Patent Publication Number: US-2018036553-A1

Title: Light irradiation device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2015-089953, filed on Apr. 27, 2015, Japanese Patent Application No. 2015-252512, filed on Dec. 24, 2015, International Patent Application No. PCT/JP2016/062531, filed on Apr. 20, 2016, the entire content of each of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a light irradiation device that emits light to irradiate the scalp or hair of a user. 
     2. Description of the Related Art 
     There has been conventionally known a hair dryer that irradiates facial skin with light of a predetermined kind for sterilization of the skin surface, for example. Patent Document 1 describes a hair dryer that provides warm air through an air outlet and comprises a light source for emitting blue light in the direction of the airflow, for example. Meanwhile, there has been studied a technique for irradiating the scalp or hair (hereinafter, referred to as scalp or the like) of a human with light of a predetermined kind in order to activate blood flow in subcutaneous tissue of the scalp and stimulate hair growth. 
     [Patent Document 1] JP2014-128524 
     The hair dryer described in Patent Document 1 includes an air inlet and an air outlet, and air drawn in through the air inlet is heated by a heater provided on an airflow passage within the body case and then blows out of the air outlet as warm air. Further, an ion generator is provided so as to provide ion-containing air, and a light source for emitting blue light in the direction of the airflow is also provided. A hair dryer of this kind includes an LED that emits blue light having a wavelength from 465 nm to 470 nm, thereby killing normal inhabitants of skin existing in the hair. The light source is provided so as to emit blue light in the direction of the airflow. The blue light provides a sterilization effect for reducing or slowing the growth of bacteria, thereby inhibiting propagation of normal inhabitants of skin in the hair irradiated with the blue light even when the hair is moisturized by ion-containing air. 
     Meanwhile, there has been studied a technique of a light irradiation device that irradiates the scalp or hair of a human with light of a predetermined kind in order to activate blood flow in subcutaneous tissue of the scalp and stimulate hair growth. Regarding such a technique, it has been found that using a certain amount of red light, which has a significant effect on subcutaneous tissue, is effective. Namely, in comparison with the light for sterilization of skin surfaces, a greater amount of light needs to be delivered to the scalp or the like in the technique. 
     In the hair dryer described in Patent Document 1, since the LED light source of blue light is provided at an end of the body case adjacent to the air outlet, the distance between the LED light source and the scalp or the like to be irradiated is longer than the distance between the air outlet and the scalp or the like. When the distance from the LED light source is longer, the amount of light delivered to the scalp or the like is reduced, which may cause a problem of difficulty in obtaining sufficient effect. 
     Also, when the distance between the LED light source and the scalp or the like is longer, the range of diffusion of the light from the LED light source becomes greater, so that the light is more likely to enter an eye. If the blue light emitted by the LED light source enters an eye, the eye may be subjected to certain stress due to the so-called blue light problem, and it cannot be said that the long-term influence exerted by such stress has been fully examined. 
     In the hair dryer described in Patent Document 1, if the emission intensity of the LED light source is raised in order to increase the amount of light delivered to the scalp or the like, the amount of light that enters an eye will also be increased. Namely, in a conventional light irradiation device, increasing the amount of light delivered to the scalp or the like is inconsistent with reducing the influence of light that enters an eye. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of such a problem, and a purpose thereof is to provide a technique of a light irradiation device for irradiating the scalp or the like of a user with light, in which the amount of light delivered to the scalp or the like can be increased while the influence of light that enters an eye is reduced. 
     To solve the problem above, a light irradiation device according to one embodiment of the present invention includes a blower unit that provides an air flow flowing in a first direction, and a light emitting unit that outputs luminous flux to irradiate a scalp or hair as an irradiation target part. The light emitting unit is provided on the first direction side of the blower unit. 
     According to the embodiment, the light emitting unit is provided forward of the blower unit in the light irradiation device for irradiating a scalp or the like, so that the light emitting unit is brought closer to the scalp or the like and an increased amount of light is delivered to the scalp, thereby reducing the relative proportion of the amount of light that enters an eye. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  is an exploded perspective view of a light irradiation device according to an embodiment; 
         FIG. 2  is a front view of the light irradiation device according to the embodiment; 
         FIG. 3  is a sectional side view of the light irradiation device according to the embodiment; 
         FIG. 4  is a front view of a cover member of the light irradiation device according to the embodiment; 
         FIG. 5  is a side view of the cover member shown in  FIG. 4 ; 
         FIG. 6  is a rear view of the cover member shown in  FIG. 4 ; 
         FIG. 7  is a magnified sectional view of the vicinity of the cover member and light emitting elements; 
         FIG. 8  is a front view of a hood member of the light irradiation device according to the embodiment; 
         FIG. 9  is a side view of the hood member shown in  FIG. 8 ; 
         FIG. 10  is a front view of a plurality of light emitting elements of the light irradiation device according to the embodiment; 
         FIG. 11  is a side view of the plurality of light emitting elements shown in  FIG. 10 ; 
         FIG. 12  is a magnified sectional view of a first engagement part and a second engagement part shown in  FIG. 3 ; 
         FIG. 13  is a block wiring diagram of the light irradiation device according to the embodiment; 
         FIG. 14  is a perspective view of a light irradiation device according to a second embodiment of the present invention; 
         FIG. 15  is a front view of the light irradiation device according to the second embodiment; 
         FIG. 16  is a sectional view taken along line A-A in  FIG. 2 ; 
         FIG. 17  is a side view that shows a state where the light irradiation device of the second embodiment is attached to a hair dryer; 
         FIGS. 18A and 18B  are sectional views that each show attachment parts shown in  FIG. 17  in detail.; 
         FIGS. 19A and 19B  are detailed sectional views that show a first modification of the attachment parts shown in  FIG. 17 ; 
         FIGS. 20A and 20B  are detailed sectional views that show a second modification of the attachment parts shown in  FIG. 17 ; 
         FIG. 21  is an illustrative diagram that shows the direction of light emitted by each LED of the light irradiation device according to the second embodiment; 
         FIG. 22  is an illustrative side view that shows the state shown in  FIG. 21  viewed from a side; 
         FIG. 23  is a sectional side view that shows an example of a mounting substrate according to the second embodiment; 
         FIG. 24  is a partial sectional side view that shows a third embodiment of the present invention; 
         FIG. 25  is an illustrative diagram that shows a fourth embodiment of the present invention and shows a state before a light irradiation device is attached to a facial roller; and 
         FIG. 26  is a side view that shows a state where the light irradiation device of the fourth embodiment is attached to a facial roller. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will now be described by reference to the preferred embodiments. This does not intend to limit the scope of the present invention, but to exemplify the invention. 
     In the following, the present invention will be described based on a preferred embodiment with reference to  FIGS. 1 through 13 . Like reference characters designate like or corresponding constituting elements and members in each drawing, and the same description therefor will be appropriately omitted. Also, the size of a member in each drawing may be appropriately enlarged or reduced in order to facilitate understanding. Further, in each drawing, part of a member less important in describing embodiments may be omitted. 
       FIG. 1  is an exploded perspective view of a light irradiation device  100  according to an embodiment,  FIG. 2  is a front view of the light irradiation device  100 , and  FIG. 3  schematically shows a side cross section of the light irradiation device  100 . In the following, description will be given based on an XYZ Cartesian coordinate system. The direction Y corresponds to a horizontal lateral direction, the direction X corresponds to a horizontal longitudinal direction, and the direction Z corresponds to a vertical direction. Each of the direction Y and the direction Z is perpendicular to the direction X. The specification may also describe the direction Y as the left direction or the right direction, the direction X as the front direction or the back direction, and the direction Z as the upward direction or the downward direction. 
     As shown in  FIG. 3 , the light irradiation device  100  according to the embodiment comprises a blower unit  40  that provides an air flow  42  flowing in a first direction P, and a light emitting unit  10  that outputs luminous flux  28  to irradiate a scalp or hair as an irradiation target part  70 , and the light emitting unit  10  is provided on the first direction P side of the blower unit  40 . 
     If the irradiation target part  70  is irradiated with the luminous flux  28  while the light irradiation device  100  is placed on the head, the temperature of the irradiation target part  70  may rise. It can be also considered that the light irradiation device  100  itself generates heat during its use and raises the temperature of the irradiation target part  70  accordingly. Therefore, the blower unit  40  in the light irradiation device  100  is configured to provide the air flow  42  toward the irradiation target part  70 . By providing the irradiation target part  70  with the air flow  42 , temperature rise can be moderated. Further, providing the irradiation target part  70  with non-heated cool air may relax the user and improve blood flow, so that synergistic effect with the luminous flux  28  provided to the scalp can also be expected. 
     (Cover Member) 
     There will now be descried a cover member  18  with reference to  FIGS. 4 through 6 .  FIG. 4  is a front view of the cover member  18 ,  FIG. 5  is a side view thereof, and  FIG. 6  is a rear view thereof. 
     If multiple light emitting elements  20  are brought into direct contact with the scalp or hair as the irradiation target part  70 , foreign matter, such as sebum, may adhere to the multiple light emitting elements  20 , of which the surfaces may be blurred accordingly. If the surfaces of the multiple light emitting elements  20  are blurred, the amount of light to be output could be reduced. Accordingly, it is desirable that the multiple light emitting elements  20  are not brought into direct contact with the irradiation target part  70 . Therefore, in the light emitting unit  10  of the light irradiation device  100 , the cover member  18 , which transmits the luminous flux  28 , is replaceably provided. If foreign matter adheres to the cover member  18 , the cover member  18  can be detached to be washed. The cover member  18  may be provided with an engagement part, so as to be easily attached and detached. 
