Patent Publication Number: US-9841172-B2

Title: Light irradiating device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of Japanese Patent Application No. 2016-006520 filed in the Japan Intellectual Property Office Jan. 15, 2016, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a light irradiating device which includes a light emitting diode (LED) as a light source and irradiates linear light, and more particularly, to a light irradiating device which includes a heat radiating member which radiates heat generated from the LED. 
     BACKGROUND ART 
     According to the related art, a printing device which performs printing using a UV ink which is cured by irradiating an ultraviolet ray is known. In this printing device, an ink is discharged onto a medium from a nozzle of a head and then the ultraviolet ray is irradiated onto a dot formed on the medium. The dot is cured by irradiating the ultraviolet ray to be fixed onto the medium so that satisfactorily printing may be performed on a medium in which it is hard to absorb liquid. For example, the printing device is disclosed in Patent Document 1. 
     In Patent Document 1, disclosed is a printing device including a conveying unit which conveys a printing medium, six heads which are arranged in a conveying direction and discharge cyan, magenta, yellow, black, orange, and green inks, six temporarily curable irradiating units which are arranged in a downstream of a conveying direction between heads to temporarily cure (pinning) dot ink discharged onto the printing medium from each head, and a mainly curable irradiating unit which mainly cures the dot ink to be fixed onto the printing medium. The printing device disclosed in Patent Document 1 cures the dot ink in two steps, that is, the temporary curing step and the mainly curable step, so that bleeding between color inks or spreading of the dot is suppressed. 
     The temporarily curable irradiating unit disclosed in Patent Document 1 is a so-called ultraviolet irradiating device which is disposed above the printing medium to irradiate an ultraviolet ray on the printing medium and irradiates a linear ultraviolet ray in a width direction of the printing medium. In the temporarily curable irradiating unit, an LED is used as a light source in accordance with a demand for a light-weight and a compact size of the printing device. A plurality of LEDs is disposed to be parallel to each other along the width direction of the printing medium. 
     Related Art Document 
     [Patent Document] 
     Japanese Patent Application Laid-Open No. 2013-252720 
     SUMMARY OF THE INVENTION 
     When the LED is used as a light source like the temporarily curable irradiating unit disclosed in Patent Document 1, most of the supplied power is converted into heat so that luminous efficiency and the life span are lowered due to the heat generated from the LED. Further, in the case of a device in which a plurality of LEDs is mounted like the temporarily curable irradiating unit, since the number of LEDs which serve as a light source is increased, the above-mentioned problem may become more serious. Therefore, a light irradiating device which uses the LED as a light source, generally, is configured to suppress the heat generation of the LED using a heat radiating member such as a heat sink. 
     In order to suppress the heat generation of the LED, a heat radiating member such as a heat sink is effectively used. However, in order to efficiently radiate the heat of the LED, a surface area of the heat radiating member needs to be increased as much as possible. However, when the size of the heat radiating member is increased, a size of the entire apparatus is correspondingly increased. Specifically, when a large size heat radiating member is applied to the light irradiating device which is disposed between heads such as the temporarily curable irradiating unit of Patent Document 1, distances between heads are set to be large. Further, heavy-weight and a large size of the printing device are caused, so that a thin device is required. 
     Further, in order to emit light from the LED, a driver circuit which supplies power to the LED is necessary. However, when a plurality of LEDs emits light, like the temporarily curable irradiating unit disclosed in Patent Document 1, the driver circuit also significantly generates heat, so that not only the LEDs, but also the driver circuit needs to efficiently radiate heat. 
     The present invention has been made in an effort to provide a thin light irradiating device which includes a configuration to efficiently radiate heat of the LED and the driver circuit. 
     According to an aspect of the present invention, an light irradiating device extends on an irradiating surface in a first direction and irradiates line shaped light having a predetermined line width in a second direction intersecting the first direction. The light irradiating device includes: a substrate which is substantially parallel to the first direction and the second direction; a plurality of light emitting diode (LED) light sources which is disposed on a surface of the substrate with predetermined intervals along the first direction and emits light in a third direction intersecting the surface of the substrate; a cooling unit which includes a heat transporting unit which at least partially abuts against a rear surface of the substrate, extends in an opposite direction to the third direction from the substrate, and transports heat generated from the LED light source to the opposite direction to the third direction, and a plurality of heat radiating pins which is mounted on the heat transporting unit to radiate heat of the heat transporting unit into the air; an LED driver circuit which drives the plurality of LED light sources; a housing which has an opening sucking and exhausting an external air on one surface of the second direction, accommodates the cooling unit and the LED driver circuit, and forms a wind tunnel in an area where the cooling unit and the LED driving circuit are disposed; and a pan which is provided at a side opposite to the third direction of the cooling unit to guide the external air to a wind tunnel and generate an air current in the wind tunnel, in which the cooling unit is disposed along the one surface and the LED driver circuit is disposed along the other surface which is opposite to the one surface. 
     With this configuration, the LED and the driver circuit are simultaneously cooled. Further, an opening which sucks and exhausts the air is disposed on one surface in the second direction and the outside air is exhausted or sucked to a direction opposite to the third direction (that is, the air current is folded from the second direction to the third direction or from the third direction to the second direction), so that a thin housing in the second direction may be used. 
