [0047]    As shown in FIGS. 2 and 3, the case unit  110  includes: a first case  111  having a predetermined inner space so as to receive the magnetron  120  for opening one lateral surface and an upper surface thereof; a second case  112  having a predetermined inner space so as to receive the power supply  130  for opening one lateral surface and an upper surface opposite to the first case  111 ; an adiabatic member  113  located between the first case  111  and the second case  112  for insulating the first and second cases  111  and  112 ; and a cover  114  for covering upper surfaces of the first case  111  and the second case  112 .  
         [0048]    Also, as shown in FIG. 4, the first case  111  is formed of a metal having a high heat conductivity such as aluminum as a square box shape, and a case rib  111   a  bent inwardly is formed at one surface contacted to one surface of the adiabatic member  113 .  
         [0049]    Also, an engaging hole  111   b  for bolt-engaging the case rib  111   a  of the first case  111  to a case rib  112   a  of the second case  112  is formed at a center of the case rib  111   a.    
         [0050]    Also, a plurality of heat discharging fins  111   c  for emitting heat generated from the magnetron is formed at an outer surface of the first case  111  by die casting or extrusion.  
         [0051]    As shown in FIG. 8, a heat transfer preventing plate  111   d  of plastic material is formed at an inner space of the first case  111  so as to mount and then seal the magnetron  120 .  
         [0052]    As shown in FIG. 4, the second case  112  is formed of a metal having a high conductivity such as aluminum by the same method as that of the first case  111 , and a case rib  112   a  having an engaging hole  112   b  is formed to be opposite to the case rib  111   a  of the first case  111  at one surface contacted to another surface of the adiabatic member  113 .  
         [0053]    Also, a plurality of heat discharging fins  112   c  for emitting heat generated from the magnetron is formed at an outer surface of the second case  112  by die casting or extrusion like the first case  111 .  
         [0054]    A heat transfer preventing frame  112   d  of plastic material is formed at an inner space of the second case  112  so as to mount and then seal the power supply  130  like the first case  111 .  
         [0055]    As shown in FIGS. 4 and 5, there are a first embodiment in which the first case  111  and the second case  112  are engaged at the inside as aforementioned, and a second embodiment in which the first case  111  and the second case  112  are engaged at the outside so as to easily engage them.  
         [0056]    To this end, as shown in FIG. 5, the case ribs  111   a  and  112   a  curved and extended respectively outwardly at opposite surfaces of the first case  111  and the second case  112  are formed, and engaging holes  111   b  and  112   b  are respectively formed at centers of the case ribs  111   a  and  112   a.    
         [0057]    The adiabatic member  113  is formed as a plate shape of which an upper portion is constantly dented since the bulb motor M or the wave guide  140  is located at the center thereof.  
         [0058]    Also, the adiabatic member  113  includes an adiabatic plate  113   a  having a low heat conductivity and a constant intensity at the center thereof, and a sealing plate  113   b  of rubber attached to both sides of the adiabatic plate  113   a  for closely being attached to the first case  111  and the second case  112 .  
         [0059]    In the meantime, there is a first embodiment in which the sealing plate  113   b  is formed with the same shape as that of the adiabatic plate  113   a  as shown in FIG. 6, and there is a second embodiment in which the sealing plate  113   b  covers only parts where the adiabatic plate  113   a  is contacted to the first case  111  and the second case  112 .  
         [0060]    Also, a plurality of through holes h are formed on the adiabatic plate  113   a  and the sealing plate  113   b  in order to pass an engaging bolt B by opposing to the engaging holes  111   b  and  112   b  of the case ribs  111   a  and  112   a.    
         [0061]    The cover  114  is formed by forming metal such as aluminum as a square plate shape so as to have at least the same plane area as that of the first case  111  and the second case  112 .  