     (Projections) 
     If the front surface of the cover member is flat, hair pressed by the cover member will be dense, so that the proportion of luminous flux striking the hair would be increased, whereas the proportion thereof delivered to the scalp would be reduced. Therefore, the cover member  18  of the light irradiation device  100  includes multiple projections  19  that project in the first direction P. Accordingly, the projections  19  thrust through the hair and the tips of the projections  19  come close to the scalp, so that the luminous flux  28  can be efficiently delivered to the scalp. Also, the tips of the projections  19  touching the scalp would provide moderate stimulation to the scalp, thereby stimulating blood flow. 
     In order to prevent increase in size, the dimension in a longitudinal direction of the light emitting unit may desirably be small. Accordingly, in the light irradiation device  100 , the cover member  18  is provided with recesses  19   b  that respectively house at least part of the multiple light emitting elements  20 , as shown in  FIG. 7 . For example, by allowing the recesses  19   b  to house the tips of the light emitting elements  20 , the dimension in a longitudinal direction of the light emitting unit  10  can be reduced. The recesses  19   b  may be provided so as to correspond to the projections  19 . 
     It is desirable that the luminous flux  28  contains less ultraviolet light, which is harmful. Therefore, the cover member  18  of the light irradiation device  100  is formed of a material that attenuates ultraviolet light. Accordingly, since the luminous flux  28  that has penetrated the cover member  18  contains less ultraviolet light, the user can safely use the light irradiation device  100 . 
     Since a human head has a substantially spherical shape, the irradiation target part may be often curved. Accordingly, the shape of the cover member may desirably be set to follow the curved shape of the irradiation target part. Therefore, the cover member  18  of the light irradiation device  100  includes a receding region  18   a  that is receding toward the blower unit  40  along the longitudinal direction of the first direction P, and a projecting region  18   b  that is projecting forward of the receding region  18   a  in the first direction P, as shown in  FIG. 5 . Accordingly, the receding region  18   a  and the projecting region  18   b  of the cover member  18  can be arranged so as to follow a curved shape C of an irradiation target part  70 . 
     (Hood Member) 
     Next, a hood member  15  will be described with reference to  FIGS. 8 and 9 .  FIG. 8  is a front view of the hood member  15 , and  FIG. 9  is a side view thereof. 
     If part of the luminous flux  28  leaks outside, the leaked light may enter an eye. Therefore, the light emitting unit  10  of the light irradiation device  100  comprises the hood member  15  that surrounds the luminous flux  28  on the first direction P side. With the hood member  15 , the amount of light that leaks outside can be reduced. By setting the hood member  15  to be contactable with the irradiation target part  70 , the amount of light that leaks outside can be further reduced. The hood member  15  may be provided so as to extend forward of the projections  19  of the cover member  18 . The hood member  15  includes a receding region  15   a  corresponding to the receding region  18   a  of the cover member  18 , and a projecting region  15   b  corresponding to the projecting region  18   b  of the cover member  18 . The projecting region  15   b  is positioned forward of the receding region  15   a  in the first direction P. 
     There will now be described the multiple light emitting elements  20  with reference to  FIGS. 10 and 11 .  FIG. 10  is a front view of the multiple light emitting elements  20  attached to a substrate  13 , and  FIG. 11  is a side view thereof. 
     In terms of users&#39; convenience, the light irradiation device may desirably be capable of emitting luminous flux in a wider range. Accordingly, the light emitting unit  10  of the light irradiation device  100  includes the multiple light emitting elements  20 , as shown in  FIG. 10 . As the multiple light emitting elements  20 , light emitting diodes (LEDs) or laser diodes (LDs) may be used, for example. In the light irradiation device  100 , the multiple light emitting elements  20  are arranged so as to surround the air flow  42 . The multiple light emitting elements  20  may be arranged in a circular, an oval, or a polygonal shape to surround the air flow  42 . 
     As stated previously, since a human head has a substantially spherical shape, the irradiation target part may be often curved. Accordingly, the position of each of the light emitting elements may desirably be set to follow the curved shape of the irradiation target part. Therefore, the multiple light emitting elements  20  of the light irradiation device  100  include light emitting elements  20   a  that are receding toward the blower unit along the longitudinal direction of the first direction P, and light emitting elements  20   b  that are projecting forward of the receding light emitting elements  20   a  in the first direction, as shown in  FIG. 11 . Namely, in the light irradiation device  100 , the position in the longitudinal direction of each of the multiple light emitting elements  20  is adjusted so as to follow a curved shape C of a head. In the light irradiation device  100 , as an example, along the direction Z (vertical direction), light emitting elements  20   a  near the center are arranged to recede along the longitudinal direction of the first direction P backward of light emitting elements  20   b  on the both sides (upper side and lower side). Accordingly, differences in distance from the surface of a head among the multiple light emitting elements  20  become smaller, so that the luminous flux  28  can be effectively provided. 
     The amount of light received at each region of the irradiation target part may desirably be less different from each other. Accordingly, in the light irradiation device  100 , at least part of the multiple light emitting elements  20  are provided to be inclined with respect to the longitudinal direction of the first direction P. Namely, at least part of the multiple light emitting elements  20  of the light irradiation device  100  are provided so that the optical axes thereof are inclined with respect to the longitudinal direction. In the light irradiation device  100 , as an example, the multiple light emitting elements  20  are inclined inward so that the optical axes thereof intersect in front. Alternatively, the multiple light emitting elements  20  may be inclined outward so that the optical axes thereof are directed away from each other in front. The direction of the inclination may be set according to the directivity of the light emitting element. The inclination may be set within the range of 3 to 30 degrees, for example. In the light irradiation device  100 , the multiple light emitting elements  20  are provided so that the optical axes thereof are inclined at 3 degrees inward with respect to the longitudinal direction. 
     When luminous flux with a greater amount of light is output, temperature rise may occur in the light emitting elements of the light emitting unit or electronic components therearound. If the operating temperature is higher, the life of the light emitting elements and electronic components will be shortened, so that it is desirable to use the light emitting elements and the electronic components therearound while cooling them. Accordingly, in the light irradiation device  100 , at least part of the multiple light emitting elements  20  are arranged in a region where the air flow  42  passes through, as shown in  FIG. 3 . Namely, the multiple light emitting elements  20  are arranged in a range extending forward from an air outlet  114 . In this case, the multiple light emitting elements  20  are cooled by the air flow  42  provided through the air outlet  114 , so that temperature rise can be prevented. 
     Also, in the light emitting unit  10  of the light irradiation device  100 , at least part of electronic components  14 , each electrically connected to one of the multiple light emitting elements  20 , are arranged in a range where the air flow  42  passes through, as shown in  FIG. 3 . Namely, at least part of the electronic components  14  are arranged so that heat dissipation is promoted by the air flow  42 . Accordingly, the electronic components  14  are exposed to the air flow  42  and cooled thereby, so that temperature rise can be prevented. 
     It is desirable to reduce the possibility that the luminous flux  28  output by the light emitting unit  10  will enter an eye. Accordingly, as shown in  FIG. 3 , the light irradiation device  100  comprises a current limiting unit  32  configured to shut off or reduce the current supplied to the light emitting unit  10  when the light emitting unit  10  is apart from the irradiation target part  70  by a predetermined distance or more. Namely, the light irradiation device  100  is configured so that, when the light emitting unit  10  is close to the irradiation target part  70 , the light emitting unit  10  is energized and outputs the luminous flux  28 , and, when the light emitting unit  10  is distanced from the irradiation target part  70 , the energization is substantially stopped. For example, the current limiting unit  32  may be configured to detect the distance from the light emitting unit  10  and control energization of the light emitting unit  10  according to the detected distance. Also, the current limiting unit  32  may be configured to energize the light emitting unit  10  when the light emitting unit  10  is brought into contact with the irradiation target part  70  or the vicinity thereof. Accordingly, when the light emitting unit  10  is distanced from the head, the output of the luminous flux  28  is automatically decreased, thereby reducing the possibility that the luminous flux  28  enters an eye. In order to facilitate understanding, illustration of the current limiting unit  32  is omitted in  FIGS. 1 and 2 . 
     (Sign Output Unit) 
     For example, a head may be separated into multiple irradiation target parts, and the light irradiation device may be used for each of the irradiation target parts for a predetermined period of time. In terms of usability, the operating time for each of the irradiation target parts may be suitably set within the range of 3 to 30 seconds, and more suitably set within the range of 5 to 20 seconds. The operating time for each of the irradiation target parts will be shorter when the luminous flux from the light irradiation device is larger, and will be longer when the luminous flux is smaller. It will be convenient for a user if a sign for the operating time is output. Accordingly, as shown in  FIG. 3 , the light irradiation device  100  comprises a sign output unit  34  configured to output a sign that can be perceived by a user at predetermined timing. As an example, the sign output unit may be configured to output a beep  34   e  as a sign every preset time (10 seconds, for example). Accordingly, the user can change the irradiation position at the timing of the sign during use. The sign is not particularly limited, as long as it can be perceived by users. In order to facilitate understanding, illustration of the sign output unit  34  is omitted in  FIGS. 1 and 2 . 
     The operating time for each of the irradiation target parts may desirably be constant. Accordingly, in the light irradiation device  100 , the sign output unit  34  is configured to output a sign using at least one of sound, vibration, and light, at timing when a predetermined period of time elapses after the supply of a current to the light emitting unit  10  is started. As an example, the sign output unit  34  may be configured to output the beep  34   e  as a sign, at timing when a preset time (5 seconds, for example) elapses after the supply of a current to the light emitting unit  10  is started. Accordingly, the user can change the irradiation position at the timing of the beep  34   e  during use. In this case, the operating time for each of the irradiation target parts is likely to be constant. 