     The opening may be formed in an area facing the plurality of heat radiating pins in the one direction of the housing so as to expose the plurality of heat radiating pins from the opening. 
     The opening may be formed in a part of an area facing the plurality of heat radiating pins in the one direction of the housing so as to expose a part of the plurality of heat radiating pins at the substrate side from the opening. 
     The opening may be formed more downstream of the third direction than an area facing the plurality of heat radiating pins in the one direction of the housing so as not to expose the plurality of heat radiating pins from the opening. 
     The plurality of heat radiating pins may be a parallel flat type pin which is disposed to be substantially parallel to the substrate so that the heat transporting unit passes therethrough, a radiation type pin which radially protrudes from an outer periphery of a tubular heat radiating member into which the heat transporting unit is inserted, or a corrugated pin which is provided in the heat transporting unit. When the plurality of heat radiating pins is parallel flat type pins, the parallel flat type pin may have a plurality of through holes through which the air passes. 
     Further, the outside air may flow between the plurality of heat radiating pins from the opening and flow along the LED driver circuit to be exhausted from the fan. 
     Further, the outside air may flow from the fan to flow along the LED driver circuit and pass between the plurality of heat radiating pins to be exhausted from the opening. 
     The heat transporting unit may be at least one heat pipe or at least one coolant flow channel in which coolant is included. When the heat transport unit is the plurality of heat pipes, the heat pipes may be offset in the second direction with respect to a heat pipe adjacent thereto along the first direction. 
     When a length of the cooling unit in the second direction is L 1  and a length of the heat radiating pin in the second direction is L 2 , the following conditional expression 1 may be satisfied.
 
L2&lt;L1  (1)
 
     The light may be light in an ultraviolet wavelength band. 
     According to another aspect of the present invention, a light irradiating device extends on an irradiating surface in a first direction and irradiates line shaped light having a predetermined line width in a second direction intersecting the first direction. The light irradiating device includes: a substrate which is substantially parallel to the first direction and the second direction; a plurality of light emitting diode (LED) light sources which is disposed on a surface of the substrate with predetermined intervals along the first direction and emits light in a third direction intersecting the surface of the substrate; a cooling unit which includes a heat transporting unit which is at least partially in contact with a rear surface of the substrate, extends in an opposite direction to the third direction from the substrate, and transports heat generated from the LED light source to the opposite direction to the third direction, and a plurality of heat radiating pins which is mounted on the heat transporting unit to radiate heat of the heat transporting unit into the air; an LED driver circuit which drives the plurality of LED light sources; a housing which has an opening sucking and exhausting an external air on one surface of the second direction, accommodates the cooling unit and the LED driver circuit, and forms a wind tunnel in an area where the cooling unit and the LED driving circuit are disposed; and a fan which is provided between the opening and the heat radiating pin in the third direction to guide the external air to the wind tunnel and generate an air current in the wind tunnel, in which the housing has an opening which sucks or exhausts the outside air, on one surface in the second direction, the LED driver circuit is disposed along the one direction and the cooling unit is disposed along the other surface which is opposite to the one surface. 
     As described above, according to the present invention, a thin light irradiating device which includes a configuration to efficiently radiate heat of the LED and the driver circuit is implemented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exterior appearance of a light irradiating device according to a first exemplary embodiment of the present invention. 
         FIG. 2  is a front view of a light irradiating device according to a first exemplary embodiment of the present invention. 
         FIG. 3  is a cross-sectional view taken along line A-A of  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along the line B-B of  FIG. 3 . 
         FIG. 5  is a view illustrating a shape in which an upper side panel is removed from a light irradiating device according to a first exemplary embodiment of the present invention. 
         FIG. 6  is a view illustrating a modification embodiment of a light irradiating device according to a first exemplary embodiment of the present invention. 
         FIG. 7  is a cross-sectional view of an inner configuration of a light irradiating device according to a second exemplary embodiment of the present invention. 
         FIG. 8  is a cross-sectional view taken along the line B-B of  FIG. 7 . 
         FIG. 9  is a view illustrating a shape in which an upper side panel is removed from a light irradiating device according to a second exemplary embodiment of the present invention. 
         FIG. 10  is a cross-sectional view of an inner configuration of a light irradiating device according to a third exemplary embodiment of the present invention. 
         FIG. 11  is a cross-sectional view taken along the line B-B of  FIG. 10 . 
         FIG. 12  is a view illustrating a shape in which an upper side panel is removed from a light irradiating device according to a third exemplary embodiment of the present invention. 
         FIG. 13  is a cross-sectional view of an inner configuration of a light irradiating device according to a fourth exemplary embodiment of the present invention. 
         FIG. 14  is a cross-sectional view taken along the line B-B of  FIG. 13 . 
         FIG. 15A  is a cross-sectional view of an inner configuration of a light irradiating device according to a fifth exemplary embodiment of the present invention, and  FIG. 15B  is a view explaining an air flow in a part D of  FIG. 15A . 
         FIG. 16  is a perspective view of an exterior appearance of a light irradiating device according to a fifth exemplary embodiment of the present invention. 