         [0062]    A plurality of heat discharging fins can be formed at an outer surface of the cover  114 , and an electromagnetic wave inducing hole  114   a  is formed at the center of the cover  114  so as to connect the wave guide  140  and the resonator  160 .  
         [0063]    Also, the cover  114  is last assembled in assembly of the case unit  110 , thereby being engaged at outside the respective cases  111  and  112 .  
         [0064]    To this end, cover ribs  111   e  and  112   e  having engaging holes  111   f  and  112   f  at the center thereof are formed around edges of upper surfaces of the cases  111  and  112  by being bent outwardly, and through holes  114   b  are also formed around edges of the cover  114  to correspond to the engaging holes  111   f  and  112   f  of the cover ribs  111   e  and  112   e  by the engaging bolts.  
         [0065]    Also, as shown in FIG. 9, an adiabatic material  114   c  is attached to the edge of the cover  114  in order to shield heat conductivity between the first case  111  and the second case  112 .  
         [0066]    In the meantime, the first case  111 , the second case  112 , and the cover  114  can be formed by the same material having a high heat conductivity, and can be formed by different material one another.  
         [0067]    As shown in FIG. 8, the magnetron  120  provided with an anode, a cathode, and a magnet generates electromagnetic wave so that fluorescent material of the bulb can emit light when a current is applied to the cathode.  
         [0068]    A heat transferring material  121  having a high heat conductivity such as aluminum or copper is coiled or attached to an outer circumference surface of the cathode, and another end of the heat transferring material  121  is fixed to an inner surface of the first case  111 .  
         [0069]    Also, soldering or thermal bond is used at a contact portion between the heat transferring material  121  and the magnetron  120  in order to enhance heat conductivity.  
         [0070]    An outer circumference surface of the power supply  130  can be fixed to an inner surface of the second case  112  by the heat transferring material.  
         [0071]    The wave guide  140  is formed as a rectangular shape of which right and left edges are shorter than upper and lower edges, and installed at a side of the first case  111 . One side of the wave guide  140  is inserted and connected to an outlet of the magnetron  120 , and the other side thereof is connected to an opening of the resonator  160 .  
         [0072]    Also, the bulb  150  includes: a light emitting portion  151  formed as a sphere using quartz, that is, light-transmitting material, and located in the resonator  160  by being filled with buffer gas, luminescent material and discharging catalyst material therein; and a shaft portion  152  formed integrally on lower center portion of the light emitting portion  151  and engaged to a rotary shaft of the bulb motor M installed in the case  110 .  
         [0073]    Also, the bulb motor M is located between the magnetron  120  and the power supply  130  and installed at a groove of the adiabatic member  113 . The bulb motor M is formed as a ball bearing type having a heat resistance, and formed as an enamel coil type which can endure at temperature more than 150°.  
         [0074]    The resonator  160  of a cylindrical shape has an upper surface closed by net and an opened lower surface connected to the outlet of the wave guide  140 .  
         [0075]    Also, as shown in FIG. 10, a dielectric mirror  180  is installed between the wave guide  140  and the light emitting portion  151  of the bulb  150  for transmitting electromagnetic wave and reflecting light forward, and a bulb heat shielding plate  190  of dielectric is installed between the dielectric mirror  180  and the wave guide  140  so as to prevent heat generated from the light emitting portion  151  from penetrating into the case unit  110 .  
         [0076]    The bulb heat shielding plate  190  is formed of quarts or alumina.  
         [0077]    The cooling apparatus of plasma lighting system according to the present invention is assembled as follows and the following effects.  
         [0078]    First, as shown in FIGS.  2  to  8 , the magnetron  120  is mounted at the first case  111  and the wave guide  140  is connected to the outlet of the magnetron  120 . In this state, the outlet of the wave guide  140  is connected to a lower end of the resonator  160  and the magnetron  120  is hermetically engaged by the heat transfer preventing plate  111   d  formed of plastic and etc.  