     If the light irradiation device can be decomposed into blocks, it can be compactly stored and will be convenient for carrying. Meanwhile, it is desirable that, only by supplying power to one of the light emitting unit and the blower unit, the other can also be supplied with power in the light irradiation device. Accordingly, in the light irradiation device  100 , the light emitting unit  10  is provided to be attachable to and detachable from the blower unit  40 , the blower unit  40  includes a first contact part  36  used to supply a current to the light emitting unit  10 , and the light emitting unit  10  includes a second contact part  38  that is electrically connected to the first contact part  36  when the light emitting unit  10  is attached to the blower unit  40 . With such a configuration, the light irradiation device  100  can be decomposed into the light emitting unit  10  and the blower unit  40  to be stored. Also, by attaching the light emitting unit  10  to the blower unit  40  and supplying power only to the blower unit  40  in the light irradiation device  100 , the light emitting unit  10  can also be supplied with power via the first contact part  36  and the second contact part  38 . 
     There will now be described the specific structure of the light irradiation device  100 . 
     (Blower Unit) 
     As shown in  FIG. 3 , the blower unit  40  comprises a casing  110 , a grip portion  108 , an air inlet  116 , the air outlet  114 , an impeller  43 , a motor  41 , a heater  44 , a control unit  50 , a switch unit  52 , a wiring passage unit  118 , the first contact part  36 , a power supply unit  124 , and a first engagement part  82 . 
     The casing  110  is a housing that houses and retains therein the main constituting elements of the blower unit  40 . The casing  110  is a hollow and substantially-cylindrical member, which can be formed of a resin material through a molding process. The grip portion  108  is a part held by a user with a hand and attached so as to protrude downward from the lower surface of the outer periphery of the casing  110  near the rear side. The grip portion  108  may be connected to the casing  110  via a hinge means for enabling folding. 
     The air inlet  116  is an opening through which air to be provided is introduced from the surrounding space into the casing  110 , and may be provided on the rear side of the casing  110 , for example. The air inlet  116  may be provided with a mesh member (not illustrated) to inhibit entry of foreign matter. The air outlet  114  is an opening through which the air flow  42  comes out and provided on the front side of the casing  110 . The air outlet  114  may also be provided with a mesh member (not illustrated) to inhibit entry of foreign matter. 
     The impeller  43  is a blade member that rotates to push air at the back toward the front, and can be formed of a resin material through a molding process, for example. The impeller  43  is disposed in front of the air inlet  116  within the casing  110 . The motor  41  is an electric motor for rotating the impeller  43  and rotates with a current supplied from the control unit  50 . The motor  41  is disposed in front of the impeller  43  within the casing  110 , and the rotating shaft (not illustrated) of the motor  41  is fixed to the center of the impeller  43 . 
     The heater  44  is an electric heater for heating the air flow pushed out by the impeller  43 , and generates heat with a current supplied from the control unit  50 . The heater  44  is disposed in front of the motor  41  within the casing  110 . The control unit  50  is configured to control electric power supplied from the power supply unit  124  and supply a current to each of the motor  41 , heater  44 , and light emitting unit  10  according to the state of the switch unit  52 . The control unit  50  may be housed and fixed within the grip portion  108 , for example. Also, the control unit  50  may be housed within the casing  110 . In order to restrict excessive irradiation for the irradiation target part  70 , there may be provided a means for limiting the amount of light emitted by the light emitting unit  10 . As an example, the control unit  50  may be configured to limit power supply to the light emitting unit  10 , based on a value obtained through a predetermined calculation using, as parameters, a current supplied to the light emitting unit  10  and the time for which the current is supplied. 
     The switch unit  52  is a member for switching the operation mode of the light irradiation device  100 . The switch unit  52  may include a mechanical switch having a mechanical contact, and an electronic switch that detects a finger touch and electronically switches the operation mode. The switch unit  52  is attached to the grip portion  108  so that a protruding part  52   a  protrudes from an opening  108   a  provided on the front side of the grip portion  108 . The switch unit  52  is configured to switch the operation mode among multiple modes when the protruding part  52   a  is pressed backward. For example, starting from the all-off state, the first press of the protruding part  52   a  may supply a current to the motor  41  so as to start to provide air, the second press may supply a current to the light emitting unit  10  so as to start light emission, the third press may stop the current supply to the light emitting unit  10  and supply a current to the heater  44  so as to start heating, and the fourth press may place the light irradiation device  100  in the all-off state again. The switch unit  52  may include multiple electrical switches. Also, the switch unit  52  may include a light emission control switch used to start or stop power supply to the light emitting unit  10 , and the light emission control switch may be configured to start or stop the power supply according to the orientation of the light irradiation device  100 . As an example, the light emission control switch may be configured to start power supply to the light emitting unit  10  when the orientation of the light irradiation device  100  is set to a predetermined orientation (such as an orientation in which the light emitting unit  10  faces a head). 
     The first contact part  36  has a contact to be electrically connected to the second contact part  38  and is electrically connected to an output part of the control unit  50  via an electric cable  126 . The first contact part  36  may be provided on the outer periphery of the first engagement part  82 , for example. The wiring passage unit  118  is a passage for protecting the electric cable  126 , which connects the control unit  50  and the light emitting unit  10 , from the heat generated by the heater  44 . Particularly, in order to house the electric cable  126  connecting the control unit  50  and the first contact part  36 , the wiring passage unit  118  is provided on the lower part of the casing  110 . 
     The power supply unit  124  is an electrical circuit for providing electric power supplied through a power supply cable (not illustrate) to the control unit  50 , and is housed and fixed within the grip portion  108 . The power supply unit  124  may include a rectifier circuit and a smoothing circuit. 
       FIG. 12  is a magnified sectional view of the first engagement part  82  and a second engagement part  84 , which will be described later. The first engagement part  82  is an attaching/detaching mechanism with which the light emitting unit  10  is detachably mounted to the blower unit  40 . The first engagement part  82  includes a fitting outer surface  82   a  provided on the front part of the casing  110 , and a click part  82   b  provided on the fitting outer surface  82   a.  The fitting outer surface  82   a  may be formed to have a diameter smaller than that of a region in the rear of the fitting outer surface  82   a,  for example. On the fitting outer surface  82   a,  one or multiple (two, for example) click parts  82   b  may be provided. The fitting outer surface  82   a  is configured to fit to a fitting inner surface  84   a  of the second engagement part  84 . The click part  82   b  is configured to engage with a step part  84   b  of the second engagement part  84 . 
     (Light Emitting Unit) 
     As shown in  FIG. 3 , the light emitting unit  10  comprises a housing  30 , a vent hole  86 , the cover member  18 , hood member  15 , substrate  13 , electronic components  14 , multiple light emitting elements  20 , second contact part  38 , and second engagement part  84 . 
     The housing  30  is a hollow and substantially-cylindrical member that houses and retains therein the main constituting elements of the light emitting unit  10 . The housing  30  may be formed of a resin material through a molding process, for example. The vent hole  86  is an opening that communicates the inside and the outside of the housing  30 , and one or multiple (four, for example) vent holes  86  are formed on the outer periphery of the housing  30 . The vent hole  86  can promote air ventilation within the housing  30 , thereby preventing temperature rise in the irradiation target part  70 . 
     The cover member  18  is a substantially-discoid member provided perpendicularly to a longitudinal direction (direction X) and includes an inner periphery  18   j  and an outer periphery  18   k,  as shown in  FIGS. 4-7 . The cover member  18  may be formed of a resin material having favorable light transmission properties through a molding process, for example. On the front side of the cover member  18 , multiple (24, for example) projections  19 , which project forward, are provided. Each of the projections  19  has a shell-like shape, such as a cylinder with a hemisphere connected to an end thereof. As shown in  FIG. 6 , on the back side of the cover member  18 , multiple (24, for example) recesses  19   b,  which are recessed forward, are provided. The recesses  19   b  house the tips of the multiple light emitting elements  20 . The recesses  19   b  are provided so as to correspond to the projections  19 . 
     The hood member  15  is a hollow cylindrical member extending in a longitudinal direction (direction X) and includes an inner periphery  15   j  and an outer periphery  15   k,  as shown in  FIGS. 8 and 9 . The hood member  15  may be formed of a resin material through a molding process, for example. The hood member  15  may be formed of a material having low light transmission properties. On the inner surface of the hood member  15 , a reflecting surface may be formed. Further, the hood member  15  may be formed integrally with the cover member  18  so as to be attachable to and detachable from the light emitting unit  10 . 
     The substrate  13  is a printed wiring board of a substantially-discoid shape provided perpendicularly to a longitudinal direction and includes an inner periphery  13   j  and an outer periphery  13   k,  as shown in  FIGS. 10 and 11 . The outer periphery  13   k  of the substrate  13  is fixed to a step part of the housing  30  by screwing or bonding. The electronic components  14  may include a resistor for limiting a current flowing through the multiple light emitting elements  20 , or a capacitor for smoothing a voltage. The electronic components  14  are fixed to the front side or the back side of the substrate  13  by soldering, for example. 
     As shown in  FIGS. 10 and 11 , the multiple light emitting elements  20  include multiple ( 24 , for example) LEDs  20   m  that are provided on the front side of the substrate  13  to be substantially evenly spaced in a circumferential direction. Although the LEDs  20   m  are not particularly limited, in the light irradiation device  100  of the embodiment, LEDs that emit light with a wavelength from 620 nm to 670 nm (red) are employed. For example, it has been found that using red light of 638 nm with an amount of 1-1.5 J/cm 2  is effective for activation of subcutaneous tissue. 
     The second contact part  38  has a contact to be electrically connected to the first contact part  36  and is electrically connected to the multiple light emitting elements  20  via an electric cable  128 , as shown in  FIG. 13 . The second contact part  38  may be provided on the inner periphery of the second engagement part  84 , for example. When the light emitting unit  10  is attached to the blower unit  40 , the two contacts of the second contact part  38  are electrically connected to the two contacts of the first contact part  36 , respectively. 
     As shown in  FIG. 12 , the second engagement part  84  is an attaching/detaching mechanism with which the light emitting unit  10  is detachably mounted to the blower unit  40 . The second engagement part  84  includes the fitting inner surface  84   a  provided on the rear part of the housing  30 , and the step part  84   b  formed on the fitting inner surface  84   a.  On the fitting inner surface  84   a,  one or multiple (two, for example) step parts  84   b  may be provided. The fitting inner surface  84   a  is configured to fit to the fitting outer surface  82   a  of the first engagement part  82 . The step part  84   b  is configured to engage with the click part  82   b  of the first engagement part  82 . 