         FIG. 17  is a cross-sectional view illustrating a modification embodiment a light irradiating device according to a fifth exemplary embodiment of the present invention. 
         FIG. 18A  is a cross-sectional view of an inner configuration of a light irradiating device according to a sixth exemplary embodiment of the present invention, and  FIG. 18B  is a view explaining an air flow in a part E of  FIG. 18A . 
         FIG. 19A  is a cross-sectional view of an inner configuration of a light irradiating device according to a seventh exemplary embodiment of the present invention, and  FIG. 19B  is a view explaining an air flow in a part F of  FIG. 19A . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. Further, in the drawings, like elements are denoted by like reference numerals, and description thereof will be omitted. 
     First Exemplary Embodiment 
       FIG. 1  is a perspective view of an exterior appearance of a light irradiating device  1  according to a first exemplary embodiment of the present invention. Further,  FIG. 2  is a front view of the light irradiating device  1 ,  FIG. 3  is a cross-sectional view (a cross-sectional view of a Y-Z plane) taken along line A-A of  FIG. 2 , and  FIG. 4  is a cross-sectional view taken along the line B-B of  FIG. 3 . Further,  FIG. 5  is a view illustrating a shape in which an upper side panel  102  of the light irradiating device  1  is removed, and specifically,  FIG. 5A  is a top view and  FIG. 5B  is an enlarged view of a part C of  FIG. 5A . The light irradiating device  1  according to this exemplary embodiment is a light source device which is mounted in a printing device to cure an ultraviolet curable ink or an ultraviolet curable resin. For example, the light irradiating device  1  is disposed above an object to be irradiated to emit a linear ultraviolet ray to the object to be irradiated. Further, in this specification, as illustrated in a coordinate of  FIG. 1 , a direction in which a light emitting diode (LED) element  206  which will be described below emits an ultraviolet ray is defined as a Z-axis direction, an arrangement direction of the LED elements  206  is defined as an X-axis, and a direction perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction. 
     As illustrated in  FIG. 1 , the light irradiating device  1  according to the exemplary embodiment includes a thin box shaped case (housing)  100  in which light source units  200 A and  200 B are accommodated. The case  100  includes a window  105  formed of glass through which the ultraviolet ray is emitted, in the front side. Further, on an upper side panel  102  (one surface to which a cooling device  210  which will be described below is disposed to be close) of the case  100 , a plurality of suction ports  102   a  (openings) through which air flows into the case  100  from the outside is formed and driver circuits  300 A and  300 B are mounted at an inner side of a lower side panel  103  (see  FIGS. 3 and 4 ). Further, fans  400 A and  400 B which flow air in the case  100  from the outside, generate an air current in the case  100 , and exhaust air in the case  100  are mounted on a rear surface (an end face opposite to the Z-axis direction) of the case  100 . 
     As illustrated in  FIGS. 2, 4, and 5 , the light irradiating device  1  according to the exemplary embodiment includes two light source units  200 A and  200 B, two driver circuits  300 A and  300 B in the case  100 . Two light source units  200 A and  200 B are devices having the same configuration which are arranged in the X-axis direction and the driver circuits  300 A and  300 B are electronic circuits which drive the light source units  200 A and  200 B, respectively. 
     As illustrated in  FIGS. 2 and 3 , each of the light source units  200 A and  200 B includes a rectangular substrate  204  which is parallel to the X-axis direction and the Y-axis direction, twenty LED elements  206  which are disposed by two columns by ten LED elements on the substrate  204 , and a cooling device  210 . As described above, in the exemplary embodiment, the light source unit  200 A and the light source unit  200 B have the same configuration, so that a configuration of the light source unit  200 A will be representatively described in detail. 
     The twenty LED elements  206  of the light source unit  200 A are disposed on a surface of the substrate  204  (see  FIG. 2 ) while aligning an optical axis to the Z-axis direction. An anode pattern (not illustrated) and a cathode pattern (not illustrated) which supply power to each of the LED elements  206  are formed on the substrate  204 . Each LED element  206  is soldered to the anode pattern and the cathode pattern to be electrically connected to each other. Further, the substrate  204  is electrically connected to the driver circuit  300 A by a wiring cable which is not illustrated. Further, a driving current is supplied to each LED element  206  from the driver circuit  300 A, by means of the anode pattern and the cathode pattern. When the driving current is supplied to each LED element  206 , an ultraviolet ray (for example,  365  nm of a wavelength) with a light quantity in accordance with the driving current is emitted from each LED element  206  and a linear ultraviolet ray parallel to the X-axis direction is emitted from the light source unit  200 A. In the exemplary embodiment, the linear ultraviolet ray from the light source unit  200 A and the linear ultraviolet ray from the light source unit  200 B are configured to be continuous in the X-direction. Further, a driving current which is supplied to each LED element  206  is adjusted to allow each LED element  206  of the exemplary embodiment to emit the ultraviolet ray having substantially the same light quantity. Further, the linear ultraviolet ray emitted from the light source units  200 A and  200 B has substantially uniform light quantity distribution in the X-axis direction. 