         [0079]    Then, in a state that the power supply  130  is mounted at the second case  112 , the power supply  130  is sealed by the heat transfer preventing frame  112   d . Next, by locating the adiabatic member  113  between the first case  111  and the second case  112 , the case ribs  111   a  and  112   a  of the first and second cases  111  and  112  are coupled to each other by using an engaging bolt B and an engaging nut (not shown).  
         [0080]    Subsequently, the wave guide  140  is engaged to the magnetron  120 , and the bulb  150  to which the bulb motor M is engaged is located at the center portion of the adiabatic member  113 . Next, opened upper portions of the first and second cases  111  and  112  are covered by the cover  114  and are coupled to the cover ribs  111   e  and  112   e  by the engaging bolt and the engaging nut, thereby completing an assembly of the case unit  110 .  
         [0081]    In the assembled cooling apparatus of plasma lighting system, electromagnetic wave generated from the magnetron  120  is emitted to inside of the resonator  160  through the wave guide  140 , and the material filled in the bulb  150  is discharged by the electromagnetic wave, thereby generating light having its own emitting spectrum. The light is reflected forward by the reflectors  170  and the dielectric mirror  180  and illuminates a space.  
         [0082]    At this time, heat is generated between the magnetron  120  and the power supply  130 . However, the heat is divided into a high temperature portion (inside of the first case) and a low temperature portion (inside of the second case) since the first case  111  and the second case  112  is divided by the adiabatic member  113 . The divided heat passes through the heat discharging fins  111   c  and  112   c  and discharged outwardly.  
         [0083]    Especially, in accordance with that heat of high temperature of the magnetron  120  is transmitted towards the power supply  130 , various inner devices of the power supply which have low heat resistance can be damaged by the heat. However, by locating the adiabatic plate  113   a  of stainless having a low heat conductivity and a constant intensity between the first case  111  and the second case  112 , the heat generated from the magnetron  120  is prevented from being transmitted to the power supply  130 . According to this, overheat of the power supply  130  can be prevented.  
         [0084]    Also, by connecting the magnetron  120  to the first case  111  by the heat transfer material  121  such as a heat pipe or an aluminum bar, heat generated from the magnetron  120  can be fast discharged outwardly through the first case  111 .  
         [0085]    Besides, since the bulb heat shielding plate  190  of dielectric is provided between the bulb  150  and the wave guide  140 , heat generated from the light emitting portion of the bulb  150  can be prevented from being transmitted to inside of the case  110 .  
         [0086]    Also, when the first case  111  and the second case  112  are engaged to each other, the cover  114  is formed integrally and thus temperature of the high temperature portion can be transmitted to the low temperature portion through the cover  114 . However, by attaching the adiabatic material  114   c  to the contact surface between the cover  114  and the cases  111 / 112 , heat conductivity from the high temperature portion to the low temperature portion can be prevented.  
         [0087]    The cooling apparatus of plasma lighting system according to the present invention is divided into the first case and the second case, and the adiabatic member is installed therebetween. According to this, heat of high temperature generated from the magnetron mounted in the first case is transmitted to the power supply mounted in the second case with the minimum, and the heat is discharged to the heat discharging fin of the case, thereby preventing overheat of the power supply without a cooling fan. Also, since an inlet and an outlet of air do not exist, inflow of foreign substances is prevented at the time of installing the lighting system outdoors and noise of the cooling fan can be removed at the time of installing the lighting system indoors.  
         [0088]    As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.
Disclosed is a cooling apparatus of a plasma lighting system comprising: a power supply for supplying a power source; a magnetron for generating electromagnetic wave by the power source from the power supply; a bulb for generating light in accordance with that inert gas is ionized by the electromagnetic wave; and a case unit of a hermetic shape including the magnetron and the power supply therein for cooling heat generated from the magnetron. The plasma lighting system prevents heat of high temperature generated from the magnetron from being transmitted and foreign substance from being introduced.