     (Current Limiting Unit) 
     The current limiting unit  32  is configured to shut off or reduce the current supplied to the light emitting unit  10  when the light emitting unit  10  is apart from the irradiation target part  70  by a predetermined distance or more. The current limiting unit  32  includes a sensor unit  32   a  and is configured to shut off or reduce the current supplied to the light emitting unit  10  according to the state of the sensor unit  32   a.  For the sensor unit  32   a,  a limit switch, of which the output state is changed according to mechanical contact, or a distance sensor using light or sound waves may be employed. In the light irradiation device  100  of the embodiment, the sensor unit  32   a  is attached to the outer periphery of the housing  30 , as shown in  FIG. 3 . The sensor unit  32   a  includes a tip part  32   e  protruding forward on the front part and also contains a limit switch  32   b  that is turned on when the tip part  32   e  is brought into contact with an irradiation target part  70  and is pressed into the sensor unit  32   a.  As shown in  FIG. 13 , the limit switch  32   b,  connected in series to the light emitting unit  10 , is turned off when the light irradiation device  100  is not used, and is turned on when the tip part  32   e  is brought into contact with an irradiation target part  70 , so that the light emitting unit  10  is energized. By adjusting the position of the tip part  32   e,  the distance for switching energization and non-energization can be set to a desired distance. 
     (Sign Output Unit) 
     The sign output unit  34  is configured to output a sign using at least one of sound, vibration, and light, at predetermined timing. The sign output unit  34  is provided in the light emitting unit  10  or the blower unit  40 . In the light irradiation device  100 , the sign output unit  34  is provided on the outer periphery of the housing  30 , as shown in  FIG. 3 . In the light irradiation device  100  of the embodiment, the sign output unit  34  is configured to output a sign at timing when a predetermined period of time elapses after the supply of a current to the light emitting unit  10  is started. As shown in the block wiring diagram of  FIG. 13 , the sign output unit  34  includes a timer means  34   a,  of which the output state is changed from OFF to ON when a preset period of time elapses after the energization of the light emitting unit  10  is started, and a buzzer means  34   b,  which generates the beep  34   e  when the output state of the timer means  34   a  is ON. When the light emitting unit  10  is energized, the timer means  34   a  is activated and starts time counting. After the timer means  34   a  performs time counting for a predetermined period of time, the buzzer means  34   b  is energized to generate the beep  34   e.  When the light emitting unit  10  is not energized, the timer means  34   a  is reset and the buzzer means  34   b  is stopped. When the light emitting unit  10  is energized again, the timer means  34   a  is activated, and the sign output unit  34  repeats the operations described above. 
     There will now be described a method for using the light irradiation device  100  configured as set forth above. 
     (1) First Use Mode 
     In the first use mode, the blower unit  40  is not operated, and only the light emitting function of the light emitting unit  10  is used. This mode will be referred to as the first mode. First, the switch unit  52  is operated to place the light irradiation device  100  in the first mode. In this state, the current limiting unit  32  is operated, and the light emitting unit  10  does not emit light. When the light emitting unit  10  is brought closer to a head and the tip part  32   e  comes into contact with an irradiation target part  70 , the light emitting unit  10  is energized and starts light emission to irradiate the irradiation target part  70  with the luminous flux  28 . Concurrently, the timer means  34   a  is activated and, when 10 seconds as preset elapses, for example, the buzzer means  34   b  generates the beep  34   e.  In response to the beep  34   e,  the user will once move the light emitting unit  10  away from the head. In this state, the light emission and the beep  34   e  is stopped. If the user places the light emitting unit  10  close to an irradiation target part  70  at another position of the head, and the tip part  32   e  comes into contact with the irradiation target part  70 , the same operations as stated above will be repeated. With such repetitive operations, the luminous flux  28  can be provided to a desired range of the head. 
     (2) Second Use Mode 
     In the second use mode, the blower unit  40  is placed in the state of supplying non-heated cool air and used with the light emitting function of the light emitting unit  10 . This mode will be referred to as the second mode. First, the switch unit  52  is operated to place the light irradiation device  100  in the second mode. In this state, a non-heated air flow  42  provided by the blower unit  40  passes through a center hole part  16  of the light emitting unit  10  and then blows out of an outlet  16   b.  When the light emitting unit  10  is brought close to a head, the head receives the air flow  42 . Further, when the light emitting unit  10  is brought closer to the head, and the tip part  32   e  comes into contact with an irradiation target part  70 , the light emitting unit  10  is energized and starts light emission to irradiate the irradiation target part  70  with the luminous flux  28 . Thus, in this state, the irradiation target part  70  receives the non-heated air flow  42  and the luminous flux  28  at the same time. As with in the first use mode, the sign output unit  34  is operated, and the beep  34   e  is generated at predetermined timing. In response to the beep  34   e,  the user will place the light emitting unit  10  on an irradiation target part  70  at another position of the head, and the same operations as stated above will be repeated. With such repetitive operations, the user can receive the non-heated air flow  42  and the luminous flux  28  at the same time on a desired range of the head. 
     (3) Third Use Mode 
     In the third use mode, the blower unit  40  is placed in the state of supplying heated warm air and used with the light emitting function of the light emitting unit  10 . This mode will be referred to as the third mode. First, the switch unit  52  is operated to place the light irradiation device  100  in the third mode. In this state, a heated air flow  42  provided by the blower unit  40  passes through the center hole part  16  of the light emitting unit  10  and then blows out of the outlet  16   b.  The operations thereafter are the same as those in the second use mode, and, by repeating the operations, the heated air flow  42  and the luminous flux  28  can be provided at the same time to a desired range of the head. 
     (4) Fourth Use Mode 
     In the fourth use mode, the light emitting unit  10  is not operated, and only the blower function of the blower unit  40  is used. In this case, the light emitting unit  10  may be detached from the blower unit  40 , or may be attached to the blower unit  40 . In the following, an example of using the light irradiation device  100  with the light emitting unit  10  attached to the blower unit  40  will be described. This mode will be referred to as the fourth mode. First, the switch unit  52  is operated to place the light irradiation device  100  in the fourth mode. In this state, a non-heated or heated air flow  42  provided by the blower unit  40  passes through the center hole part  16  of the light emitting unit  10  and then blows out of the outlet  16   b.  According to the fourth use mode, the user can receive the non-heated or heated air flow  42  on a desired range of the head. In the fourth use mode, the sign output unit  34  may be used, or may be not used. 
     The light irradiation device  100  may be used in the state where at least part of the front part, i.e., the first direction P side, of the light emitting unit  10  is in contact with a head. Particularly, in the first through the third use modes above, the light irradiation device  100  may be used while it is partly in contact with a head. By using the light irradiation device  100  in this way, the amount of light that leaks outside can be reduced. 
     There will now be described the features of the light irradiation device  100  according to the embodiment of the present invention. 
     The light irradiation device  100  comprises the blower unit  40  that provides an air flow  42  flowing in the first direction P, and the light emitting unit  10  that outputs the luminous flux  28  to irradiate a scalp or hair as an irradiation target part  70 , and the light emitting unit  10  is provided on the first direction P side of the blower unit  40 . With such a configuration, the irradiation target part  70  can receive the luminous flux  28  from the light irradiation device  100 . 
     The blower unit  40  in the light irradiation device  100  is configured to provide the air flow  42  toward the irradiation target part  70 , which can receive the air flow  42  together with the luminous flux  28  accordingly. 
     In the light emitting unit  10  of the light irradiation device  100 , the cover member  18 , which transmits the luminous flux  28 , is replaceably provided, thereby reducing the possibility that the multiple light emitting elements  20  are brought into direct contact with the irradiation target part  70 . 
     In the light irradiation device  100 , the cover member  18  includes the multiple projections  19  that project in the first direction P, and the projections  19  thrust through hair and can moderate density of the hair. Also, in the light irradiation device  100 , the cover member  18  is provided with the recesses  19   b  that respectively house at least part of the multiple light emitting elements  20 , so that the tips of the light emitting elements  20  can be housed by the recesses  19   b.  Also, since the cover member  18  of the light irradiation device  100  is formed of a material that attenuates ultraviolet light, the cover member  18  can attenuate ultraviolet light in the luminous flux  28 . 
     In the light irradiation device  100 , since the cover member  18  includes the receding region  18   a,  which is receding toward the blower unit  40  along the longitudinal direction of the first direction P, and the projecting region  18   b,  which is projecting forward of the receding region  18   a  in the first direction P, the cover member  18  can follow a curved shape of an irradiation target part  70 . 
     The light emitting unit  10  of the light irradiation device  100  comprises the hood member  15  that surrounds the luminous flux  28  on the first direction P side, and the hood member  15  can cover the luminous flux  28 . 
     The light emitting unit  10  of the light irradiation device  100  comprises the multiple light emitting elements  20 , so that the light emitting unit  10  can emit light with the multiple light emitting elements  20 . 
     In the light irradiation device  100 , since the multiple light emitting elements  20  include the light emitting elements  20   a,  which are receding toward the blower unit along the longitudinal direction of the first direction P, and the light emitting elements  20   b,  which are projecting forward of the receding light emitting elements  20   a  in the first direction, the multiple light emitting elements  20  can follow a curved shape of an irradiation target part  70 . 
     In the light irradiation device  100 , at least part of the multiple light emitting elements  20  are provided to be inclined with respect to the longitudinal direction of the first direction P, so that the multiple light emitting elements  20  can include light emitting elements inclined from the first direction P. 
     In the light irradiation device  100 , at least part of the multiple light emitting elements  20  are arranged in a region where the air flow  42  passes through, so that the multiple light emitting elements  20  can include light emitting elements arranged in a region where the air flow  42  passes through. 