     The cooling device  210  is a member which radiates heat generated from the light source unit  200 A and cools the LED element  206 . As illustrated in  FIGS. 1, 3 , and  5 , the cooling device  210  according to the exemplary embodiment is configured by a metal (for example, copper or aluminum) support plate  211  which extends in the X-axis direction in the case  100  and has a substrate  204  mounted on one end face (a surface facing a front side of the case  100 ), eight heat pipes  212  (heat transporting units) which have one end closely fixed to the other end (a surface opposite to a surface on which the substrate  204  is disposed) of the support plate  211  and transport heat generated in each LED element  206 , and a plurality of heat radiating pins  214  which is closely fixed to each heat pipe  212 . When a driving current flows in each LED element  206  and the ultraviolet ray is emitted from each LED element  206 , the temperature of the LED element  206  is increased due to self-heating and the luminous efficiency is significantly lowered. Therefore, according to the exemplary embodiment of the present invention, the cooling device  210  is provided to be closely attached onto a rear surface of the substrate  204  to conduct the heat generated in the LED element  206  to the cooling device  210  by means of the substrate  204 , thereby forcibly radiating the heat. Further, in the exemplary embodiment, the heat radiating pin  214  of the cooling device  210  is disposed along the upper side panel  102  of the case  100 . The heat radiating pin  214  and the driver circuit  300 A disposed on the lower side panel  103  are cooled by air which flows into the plurality of suction ports  102   a  from the outside (details will be described below). 
     The heat pipe  212  is a hollow metal sealed pipe (for example, metal such as copper, aluminum, iron, or magnesium or an alloy including the same) having a substantially circular cross-section in which an operating fluid (for example, water, alcohol, or ammonia) is sealed at a reduced pressure. As illustrated in  FIG. 3 , the heat pipe  212  of the exemplary embodiment has substantially an L shape as seen from the X-axis direction. The heat pipe  212  is configured by a curved part  212   a  which is closely attached onto a rear surface of the support plate  211 , and an arm unit  212   b  which protrudes in a negative direction of the Z-axis direction (that is, an opposite direction to an ultraviolet ray emission direction) from the curved part  212   a.  The curved part  212   a  is fixed to the support plate  211  so as to be closely attached to another end face of the support plate  211  through the fixture  220  and is thermally coupled to the substrate  204 . Each of the light source units  200 A and  200 B of the exemplary embodiment includes eight heat pipes  212  (see  FIG. 5 ) which are arranged in the X-axis direction. As seen from the Z-axis direction, the arm units  212   b  of the eight heat pipes  212  are offset to be divided into two upper and lower stages to be alternately disposed (see  FIG. 4 ). The arm units  212   b  are configured to form a gap in the Y-axis direction between the arm units  212   b  of the heat pipe  212  which is adjacent thereto in the X-axis direction (that is, disposed to form a zigzag pattern). As described above, according to the exemplary embodiment, between the arm units  212   b  of the heat pipe  212 , gaps in the X-axis direction and the Y-axis direction are provided so that the air may easily flow between the arm units  212   b  of the heat pipes  212  (details will be described below). 
     The heat radiating pin  214  is a rectangular metal (for example, metal such as copper, aluminum, iron, or magnesium or an alloy including the same) member. As illustrated in  FIGS. 3 to 5 , eight through holes  214   c  through which arm units  212   b  of the heat pipes  212  are inserted are formed in each heat radiating pin  214  of the exemplary embodiment. In the exemplary embodiment, the arm units  212   b  of the heat pipes  212  are sequentially inserted into 70 sheets of heat radiating pins  214  and the heat radiating pins  214  are disposed with a predetermined interval along the Z-axis direction (that is, parallel to the substrate  204 ) (see  FIGS. 3 and 5 ). Further, each heat radiating pin  214  is mechanically and thermally coupled to each arm unit  212   b  by welding, soldering, or pressing, in each through hole  214   c.  Further, as illustrated in  FIG. 5B , the heat radiating pin  214  of the exemplary embodiment is configured by a flat part  214   a  which is parallel to the X-axis direction and the Y-axis direction as seen from the Y-axis direction and a folded part  214   b  which is folded to the negative direction of the Z-axis direction at both ends of the X-axis direction of the flat part  214   a.  The folded part  214   b  is configured to be in contact with the flat part  214   a  of the heat radiating pin  214  which is adjacent thereto. The outside air which flows into the light source unit  200 A and the light source unit  200 B does not interfere in the X-axis direction (that is, is not leaked to the X-axis direction) by providing the folded part  214   b,  so that the light source unit  200 A and the light source unit  200 B may be closely disposed. In other words, even though the light source unit  200 A and the light source unit  200 B are closely disposed, the air which is sucked by the light source unit  200 A and the air which is sucked by the light source unit  200 B do not interfere with each other. 
     Further, as illustrated in  FIG. 3 , a length L 2  of the heat radiating pin  214  of the exemplary embodiment in the Y-axis direction is set to be smaller than a length L 1  of the support plate  211  in the Y-axis direction (that is, a relationship of L 2 &lt;L 1  is satisfied) and the driver circuit  300 A is disposed at a lower side (a side opposite to the Y-axis direction in  FIG. 3 ) than the cooling device  210 . 