     In the light emitting unit  10  of the light irradiation device  100 , at least part of the electronic components  14 , each electrically connected to one of the multiple light emitting elements  20 , are arranged in a range where the air flow  42  passes through, so that the light emitting unit  10  can include electronic components arranged in a region where the air flow  42  passes through. 
     Since the light irradiation device  100  comprises the current limiting unit  32  configured to shut off or reduce the current supplied to the light emitting unit  10  when the light emitting unit  10  is apart from the irradiation target part  70  by a predetermined distance or more, the current at the light emitting unit  10  can be changed when the light emitting unit  10  is apart from the irradiation target part  70 . 
     Since the light irradiation device  100  comprises the sign output unit  34  configured to output a sign that can be perceived by a user at predetermined timing, the user can perceive the predetermined timing with the sign. 
     In the light irradiation device  100 , since the sign output unit  34  is configured to output a sign using at least one of sound, vibration, and light, at timing when a predetermined period of time elapses after the supply of a current to the light emitting unit  10  is started, the user can perceive the timing when the predetermined period of time elapses, with the at least one of sound, vibration, and light. 
     In the light irradiation device  100 , since the light emitting unit  10  is provided to be attachable to and detachable from the blower unit  40 , the blower unit  40  includes the first contact part  36  used to supply a current to the light emitting unit  10 , and the light emitting unit  10  includes the second contact part  38  that is electrically connected to the first contact part  36  when the light emitting unit  10  is attached to the blower unit  40 , the light emitting unit  10  of the light irradiation device  100  can be detached. 
     The present invention has been described with reference to the embodiment. The embodiment is intended to be illustrative only, and it will be obvious to those skilled in the art that various modifications and changes could be developed within the scope of claims of the present invention and that such modifications and changes also fall within the scope of claims of the present invention. Therefore, the description in the present specification and the drawings should be regarded as exemplary rather than limitative. 
     (First Modification) 
     Although there has been described an example in which LEDs outputting red light are used in the light irradiation device  100 , the application is not limited thereto. For example, LEDs outputting green light or blue light may be used, or LEDs outputting light of assorted colors may be used in combination. 
     (Second Modification) 
     Although there has been described an example in which LEDs or LDs are used as the light emitting elements in the light irradiation device  100 , the application is not limited thereto. For example, organic EL elements or other kinds of light emitting elements may also be used. 
     (Third Modification) 
     The light irradiation device of the present invention may be provided with a means for providing air containing negative ions, or a means for providing a mist obtained by atomizing liquid, such as water and beauty essence. 
     In the following, light irradiation devices  210 ,  220 , and  230  according to the second through fourth embodiments of the present invention will be described. In recent years, it has been found that light emitted by a light emitting diode (an LED) improves cell activity, has no side effects on cell activity, increases fibroblasts, produces a growth factor, produces collagen, and increases vascularization. Further, it has been found that LED irradiation is effective for healing of skin tissue or hair. 
     On the basis of such findings, the light irradiation devices  210 ,  220 , and  230  according to the second through fourth embodiments of the present invention are proposed. Each of the light irradiation devices  210 ,  220 , and  230  comprises multiple light emitting diodes ( 1 A: hereinafter, referred to as “LEDs” in this specification) and can be attached to and detached from cosmetic appliances  180  and  280 . 
     The LEDs may suitably emit one of or all of light with a wavelength from 620 nm to 670 nm (red), light with a wavelength from 450 nm to 480 nm (blue), light with a wavelength from 560 nm to 600 nm (yellow), and light with a wavelength from 500 nm to 530 nm (green), for example. 
     The term “cosmetic appliance” used in the present specification has meanings including a hair dryer for arranging a hairstyle, and a facial appliance (such as a facial roller and each of other various facial devices) for activating facial skin to create so-called “beautiful skin”. 
     In the second through the fourth embodiments of the present invention, it is suitable that the multiple LEDs  1 A are arranged in a closed shape formed by a curve (such as a circle and an ellipse), and light emitted by each of the LEDs  1 A travels in a direction inclined toward the inner region of the shape. 
     Also, in the second through the fourth embodiments of the present invention, there is provided a spray device  215  that can be attached to and detached from the light irradiation device  220 , and the spray device  215  may suitably include a liquid storage unit  15 A, and a spray unit  15 B that sprays a mist of liquid (such as liquid for so-called “beautiful hair”) stored in the liquid storage unit  15 A. 
     The cosmetic appliance  180  may suitably be a hair dryer. 
     The cosmetic appliance  280  may suitably be a facial appliance (such as a facial roller and each of other various facial devices). 
     With the abovementioned configuration, in the case of a hair dryer, in addition to warm air or cool air, light emitted by the multiple LEDs  1 A provided in the light irradiation device  210 ,  220 , or  230  is delivered to the scalp of a user, thereby improving cell activity, increasing fibroblasts, producing a growth factor, producing collagen, and increasing vascularization in the user&#39;s scalp, so as to exert a favorable influence on the skin tissue and hair and to place the scalp in favorable condition. Also, since each of the light irradiation devices  210 ,  220 , and  230  is configured to be attachable to and detachable from the cosmetic appliances  180  and  280 , the light irradiation devices  210 ,  220 , and  230  that can be attached to a conventional hair dryer or the like can be easily produced. Therefore, the present invention is applicable without significantly modifying a conventional hair dryer or the like. 
     Further, the multiple LEDs  1 A provided in the light irradiation devices  210 ,  220 , and  230  are arranged in a circle (including an ellipse) and, if the light irradiation devices  210 ,  220 , and  230  are configured so that light emitted by each of the LEDs  1 A travels in a direction inclined radially inward of the circle, light emitted by the LEDs  1 A will not reach an eye of a user of the cosmetic appliances  180  and  280  according to the present invention. This prevents the light emitted by the LEDs damaging the user&#39;s eyes. 
     In addition, when the spray device  215  is provided so as to be attachable to and detachable from the light irradiation device  220 , and the spray device  215  is configured to include a spray unit that sprays a mist of liquid (such as liquid for so-called “beautiful hair”) in the present invention, there can be obtained the effect of favorable hair condition due to the spraying of the liquid for beautiful hair, in addition to the effects of setting a hairstyle using warm air or cool air and the activation of the scalp by LED irradiation. 
     The present invention is applicable not only to a hair dryer but also to a facial appliance (such as a facial roller and each of other various facial devices). 
     There will now be described the light irradiation device  210  according to the second embodiment of the present invention, with reference to  FIGS. 14-23 . In the second embodiment, a hair dryer is used as an example of a cosmetic appliance. In  FIGS. 14 and 15 , the light irradiation device  210  comprises a casing unit  2  of a substantially cylindrical shape formed of a synthetic resin material having electrical insulating properties, and an LED unit  1  including the multiple LEDs  1 A arranged in a circular shape and provided on the front end (left side in  FIG. 1 ) of the casing unit  2 . 
     As shown in  FIG. 16 , to the front end (left end part in  FIG. 14 ) of the casing unit  2 , a cover  3  of a ring shape formed of a transparent synthetic resin material is attached, and the multiple LEDs  1 A are covered with the cover  3 . As will be described later with reference to  FIG. 16 , the LED unit  1  comprises the multiple LEDs  1 A and a member for attaching the LEDs  1 A to the front end of the casing unit  2 . 
     The detailed configuration of the LED unit  1  will be described with reference to  FIGS. 15 and 16 . In  FIG. 16 , the multiple LEDs  1 A are provided on a mounting substrate  1 C via the respective energization terminals  1 B, and, between the LEDs  1 A and the mounting substrate  1 C, a thermal insulation board, not illustrated, is interposed. Each of the mounting substrate  1 C, the thermal insulation board (not illustrated), and a supporting member  1 D, which will be described later, is a ring-shaped plate, and the multiple LEDs  1 A are substantially evenly spaced upon the mounting substrate  1 C. 
     In  FIG. 16 , the mounting substrate  1 C on which the multiple LEDs  1 A are provided is fixed to the supporting member  1 D via a spacer  1 E. The supporting member  1 D is fixed to an LED attachment part  2 A provided near the front end (near the left end in  FIG. 16 ) of the casing unit  2  formed in a substantially cylindrical shape. Specifically, the supporting member  1 D is fixed to the LED attachment part  2 A at multiple positions (four positions, for example) in a circumferential direction with well-known means, such as screws (not illustrated). The cover  3  of a ring shape formed of a transparent synthetic resin material is provided to cover the multiple LEDs  1 A arranged in a ring and is attached to the supporting member  1 D at multiple positions in an inner peripheral edge part and an outer peripheral edge part. Alternatively, the outer peripheral edge part of the cover  3  may be fixed to the front end part (left end part in  FIG. 16 ) of the casing unit  2 , and the inner peripheral edge part may be fixed to the supporting member  1 D. 
     In  FIGS. 14 and 16 , the rear end (right side in  FIGS. 14 and 16 ) of the casing unit  2  is a side attached to the cosmetic appliance  180 , and an attachment part  2 B for a hair dryer is formed near the rear end of the casing unit  2 . The attachment part  2 B for a hair dryer will be detailed later with reference to  FIGS. 18-20 . When the light irradiation device  210  comprising the LED unit  1  and the casing unit  2  is attached near the air outlet of the cosmetic appliance  180  (not illustrated in  FIGS. 14-16 ), warm air or cool air from the cosmetic appliance  180  flows into the light irradiation device  210 , as indicated by an arrow F 1  in  FIG. 16 , and is provided from the LED unit  1  side of the light irradiation device  210  to the user&#39;s hair, as indicated by an arrow F 2 . 
     The multiple LEDs  1 A may be selected from among LEDs that emit light with a wavelength from 620 nm to 670 nm (red), LEDs that emit light with a wavelength from 450 nm to 480 nm (blue), LEDs that emit light with a wavelength from 560 nm to 600 nm (yellow), and LEDs that emit light with a wavelength from 500 nm to 530 nm (green), in consideration of the effect of restoring skin provided by each of the LEDs. When selecting the LEDs  1 A, LEDs in one of the abovementioned wavelength ranges may be selected, or LEDs in two or more of the abovementioned wavelength ranges may be selected, so as to be attached to the light irradiation device  210 . Alternatively, LEDs in all of the abovementioned wavelength ranges may be selected to be attached to the light irradiation device  210 . 
       FIG. 17  shows the state where the light irradiation device  210  is attached to the cosmetic appliance  180 . 
     In  FIG. 17 , the light irradiation device  210  as described with reference to  FIGS. 14-16  is attached near an air outlet  101 B for warm air or cool air of the cosmetic appliance  180 . The cosmetic appliance  180  shown in  FIG. 17  comprises an attachment structure for the light irradiation device  210 , and a mechanism for supplying electric power to the light irradiation device  210 . 
     In  FIG. 17 , air is drawn in through an air inlet  101 A by means of rotation of a blower fan  103  and then sent to a heater  105 . In  FIG. 17 , air F 3  sent to the heater  105  is indicated by an arrow. When a user of the cosmetic appliance  180  is to use warm air, the air F 3  thus sent is heated by the heater  105 , and, when the user is to use cool air, the air F 3  is not heated. Thereafter, the heated or non-heated air (warm air or cool air: arrow F 4 ) is provided through the air outlet  101 B to the light irradiation device  210 , passes through the inside (air passage) of the light irradiation device  210 , and is then provided from the LED unit  1  side (left side in  FIG. 17 ) toward the user&#39;s hair (arrow F 5 ). 
     As shown in  FIG. 17 , with the cosmetic appliance  180  to which the light irradiation device  210  is attached, warm air or cool air is provided toward the user&#39;s hair (target of cosmetic treatment), and, at the same time, the scalp of the user is irradiated with light with a specific wavelength emitted by the LEDs  1 A. Namely, the user can concurrently receive the effect of hair styling provided by the cosmetic appliance  180  and the effect of improving the scalp by LED irradiation provided by the light irradiation device  210 , thereby efficiently acquiring the beauty effects. Also, supplying air by the cosmetic appliance  180  and light irradiation by the LEDs of the light irradiation device  210  can also be performed separately. 
     Although not illustrated, operating an operation switch part  107  of the cosmetic appliance  180  enables turning on and off of the light irradiation device  210 , specification of an LED to be turned on (selection of a wavelength to be used), and selection and adjustment of strength of light emitted by the LED. In  FIG. 17 , an attachment section B is a section where the light irradiation device  210  is attached to the cosmetic appliance  180  and will be described below with reference to  FIGS. 18-20 . 
     In  FIG. 18A , the attachment part  2 B is provided near the rear end part (near the right end part in  FIGS. 14, 16, and 17 ) of the cosmetic appliance  180 . The attachment part  2 B is integrally formed with the casing unit  2  and includes a body side part  2 B 1  of the casing unit  2 , a vertical part  2 B 2  that extends from the body side part  2 B 1  radially inward and substantially vertically, and a horizontal part  2 B 3  that extends from the radially inner end part {the lower end in  FIG. 18A } of the vertical part  2 B 2  in the axial direction (horizontally) toward the light irradiation device  210  side {the right side in  FIG. 18A }. Near the rear end {right end in  FIG. 18A } of the horizontal part  2 B 3 , a protruding part  2 B 4  that protrudes radially inward is formed. 
     In the radially inner part {lower part in  FIG. 18A } of the protruding part  2 B 4  is embedded an electrode  2 B 5 , via which operating power is provided to the LED unit  1  of the light irradiation device  210 . The attachment part  2 B is provided at multiple positions (four positions, for example) that are substantially evenly spaced in a circumferential direction. Meanwhile, the electrode  2 B 5  may be provided in at least one position. Since the attachment part  2 B is provided at multiple positions (four positions, for example) substantially evenly spaced in a circumferential direction, the horizontal parts  2 B 3  of the attachment parts  2 B extend in an axial direction (the left or right direction in  FIGS. 18 and 19 ) in parts of the circumferential direction. Namely, the horizontal part  2 B 3  does not extend in an axial direction over the entire range of the circumferential direction. 
     In  FIG. 18A , near the front end part {left end part in  FIG. 18A } of the cosmetic appliance  180 , an attachment part  102 B of the cosmetic appliance  180  side is provided. Near the front end of a body case  101  and on the outer peripheral side thereof is provided a locking member  310 , which extends substantially in parallel with an axial direction of the cosmetic appliance  180  by means of a fastening member  112 . In the front end part {the light irradiation device  210  side} of the locking member  310 , a protruding part  111  that protrudes radially outward is formed. Between the locking member  310  and the body case  101  is provided a spacer  113 , so that, if the locking member  310  is elastically deformed in a radial direction when the light irradiation device  210  is attached, the displacement can be absorbed. 
     Near the front end {left end in  FIG. 18A } of the locking member  310 , an electrode  308  is embedded in the rear side {the right side in  FIG. 18A } of the protruding part  111 . Via a non-illustrated circuit, electric power from a power supply in the cosmetic appliance  180  is supplied to the electrode  308 . The entire of the attachment part in the cosmetic appliance  180 , including the locking member  310  and the like, is provided as the attachment part  102 B. The attachment part  102 B of the cosmetic appliance  180  is formed at multiple positions (four positions, for example) substantially evenly spaced in a circumferential direction so as to correspond to the attachment parts  2 B of the light irradiation device  210 . 
     In order to attach the light irradiation device  210  to the cosmetic appliance  180 , the position of an attachment part  2 B of the light irradiation device  210  is set to the position of an attachment part  102 B of the cosmetic appliance  180 , and the attachment part  2 B of the light irradiation device  210  is inserted in the direction toward the attachment part  102 B of the cosmetic appliance  180  {direction of an arrow AR 1 : the right side in  FIG. 18A }. When the attachment part  2 B of the light irradiation device  210  is inserted to the attachment part  102 B of the cosmetic appliance  180 , the protruding part  2 B 4  on the horizontal part  2 B 3  in the light irradiation device  210  resists elastic repulsion between the horizontal part  2 B 3  and the locking member  310  and passes over the protruding part  111  on the locking member  310  in the cosmetic appliance  180 . Accordingly, the protruding part  2 B 4  is engaged with the protruding part  111 , as shown in  FIG. 18B . At the time, the upper edge part of the fastening member  112  in the cosmetic appliance  180  abuts onto the horizontal part  2 B 3  (protruding part  2 B 4 ), thereby preventing the horizontal part  2 B 3  (protruding part  2 B 4 ) excessively intruding into the cosmetic appliance  180  side (the right side in  FIG. 18 ) (the upper edge part functions as a stopper). 
     As stated above, the part where the attachment part  2 B and the attachment part  102 B, which each extend in an axial direction (the left or right direction in  FIG. 18 ), are engaged with each other is provided at multiple positions (four positions, for example) in a circumferential direction, so that the light irradiation device  210  can be attached to the cosmetic appliance  180 . When the light irradiation device  210  is attached to the cosmetic appliance  180  in the state shown in  FIG. 18B , the electrode  2 B 5  of the light irradiation device  210  abuts against the electrode  308  of the cosmetic appliance  180 . In other words, since the electrode  2 B 5  of the light irradiation device  210  and the electrode  308  of the cosmetic appliance  180  are set so that the attachment part  2 B and the attachment part  102 B are engaged with and abut against each other, current flows between the electrode  2 B 5  and the electrode  308 . Accordingly, electric power required for the LED unit  1  of the light irradiation device  210  to emit light is supplied from a power supply (an existing power supply) in the cosmetic appliance  180 , through the electrode  308  of the cosmetic appliance  180  and the electrode  2 B 5  of the light irradiation device  210 . 
     In order to detach the light irradiation device  210  from the cosmetic appliance  180 , the user may hold, with fingers, the horizontal parts  2 B 3  of the attachment parts  2 B of the light irradiation device  210  from the both sides in a circumferential direction and then move the protruding parts  2 B 4  on the horizontal parts  2 B 3  radially outward. The protruding parts  2 B 4  can be easily moved radially outward, and the attachment parts  2 B and the attachment parts  102 B are disengaged from each other, so that no current flows between the electrodes  2 B 5  and the electrodes  308 , and the light irradiation device  210  is detached from the cosmetic appliance  180 . 
     With reference to  FIG. 19 , a first modification of the structure for attaching the light irradiation device  210  to the cosmetic appliance  180  will be described. In  FIG. 19A , an attachment part  2 BA is integrally formed with the casing unit  2  near the rear end part {the right end part in  FIG. 19A } of the light irradiation device  210  and includes a body side part  2 BA 1  of the casing unit  2 , a vertical part  2 BA 2  that extends from the body side part  2 BA 1  radially inward and substantially vertically, and a horizontal part  2 BA 3  that substantially horizontally extends from the radially inner end {the lower end in  FIG. 19A } of the vertical part  2 BA 2  in an axial direction of the light irradiation device  210  (the left or right direction in  FIG. 19 ). 
     On the surface (inner peripheral surface) of the radially inner side {lower side in  FIG. 19A } of the horizontal part  2 BA 3  and on the rear end side thereof {right side in  FIG. 19A }, a female thread  2 BA 4  is formed. 
     On the female thread  2 BA 4 , a notch (no symbol in the figures) is formed near the center in an axial direction, and an electrode  2 BA 5  is embedded in the notch. Via the electrode  2 BA 5 , electric power required for the LED unit  1  of the light irradiation device  210  to emit light is supplied. The female thread  2 BA 4  is formed over the entire range of the circumferential direction on the attachment part  2 BA, but the electrode  2 BA 5  need not be formed over the entire range of the circumferential direction. As will be described later, it may be sufficient as long as the electrode  2 BA 5  is formed to be certainly contactable with an electrode  314  of the cosmetic appliance  180 . 