     When a driving current flows in each LED element  206  and the ultraviolet ray is emitted from each LED element  206 , the temperature of the LED element  206  is increased due to self-heating. But the heat generated in each LED element  206  is quickly conducted (moves) to the folded part  212   a  of the heat pipe  212  by means of the substrate  204  and the support plate  211 . When the heat moves to the folded part  212   a  of the heat pipe  212 , the operating fluid in the heat pipe  212  absorbs the heat to be evaporated and steam of the operating fluid moves through a hollow part in the arm unit  212   b,  so that the heat of the folded part  212   a  moves to the arm unit  212   b.  Further, the heat which moves to the arm unit  212   b  moves to the plurality of heat radiating pins  214  which is coupled to the arm unit  212   b  to be radiated from the heat radiating pin  214  into the air. When the heat is radiated from the heat radiating pin  214 , the temperature of the arm unit  212   b  is correspondingly lowered. Therefore, the steam of the operating fluid in the arm unit  212   b  is cooled to return to a liquid state and move to the folded part  212   a.  The operating fluid which moves to the folded part  212   a  is used to absorb heat which is newly conducted by means of the substrate  204  and the support plate  211 . 
     As described above, in the exemplary embodiment, the operating fluid in the heat pipe  212  circulates between the folded part  212   a  and the arm unit  212   b  to quickly move the heat generated in each LED element  206  to the heat radiating pin  214  and efficiently radiate the heat from the heat radiating pin  214  into the air. By doing this, the temperature of the LED element  206  is not excessively increased and the luminous efficiency is not significantly lowered. 
     The fans  400 A and  400 B are devices which flow the air into the light source units  200 A and  200 B from the outside and generate air current in the case  100 , and exhaust the air in the case  100  to the outside. As illustrated in  FIGS. 1 and 3 , in the exemplary embodiment, a plurality of suction ports  102   a  is formed in an area facing the heat radiating pin  214  of the upper side panel  102  to expose the heat radiating pin  214  from the suction port  102   a.  Further, as illustrated by an arrow (an air flow) in  FIG. 3 , when the fans  400 A and  400 B rotate, the outside air is flowed through the plurality of suction ports  102   a  and passes between the heat radiating pins  214  of the light source unit  200 A and the light source unit  200 B, so that the heat of the heat radiating pin  214  is efficiently radiated to the air. Further, the air which passes between the heat radiating pins  214  touches the driver circuit  300 A which is disposed at a lower side (a side opposite to the Y-axis direction in  FIG. 3 ) than the cooling device  210 . Therefore, not only the heat radiating pin  214 , but also the driver circuit  300 A is cooled. 
     As described above, in the exemplary embodiment, a sort of wind tunnel is formed in the case  100 , the cooling device  210  of the light source unit  200 A and the light source unit  200 B and the driver circuits  300 A and  300 B are disposed along the Y-axis direction, and the air is flowed in a direction opposite to the Y-axis direction. Therefore, the cooling device  210  of the light source unit  200 A and the light source unit  200 B and the driver circuits  300 A and  300 B are simultaneously and efficiently cooled. Further, in the exemplary embodiment, an opening direction of the plurality of suction ports  102   a  is set to the Y-axis direction and an exhaust direction of the fans  400 A and  400 B is set to a direction opposite to the Z-axis direction, so that a light irradiating device  1  which is thin in the Y-axis direction is obtained. 
     Since a cooling capacity of the cooling device  210  is determined by a heat transporting amount of the heat pipe  212  and a heat radiating amount of the heat radiating pin  214 , it is preferable that the number of heat pipes  212  and heat radiating pins  214  is large, from the point of view of the cooling capacity. However, the cooling capacity of the cooling device  210  is determined in accordance with a consumed cooling performance. However, when the number of heat pipes  212  is increased along the X-axis direction, the gap between adjacent heat pipes  212  is narrowed and the air flow is deteriorated. Therefore, in order to solve the above-mentioned problem, in the exemplary embodiment, as seen from the Z-axis direction, the arm units  212   b  of the eight heat pipes  212  are offset to be divided into two upper and lower stages to be alternately disposed (see  FIG. 4 ). A gap is formed in the Y-axis direction between the arm units  212   b  of the heat pipe  212  which are adjacent to each other in the X-axis direction. 
     Even though the exemplary embodiment has been described above, the present invention is not limited to the above-described configuration and may be modified in various forms within a scope of a technical spirit of the present invention. 
     For example, in the exemplary embodiment, even though it is configured that the heat of the substrate  204  is received by the support plate  211  and the heat of the support plate  211  is radiated by the heat pipe  212  and the heat radiating pin  214 , the support plate  211  is not necessarily required, but the substrate  204  and the heat pipe  212  may be directly bonded to each other. 
     Further, in the exemplary embodiment, it is described that a cross-section of the heat pipe  212  is a substantially circular shape, but the present invention is not limited to this configuration. For example, the cross-section of the heat pipe  212  may be a rectangle or a flat plate shape. Further, in the exemplary embodiment, even though it is described that an end of the heat pipe  212  is closely attached onto the support plate  211 , for example, the end of the heat pipe  212  may be inserted in the support plate  211  to be thermally coupled thereto. 
     Further, even though it is described that the cooling device  210  of the exemplary embodiment has 70 sheets of heat radiating pins  214 , the number of heat radiating pins  214  may be appropriately changed in accordance with a quantity of heat to be radiated. 