     In  FIG. 19A , near the front end part {left end in  FIG. 19A } of the cosmetic appliance  180 , an attachment part  102 BA of the cosmetic appliance  180  side is provided. Near the front end {left end in  FIG. 19A } of the body case  101  of the cosmetic appliance  180  and on the outer peripheral side {upper side in  FIG. 19A } thereof is provided a projection  109 , and a male thread  109 A is formed on the outer peripheral side of the projection  109 . The outer peripheral surface {upper surface in  FIG. 19A } of the projection  109  is substantially in parallel with an axial direction (the left or right direction in  FIG. 19 ). In  FIG. 19A , a protrusion  109 B is a protrusion integrally formed with the projection  109  and functions as a stopper for the female thread  2 BA 4  when the light irradiation device  210  is attached. 
     On the male thread  109 A, a notch (no symbol in the figures) is formed near the center in an axial direction, and an electrode  314  is embedded in the notch and connected to a power supply in the cosmetic appliance  180  via a non-illustrated circuit. The attachment part  102 BA of the cosmetic appliance  180  is provided over the entire range of the circumference to correspond to the attachment part  2 BA of the light irradiation device  210 , whereas the electrode  314  is provided according to the position of the electrode  2 BA 5  of the light irradiation device  210 . In other words, the electrode  314  is provided at a position that is certainly contactable with the electrode  2 BA 5  when the light irradiation device  210  is attached to the cosmetic appliance  180 . 
     In  FIG. 19A , in order to attach the light irradiation device  210  to the cosmetic appliance  180 , the attachment part  2 BA of the light irradiation device  210  is set to the attachment part  102 BA of the cosmetic appliance  180 , and the attachment part  2 BA of the light irradiation device  210  is rotated so that the female thread  2 BA 4  is threadedly engaged with the male thread  109 A. In this way, by threadedly engaging the female thread  2 BA 4  of the light irradiation device  210  and the male thread  109 A of the cosmetic appliance  180 , the light irradiation device  210  is attached to the cosmetic appliance  180  in the state shown in  FIG. 19B . 
     When the light irradiation device  210  is attached to the cosmetic appliance  180  as shown in  FIG. 19B , the electrode  2 BA 5  of the light irradiation device  210  is in contact with the electrode  314  of the cosmetic appliance  180 , so that current flows between the electrode  2 BA 5  and the electrode  314 . Accordingly, electric power required for the LED unit  1  of the light irradiation device  210  to emit light is supplied from a power supply in the cosmetic appliance  180 , through the electrode  314  of the cosmetic appliance  180  and the electrode  2 BA 5  of the light irradiation device  210 . In order to detach the light irradiation device  210  from the cosmetic appliance  180  in the state shown in  FIG. 19B , the user may rotate the attachment part  2 BA of the light irradiation device  210  so that the female thread  2 BA 4  and the male thread  109 A are disengaged from each other. 
     With reference to  FIG. 20 , a second modification of the structure for attaching the light irradiation device  210  to the cosmetic appliance  180  will be described. In  FIG. 20A , an attachment part  2 BB is integrally formed with the casing unit  2  near the rear end part {the right end side in  FIG. 20A } of the light irradiation device  210  and includes a body side part  2 BB 1  of the casing unit  2 , a vertical part  2 BB 2  that extends from the body side part  2 BB 1  radially inward and substantially vertically, and a horizontal part  2 BB 3  that horizontally extends from the radially inner end part {the lower end in  FIG. 20A } of the vertical part  2 BB 2  in an axial direction of the light irradiation device  210  (the left or right direction in  FIG. 20 ). Near an end part {the right end in  FIG. 20A } of the horizontal part  2 BB 3 , a locking member  2 BB 4 , including a support shaft  2 BB 4 A and a locking part  2 BB 4 B of a rectangle ring shape are provided, and a locking member  2 BB 4  is rotatably supported by the support shaft  2 BB 4 A at one end. 
     Near the rear end of the horizontal part  2 BB 3  and on the radially inner surface {lower surface in  FIG. 20A } thereof is embedded an electrode  2 BB 5 , via which electric power required for the LED unit  1  of the light irradiation device  210  to emit light is supplied. The attachment part  2 BB is provided at multiple positions (four positions, for example) that are substantially evenly spaced in a circumferential direction. Meanwhile, the electrode  2 BB 5  may be provided in at least one position. 
     In  FIG. 20A , the cosmetic appliance  180  is provided with an attachment part  102 BB. Near the front end {left end in  FIG. 20A } of the body case  101  and on the outer peripheral side {upper side in  FIG. 20A } thereof is provided a projection  315 , and, on the outer peripheral side {upper side in  FIG. 20A } of the projection  315 , a lock reception part  316  is provided for the locking member  2 BB 4  of the light irradiation device  210 . To the side closer to the light irradiation device  210  (to the left side in  FIG. 20 ) of the projection  315  and on the outer peripheral side {upper side in  FIG. 20A } is embedded an electrode  317 , to which electric power is supplied from a power supply in the cosmetic appliance  180  via a non-illustrated circuit. 
     The inner peripheral surface {lower surface in  FIG. 20A } of the horizontal part  2 BB 3  in the light irradiation device  210  and the outer peripheral surface {upper surface in  FIG. 20A } of the body case  101  in the cosmetic appliance  180  are set so as to be flush with each other when the light irradiation device  210  is attached to the cosmetic appliance  180 . The size in a radial direction (thickness) of the projection  315  provided on the body case  101  is substantially identical with the size in a radial direction (thickness) of the horizontal part  2 BB 3  of the attachment part  2 BB in the light irradiation device  210 . When the light irradiation device  210  is attached to the cosmetic appliance  180 , the projection  315  functions as a stopper for the horizontal part  2 BB 3  of the light irradiation device  210 . The attachment part  102 BB of the cosmetic appliance  180  is provided at multiple positions (four positions, for example), which correspond to the positions of the attachment parts  2 BB of the light irradiation device  210 , substantially evenly spaced in a circumferential direction. 
     When the light irradiation device  210  is to be attached to the cosmetic appliance  180 , the position of an attachment part  2 BB of the light irradiation device  210  is set to an attachment part  102 BB of the cosmetic appliance  180 . Subsequently, the attachment part  2 BB is inserted toward the attachment part  102 BB (in the direction of an arrow AR 3 ) until the tip {right end in  FIG. 20A } of the horizontal part  2 BB 3  abuts onto the projection  315 . Thereafter, by rotationally moving, clockwise in  FIG. 20A , the locking part  2 BB 4 B of a rectangle ring shape of the locking member  2 BB 4  on the horizontal part  2 BB 3  so that the locking part  2 BB 4 B is engaged with the lock reception part  316 , the light irradiation device  210  can be attached to the cosmetic appliance  180  {the state shown in  FIG. 20B }. In order to detach the light irradiation device  210  from the cosmetic appliance  180  in the state shown in  FIG. 20B , the user may rotationally move the locking part  2 BB 4 B counterclockwise in  FIG. 20B  so that the locking part  2 BB 4 B is disengaged from the lock reception part  316 . 
     In this way, by engaging the attachment parts  2 BB of the light irradiation device  210  and the attachment parts of the cosmetic appliance  180  at multiple positions (four positions, for example), the light irradiation device  210  is certainly attached to the cosmetic appliance  180  in the state shown in  FIG. 20B . When the light irradiation device  210  is attached to the cosmetic appliance  180  as shown in  FIG. 20B , the electrode  2 BB 5  of the light irradiation device  210  is in contact with the electrode  317  of the cosmetic appliance  180 , so that current flows between the electrode  2 BB 5  and the electrode  317 . Accordingly, electric power required for the LED unit  1  of the light irradiation device  210  to emit light can be supplied from a power supply in the cosmetic appliance  180 , through the electrode  317  of the cosmetic appliance  180  and the electrode  2 BB 5  of the light irradiation device  210 . 
     There will now be described the direction of light emitted by each of the LEDs of the light irradiation device  210  according to the second embodiment, with reference to  FIGS. 21, 22, and 23 . As stated previously with reference to  FIGS. 14 and 15 , the multiple LEDs  1 A in the LED unit  1  are arranged in a circle to be substantially evenly spaced on the mounting substrate  1 C, which is not illustrated. Each of the LEDs  1 A is arranged so as to emit light in a direction inclined radially inward with respect to an axial direction of the light irradiation device  210  (the left or right direction in  FIGS. 16 and 22 ), and the light emitted by each of the LEDs  1 A travels in a direction inclined radially inward with respect to an axial direction. In  FIGS. 21 and 22 , the traveling direction of light emitted by each of the LEDs is indicated by an arrow L. 
     Although not clearly illustrated in  FIGS. 21 and 22 , by adjusting the orientation of each of the LEDs  1 A when arranging the LEDs  1 A on the mounting substrate  1 C (see  FIG. 16 ), light emitted by each of the LEDs  1 A can be set to travel in a direction inclined radially inward with respect to an axial direction. Alternatively, the mounting substrate on which the LEDs  1 A are arranged may be formed in the shape of a mounting substrate  1 CA shown in  FIG. 23 . The mounting substrate  1 CA shown in  FIG. 23  is not a ring-shaped flat plate, and an LED attachment surface  1 CAS of a ring shape is formed to be thicker toward the outside in the radial direction, and hence, the LED attachment surface  1 CAS for the LEDs  1 A is inclined. In  FIG. 23 , a through hole  1 CAH is a through hole. The configuration for setting the LEDs  1 A to be inclined is not limited to that described above, and various configurations may be employed therefor. 