     Further, the light irradiating device  1  of the exemplary embodiment is a device which irradiates an ultraviolet ray, but the present invention is not limited to this configuration. Further, the present invention may be applied to a device which irradiates irradiating light (for example, visible light such as white light or infrared ray) of a different wavelength band. 
     Further, in the exemplary embodiment, even though a configuration in which twenty LED elements  206  are arranged on the substrate  204  of the light source unit  200 A and the light source unit  200 B has been suggested, the number of LED elements  206  may be appropriately changed in accordance with a specification. Further, N columns (N is 2 or larger integer) of LED elements  206  may be arranged along the Y-axis direction. 
     Further, in the exemplary embodiment, even though it is described that the fans  400 A and  400 B are exhaust fans which exhaust air in the case  100  to the outside, for example, the fans may be configured by suction fans. In this case, the suction port  102   a  (that is, an opening formed on the upper side panel  102 ) may be the exhaust port. 
     (Modification Embodiment of First Exemplary Embodiment) 
       FIG. 6  is a view illustrating a modification embodiment of a heat radiating pin  214  provided in a light irradiating device  1  according to a first exemplary embodiment of the present invention. A heat radiating pin  214 ′ of the modification embodiment includes a plurality of through holes  214   d,  which is different from the heat radiating pin  214  of the first exemplary embodiment. 
     As described above, when the plurality of through holes  214   d  is formed in the heat radiating pin  214 ′, the air current generated in the case  100  also passes through the through hole  214   d,  so that an air quantity which passes between the heat radiating pins  214 ′ is increased, thereby efficiently cooling the heat radiating pins  214 ′. 
     Second Exemplary Embodiment 
       FIGS. 7 to 9  are views explaining an inner configuration of a light irradiating device  1 A according to a second exemplary embodiment of the present invention,  FIG. 7  is a cross-sectional view of a Y-Z plane,  FIG. 8  is a cross-sectional view taken along the line B-B of  FIG. 7 , and  FIG. 9  is a top view when the upper side panel  102  of the light irradiating device  1 A is removed. 
     As illustrated in  FIGS. 7 to 9 , in the light irradiating device  1 A of the exemplary embodiment, a cooling device  210 A of each of a light source unit  200 AA and a light source unit  200 BA includes three heat pipes  212 A, a corrugated pin  214 A formed between heat pipes  212 A, and a connecting unit  230 A which connects leading edges of the three heat pipes  212 A and a folded part  212 Aa of each heat pipe  212 A is integrally formed in a support plate  211 A, which is different from the light irradiating device  1  of the first exemplary embodiment. 
     Each heat pipe  212 A has the same function as the heat pipe  212  of the first exemplary embodiment. As an operating fluid moves between the folded part  212 Aa and the arm unit  212 Ab of each heat pipe  212 A, the heat of the support plate  211 A moves to the arm unit  212 Ab. Further, the heat moves from the arm unit  212 Ab to the corrugated pin  214 A which is formed in a zigzag shape and is radiated into the air from the corrugated pin  214 A. 
     Further, as illustrated in  FIG. 9 , in the exemplary embodiment, the folded part  212 Aa of each heat pipe  212 A communicates in the support plate  211 A in the X-axis direction and the leading edge of each heat pipe  212 A communicates in the connecting unit  220 A in the X-axis direction. Therefore, the operating fluid of each heat pipe  212 A moves between the heat pipes  212 A by means of the support plate  211 A and the connecting unit  230 A. 
     Similarly to the exemplary embodiment, when the folded part  212 Aa of each heat pipe  212 A and the support plate  211 A are integrally formed, heat resistance between each heat pipe  212 A and the support plate  211 A may be lowered. Further, in the exemplary embodiment, the cooling device  210 A is configured to include three independent heat pipes  212 A and the connecting unit  230 A which connects the leading edges of three heat pipes  212 A. However, a circulating heat pipe in which the heat pipes  212 A and the connecting units  230 A are integrated may be applied. Further, three heat pipes  212 A are not necessarily provided, for example, the cooling device  210 A may bond the corrugated pin  214 A to one heat pipe  212 A by welding or soldering. 
     Third Exemplary Embodiment 
       FIGS. 10 to 12  are views explaining an inner configuration of a light irradiating device  1 B according to a third exemplary embodiment of the present invention,  FIG. 10  is a cross-sectional view of a Y-Z plane,  FIG. 11  is a cross-sectional view taken along the line B-B of  FIG. 10 , and  FIG. 12  is a top view when the upper side panel  102  of the light irradiating device  1 B is removed. 
     As illustrated in  FIGS. 10 to 12 , in the light irradiating device  1 B of the exemplary embodiment, a cooling device  210 B of each of a light source unit  200 AB and a light source unit  200 BB includes a pair of coolant flow channels  212 B, a corrugated pin  214 B formed between the coolant flow channels  212 B, and a pump unit  240 B which is connected to leading edges of the pair of coolant flow channels  212 B and circulates a coolant (for example, water or antifreeze liquid) which is filled in the pair of coolant flow channels  212 B, which is different from the light irradiating device  1 A of the second exemplary embodiment. 
     The coolant flow channels  212 B are formed of metal pipes and the coolant therein moves to move the heat of the coolant to the corrugated pin  214 B. That is, when the coolant in the coolant flow channel  212 B circulates by the pump unit  240 B, the heat of the support plate  211 B moves to the coolant flow channels and also moves from the coolant flow channel  212 B to the corrugated pin  214 B which is formed in a zigzag shape. 
     As described above, the heat pipe  212 A of the second exemplary embodiment is replaced by the coolant flow channel  212 B in which the coolant is filled and the coolant in the coolant flow channel  212 B may be circulated by the pump unit  240 B. Further, in the exemplary embodiment, even though it is configured that the coolant in the coolant flow channel  212 B is circulated by the pump unit  240 B, a known boiling cooling technique may be applied. In this case, the pump unit  240 B is not necessary. 
     Fourth Exemplary Embodiment 
       FIGS. 13 and 14  are views explaining an inner configuration of a light irradiating device  1 C according to a fourth exemplary embodiment of the present invention,  FIG. 13  is a cross-sectional view of a Y-Z plane, and  FIG. 14  is a cross-sectional view taken along the line B-B of  FIG. 13 . 
     As illustrated in  FIGS. 13 and 14 , in the light irradiating device  1 C of the exemplary embodiment, a cooling device  210 C of each of a light source unit  200 AC and a light source unit  200 BC includes a substantially cylindrical heat radiating member  214 C, instead of the rectangular panel shaped heat radiating pin  214 , a suction port  102   a  is formed only on a substrate  204  of the upper side panel  102  of the case  100 , and the heat radiating member  214 C is not exposed from the suction port  102   a,  which is different from the light irradiating device  1  of the first exemplary embodiment. 
     The heat radiating member  214 C is a metal member which is mounted (inserted) on the arm unit  212   b  of the heat pipe  212 . A plurality of pins  214 Ca (a radiation type pins) which radially protrudes as seen from the Z-axis direction is formed on an outer periphery of the heat radiating member  214 C, and the heat of the arm unit  212   b  of each heat pipe  212  is discharged into the air by the plurality of pins  214 Ca. 
     As described above, in the exemplary embodiment, since the heat radiating member  214 C having the plurality of pins  214 Ca is mounted in the arm unit  212   b  of each heat pipe  212 , it is configured that the suction port  102   a  is formed only on the substrate  204  of the upper side panel  102  of the case  100  to efficiently flow the air on the surface of the pin  214 Ca and the heat radiating member  214 C is not exposed from the suction port  102   a.  That is, the suction port  102   a  is formed in the Z-axis direction further than the area facing the pin  214 Ca of the upper side panel  102  so as not to expose the pin  214 Ca from the suction port  102   a.  When the fans  400 A and  400 B rotate, outside air flows from the suction port  102   a  and passes between the pins  214 Ca of the heat radiating members  214 C of the light source unit  200 A and the light source unit  200 B, so that the heat of the pin  214 Ca is efficiently radiated in the air. Further, as illustrated in  FIG. 13 , the air which flows from the suction port  102   a  touches the driver circuit  300 A disposed at a lower side than the cooling device  210 C (a side opposite to the Y-axis direction in  FIG. 13 ). Therefore, similarly to the first exemplary embodiment, according to the configuration of the exemplary embodiment, not only the pin  214 Ca, but also the driver circuit  300 A is cooled. 
     Fifth Exemplary Embodiment 
       FIG. 15  is a view explaining an inner configuration of a light irradiating device  1 D according to a fifth exemplary embodiment of the present invention,  FIG. 15A  is a cross-sectional view of a Y-Z plane, and  FIG. 15B  is a view explaining an air flow in a part D of  FIG. 15A . Further,  FIG. 16  a perspective view of an exterior appearance of a light irradiating device  1 D. 
     As illustrated in  FIGS. 15 and 16 , in the light irradiating device  1 D of the exemplary embodiment, a suction port  102   a  is formed only on the substrate  204  of the upper side panel  102  of the case  100 , which is different from the light irradiating device  1  according to the first exemplary embodiment. That is, the suction port  102   a  of the exemplary embodiment is formed in a part of an area facing the pin  214  of the upper side panel  102  so as to expose a part of the substrate  204  of the pin  214  from the suction port  102   a.    
     When the fans  400 A and  400 B of the exemplary embodiment rotate, the outside air flows from the suction port  102   a  into the case  100 . The air which flows from the suction port  102   a  touches the driver circuit  300 A disposed at a lower side than the cooling device  210  (a side opposite to the Y-axis direction in  FIG. 13 ). Therefore, similarly to the first exemplary embodiment, according to the configuration of the exemplary embodiment, not only the heat radiating pin  214 , but also the driver circuit  300 A is cooled. 
     Further, in the exemplary embodiment, the outside air does not flow from the heat radiating pin  214  which does not face the suction port  102   a.  However, as illustrated in  FIG. 15B , when an air current in an opposing direction to the Z-axis direction is generated at a lower side of the heat radiating pin  214 , an inflow wind is generated between the heat radiating pins  214 , thereby cooling the heat radiating pins  214 . 