     According to the second embodiment shown in  FIGS. 14-23 , in addition to warm air or cool air provided by the cosmetic appliance  180 , light emitted by the multiple LEDs  1 A provided in the light irradiation device  210  is delivered to the scalp of a user, so that the light emitted by the LEDs  1 A, having a certain wavelength, improves cell activity, increases fibroblasts, produces a growth factor, produces collagen, and increases vascularization in the user&#39;s scalp, thereby exerting a favorable influence on the skin tissue and hair and placing the scalp in favorable condition. 
     Also, since the light irradiation device  210  is configured to be attachable to and detachable from the cosmetic appliance  180 , the light irradiation device  210  can be easily applied to a conventional cosmetic appliance  180 . In other words, the second embodiment is applicable without significantly modifying the conventional cosmetic appliance  180 . 
     Also, according to the second embodiment as shown in the figures, since the multiple LEDs  1 A provided in the light irradiation device  210  are arranged in a circle and the LEDs  1 A are arranged so that light emitted by each of the LEDs  1 A travels in a direction inclined toward a region radially inside the circle, light emitted by the LEDs  1 A will not reach an eye of a user of the cosmetic appliance  180  according to the present invention. This prevents the light emitted by the LEDs  1 A damaging the user&#39;s eyes. 
     In addition, according to the second embodiment as shown in the figures, when the light irradiation device  210  is attached to the cosmetic appliance  180 , an electrode of the light irradiation device  210  abuts against an electrode of the cosmetic appliance  180 , so that electric power can be supplied from the cosmetic appliance  180  to the light irradiation device  210 ; accordingly, electric power required for the LEDs  1 A to emit light can be supplied from a power supply in the cosmetic appliance  180 , without newly providing a power supply on the light irradiation device  210  side. 
     Next, a third embodiment of the present invention will be described with reference to  FIG. 24 . 
     In  FIG. 24 , to the air outlet  101 B side (left side in  FIG. 24 ) of the cosmetic appliance  180 , the light irradiation device  220  according to the third embodiment is attached. The light irradiation device  220  is different from the light irradiation device  210  of the second embodiment in comprising the spray device  215 , which is attachable and detachable, on the upper surface of a casing unit  222 . Within the casing unit  222  of the light irradiation device  220 , an upper space is made larger than a lower space or a side space so as to ensure space for the spray unit  15 B of the spray device  215  and space for spraying. Accordingly, the shape of the light irradiation device  220  viewed from the left side in  FIG. 24  is not an exact circle but a vertically-long ellipse. The other configurations of the light irradiation device  220  shown in  FIG. 24  are the same as those of the light irradiation device  210  according to the second embodiment. 
     In  FIG. 24 , the spray device  215  has a function to spray a mist of liquid for so-called “beautiful hair”, such as a hairdressing, within the casing unit  222 . The spray device  215  comprises the liquid storage unit  15 A provided on the upper side of the casing unit  222  in the light irradiation device  220 , the spray unit  15 B provided within the casing unit  222 , and a communicating pipe  15 C that communicates the liquid storage unit  15 A and the spray unit  15 B and that penetrates the upper surface of the casing unit  222 . The spray device  215  is fixed to the upper surface of the casing unit  222  by a fastening member  15 D. For the configuration of fixing the spray device  215  to the upper surface of the casing unit  222 , a member other than the fastening member  15 D may also be used. To the spray device  215 , part of electric power supplied from a power supply in the cosmetic appliance  180  to the light irradiation device  220  is supplied via a non-illustrated circuit. 
     When the light irradiation device  220  is attached to the cosmetic appliance  180  and an operation switch part  318  of the cosmetic appliance  180  is operated to start the hair dryer, warm air or cool air passes through an airflow passage within the cosmetic appliance  180  and an air passage within the light irradiation device  220 , and is then provided through the outlet of the light irradiation device  220  toward the user&#39;s hair (target of cosmetic treatment), as indicated by an arrow F 6 . In  FIG. 24 , when the operation switch part  318  is operated to start the spray device  215 , a mist of liquid for beautiful hair is sprayed by the spray unit  15 B of the spray device  215  into the air passage in the light irradiation device  220  (arrow F 7 ). 
     The mist of liquid for beautiful hair sprayed by the spray device  215  is carried by the warm air or cool air provided by the cosmetic appliance  180  and efficiently delivered to the user&#39;s hair as the target of cosmetic treatment. Even when air is not provided by the cosmetic appliance  180 , with the spraying power of the spray device  215 , the liquid for beautiful hair stored in the spray device  215  can be delivered to the user&#39;s hair. Also, by turning on the LEDs  1 A of the light irradiation device  220  in addition to spraying the liquid for beautiful hair from the spray device  215 , the scalp of the user is irradiated with light with a specific wavelength emitted by the LEDs  1 A, thereby also improving the condition of the user&#39;s scalp. 
     According to the third embodiment shown in  FIG. 24 , since the spray device  215  is provided to be attachable to and detachable from the light irradiation device  220  and the spray device  215  includes the spray unit for spraying a mist of liquid for beautiful hair, there can be obtained the effect of favorable hair condition due to the spraying of the liquid for beautiful hair, in addition to the effects of setting a hairstyle using warm air or cool air and the activation of the scalp by LED irradiation. Especially, by spraying the liquid for beautiful hair in the warm air or cool air provided by the cosmetic appliance  180 , the mist of the liquid for beautiful hair is carried by the warm air or cool air from the cosmetic appliance  180  and efficiently delivered to the user&#39;s hair as the target of cosmetic treatment. The other configurations and effects of the third embodiment shown in  FIG. 24  are the same as those of the second embodiment described with reference to  FIGS. 14-23 . 
     Next, a fourth embodiment of the present invention will be described with reference to  FIGS. 25 and 26 . 
     Although the cosmetic appliance  180  in the second and third embodiments shown in  FIGS. 14-24  is a hair dryer, the cosmetic appliance  280  in the fourth embodiment shown in  FIGS. 25 and 26  is a facial roller (facial instrument). The cosmetic appliance  280  as a facial roller includes a pair of rollers  202  provided vertically on a head part  201 , and the rollers  202  are rotated by means of a non-illustrated power supply so as to massage facial skin, providing the effects of stimulating blood flow and activating metabolism in the facial skin. In  FIGS. 25 and 26 , an operation switch part  204  is an operation switch part. 
     In  FIG. 25 , a light irradiation device  230  is similar to the light irradiation device  210  of the second embodiment but different from the light irradiation device  210  in sizes, such as the inner and outer diameters and the length in a side surface direction, and the number of the LEDs  1 A, for example, because the light irradiation device  230  is attached to the cosmetic appliance  280  instead of the cosmetic appliance  180 . Since the rollers  202  of the cosmetic appliance  280  need to protrude from an LED unit  31  at the front end of the light irradiation device  230  when the light irradiation device  230  is attached to the cosmetic appliance  280  (see  FIG. 26 ), a length L 12  in an axial direction of the light irradiation device  230  (the left or right direction in  FIGS. 25 and 26 ) is set to be smaller than that in the embodiments shown in  FIGS. 14-24 . An attachment mechanism  32 B used to attach the light irradiation device  230  to the cosmetic appliance  280 , and a mechanism for supplying electric power from the cosmetic appliance  280  are similar to those in the embodiments shown in  FIGS. 14-24 . 
     In  FIG. 26 , which shows the state where the light irradiation device  230  is attached to the cosmetic appliance  280 , the rollers  202  protrude from the light irradiation device  230  in the light irradiation direction (left direction in  FIG. 26 ). In order to achieve the facial effect of the cosmetic appliance  280 , the rollers  202  need to come into contact with the user&#39;s face; however, if the rollers  202  do not protrude from the light irradiation device  230  in the light irradiation direction (left direction in  FIG. 26 ), the light irradiation device  230  will be in contact with the user&#39;s face, so that the rollers  202  are unable to come into contact with the user&#39;s face. 
     When the cosmetic appliance  280  is used, the operation switch part  204  is operated to start the light irradiation device  230 , and light with a desired wavelength and strength is emitted from the LEDs, thereby activating the user&#39;s skin. Further, when the light irradiation device  230  is attached to the cosmetic appliance  280  to be used, as shown in  FIG. 26 , the cosmetic appliance  280  is stated to perform treatment of the face as the target of cosmetic treatment, and, subsequently, the scalp can be activated by allowing the light irradiation device  230  to emit light. 
     According to the fourth embodiment shown in  FIGS. 25 and 26 , facial skin treatment can be performed for a user by means of the cosmetic appliance  280  and, in addition, the user&#39;s scalp can be irradiated with LED light emitted by the light irradiation device  230 , thereby improving cell activity, increasing fibroblasts, producing a growth factor, producing collagen, and increasing vascularization in the user&#39;s scalp, so as to exert a favorable influence on the skin tissue and hair and to place the scalp in favorable condition. Therefore, the beauty effects can be synergistically improved. The other configurations and effects of the fourth embodiment shown in  FIGS. 25 and 26  are the same as those of the second embodiment described with reference to  FIGS. 14-23 . 
     The present embodiment also includes the following configurations. 
     1 A light irradiation device comprising a plurality of light emitting diodes (LEDs) and configured to be attachable to and detachable from a cosmetic appliance. 
     2 The light irradiation device of claim  1 , wherein the plurality of LEDs are arranged in a closed shape formed by a curve, and light emitted by each of the LEDs travels in a direction inclined toward an inner region of the closed shape. 
     3 The light irradiation device of claim  1  or  2 , further comprising a spray device configured to be attachable and detachable and comprising liquid storage unit and a spray unit that sprays a mist of liquid stored in the liquid storage unit. 
     In the drawings used for the description, hatching is provided on the cross sections of part of the members in order to clarify the relationships between the members; however, such hatching is not provided to limit the materials of the members. 
     INDUSTRIAL APPLICABILITY 
     The present invention is to provide a technique of a light irradiation device for irradiating the scalp or the like of a user with light, in which the amount of light delivered to the scalp or the like can be increased while the influence of light that enters an eye is reduced.