     Further, as a modification embodiment of the exemplary embodiment, as illustrated in  FIG. 17 , it may be configured such that the heat radiating pin  214  is not exposed through the suction port  102   a.  That is, similarly to the fourth exemplary embodiment, the suction port  102   a  is formed at the downstream of the Z-axis direction further than the area facing the pin  214  of the upper side panel  102  so as not to expose the pin  214  from the suction port  102   a.  Further, in this case, since the heat radiating pin  214  does not face the suction port  102   a,  the outside air does not flow between the heat radiating pins  214 . However, similarly to the exemplary embodiment (fifth exemplary embodiment), the heat radiating pin  214  is cooled by the inflow wind generated between the heat radiating pins  214   
     Sixth Exemplary Embodiment 
       FIG. 18  is a view explaining an inner configuration of a light irradiating device  1 E according to a sixth exemplary embodiment of the present invention,  FIG. 18A  is a cross-sectional view of a Y-Z plane, and  FIG. 18B  is a view explaining an air flow in a part E of  FIG. 18A . 
     As illustrated in  FIGS. 18 and 16 , in the light irradiating device  1 E of the exemplary embodiment, a suction port  103   a  is formed only on the substrate  204  of a lower side panel  103  of the case  100 , which is different from the light irradiating device  1 D according to the fifth exemplary embodiment. 
     In the configuration of the exemplary embodiment, when the fans  400 A and  400 B rotate, the outside air flows from the suction port  103   a  into the case  100 . The air flowing from the suction port  103   a  flows in the case in a direction opposite to the Z-axis direction to be exhausted to the outside. Also in the configuration according to the exemplary embodiment, the air which flows from the suction port  103   a  touches the driver circuit  300 A disposed at a lower side than the cooling device  210  (a side opposite to the Y-axis direction in  FIG. 18 ). Therefore, similarly to the fifth exemplary embodiment, according to the configuration of the exemplary embodiment, not only the heat radiating pin  214 , but also the driver circuit  300 A is cooled. 
     Further, in the exemplary embodiment, the heat radiating pin  214  does not face the suction port  103   a,  so that the outside air does not flow between the heat radiating pins  214 . However, similarly to the fifth and sixth exemplary embodiments, as illustrated in  FIG. 18B , the flowed air is generated between the heat radiating pins  214 , thereby cooling the heat radiating pins  214 . 
     Seventh Exemplary Embodiment 
       FIG. 19  is a view explaining an inner configuration of a light irradiating device  1 F according to a fifth embodiment of the present invention,  FIG. 19A  is a cross-sectional view of a Y-Z plane, and  FIG. 19B  is a view explaining an air flow in a part F of  FIG. 19A . 
     As illustrated in  FIG. 19 , in the light irradiating device  1 F of the exemplary embodiment, a fan  400 F is disposed between the suction  103   a  and the heat radiating pin  214 , which is different from the light irradiating device  1 F according to the sixth exemplary embodiment. 
     In the configuration of the exemplary embodiment, when the fan  400 F rotates, the outside air flows from the suction port  103   a  into the case  100 . The air flowing from the suction port  103   a  flows in the case in a direction opposite to the Z-axis direction to be exhausted from the exhaust port  104   a  formed on the rear side panel  104  to the outside. Also in the configuration according to the exemplary embodiment, the air which flows from the suction port  103   a  touches the driver circuit  300 A disposed at a side lower than the cooling device  210 C (a direction opposite to the Y-axis direction in  FIG. 13 ). Therefore, similarly to the sixth exemplary embodiment, according to the configuration of the exemplary embodiment, the driver circuit  300 A is cooled. 
     However, as illustrated in  FIG. 19B , also in the exemplary embodiment, similarly to the fifth to seventh exemplary embodiments, when an air current in an opposing direction to the Z-axis direction is generated at a lower side of the heat radiating pin  214 , an inflow wind is generated between the heat radiating pins  214 , thereby cooling the heat radiating pins  214 . 
     The disclosed exemplary embodiments are illustrative at everything but are not restrictive. The scope of the present invention is represented not by the above description, but by claims and it is intended that all changes are included within an equivalent meaning and range with a scope of the claims. 
     EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS 
     
         
           1 ,  1 A,  1 B,  1 C,  1 D,  1 E,  1 F Light radiating device 
           100  Case 
           102  Upper side panel 
           102   a  Suction port 
           103  Lower side panel 
           103   a  Suction port 
           104  Rear side panel 
           104   a  Exhaust port 
           105  Window 
           200 A,  200 B,  200 AA,  200 BA,  200 AB,  200 BB,  200 AC,  200 BC Light source unit 
           204  Substrate 
           206  LED element 
           210  Cooling device 
           211 ,  211 A Support plate 
           212 ,  212 A Heat pipe 
           212 B Coolant flow channel 
           212   a,    212 Aa Curved part 
           212   b,    212 Ab Arm unit 
           214  Heat radiating pin 
           214 A,  214 B Corrugated pin 
           214 C Heat radiating member 
           214 Ca Pin 
           214   a  Flat part 
           214   b  Folded part 
           214   c  Through hole 
           220  Fixture 
           230 A Connecting unit 
           240 B Pump unit 
           300 A,  300 B Driver circuit 
           400 A,  400 B,  400 F Fan