Patent Publication Number: US-2023134497-A1

Title: Vehicular lamp fitting and radar structure

Description:
BACKGROUND 
     The present disclosure relates to a vehicular lamp fitting and a radar structure, and in particular to a vehicular lamp fitting and a radar structure in which a radar unit can be replaced without replacing the whole vehicular lamp fitting. 
     International Patent Publication No. WO2018/173855 (hereinafter also referred to as Patent Literature 1) discloses a vehicular lamp fitting including a lamp housing, an outer lens (optically-transparent member) attached to the lamp housing and forming a lamp chamber between the outer lens and the lamp housing, a lamp unit, and a radar unit (a radar apparatus), in which the lamp unit and the radar unit are disposed in the lamp chamber (see, in particular, FIG. 2 of Patent Literature 1). The radar unit is used for detecting an object by transmitting a high-frequency electromagnetic wave (e.g., millimeter wave) around a vehicle and receiving a reflected wave from the object existing within a transmission range of the electromagnetic wave. 
     SUMMARY 
     However, in the vehicular lamp fitting disclosed in Patent Literature  1 , maintenance (a repair or replacement) of the radar unit is not taken into consideration, and therefore there is a problem that when a failure occurs in the laser unit and it needs to be replaced, the whole vehicular lamp fitting has to be replaced. 
     The present disclosure has been made in order to solve the above-described problem, and an object thereof is to provide a vehicular lamp fitting and a radar structure in which a radar unit can be replaced without replacing the whole vehicular lamp fitting. 
     A vehicular lamp fitting according to an aspect includes: a lamp housing; an outer lens attached to the lamp housing and forming a lamp chamber between the outer lens and the lamp housing; a lamp unit disposed in the lamp chamber; a bracket; and a radar unit detachably fixed to the bracket, in which a through hole connected to the lamp chamber is formed in the lamp housing, the bracket includes a first part and a second part, the first part being configured to be disposed in the lamp chamber through the through hole, and the second part being configured to close the through hole in a state where the first part is disposed in the lamp chamber, the vehicular lamp fitting further includes a fixing part configured to detachably fix the bracket to the lamp housing in a state in which the first part is disposed in the lamp chamber and the second part closes the through hole, and the radar unit is disposed in the lamp chamber while being detachably fixed to the first part. 
     By the above-described configuration, the radar unit can be replaced without replacing the whole vehicular lamp fitting. 
     This is because the radar unit is detachably fixed to the bracket, which is detachably fixed to the lamp housing in the state in which the first part is disposed in the lamp chamber and the second part closes the through hole formed in the lamp housing. 
     Further, in the above-described vehicular lamp fitting, the first part may extend to a vicinity of the outer lens, and the radar unit may be detachably fixed to a tip of the first part. 
     Further, in the above-described vehicular lamp fitting, the through hole may be a through hole connecting a rear surface of the lamp housing to the lamp chamber, or a through hole connecting a lower surface of the lamp housing to the lamp chamber. 
     Further, in the above-described vehicular lamp fitting, the through hole may be a through hole having a polygonal outer shape, and a cross-sectional shape of the bracket may be a polygonal shape conforming to that of the through hole. 
     Further, in the above-described vehicular lamp fitting, in one of the first part and the lamp housing, a positioning rib configured to abut against the other of the first part and the lamp housing may be provided. 
     Further, in the above-described vehicular lamp fitting, a vertical wall (standing wall) part surrounding the through hole may be formed in the lamp housing. 
     Further, in the above-described vehicular lamp fitting, a cut-out part surrounded by side surfaces of a closure part and an extension part may be formed in the bracket, and a connector detachably fixed to a radar-unit holding part may be disposed in the cut-out part. 
     Further, in the above-described vehicular lamp fitting, a through hole through which a cable extending from the connector is drawn to the outside of the lamp chamber may be formed in the closure part. 
     A radar structure according to another aspect includes: a bracket including a first part and a second part, the first part being configured to be disposed in a lamp chamber through a through hole formed in a lamp housing, the lamp chamber being formed by the lamp housing and an outer lens attached to the lamp housing, the second part being configured to close the through hole in a state where the first part is disposed in the lamp chamber, and the bracket being configured to be detachably fixed to the lamp housing in a state in which the first part is disposed in the lamp chamber and the second part closes the through hole; and a radar unit disposed in the lamp chamber while being detachably fixed to the bracket. 
     According to the present disclosure, it is possible to provide a vehicular lamp fitting and a radar structure in which a radar unit can be replaced without replacing the whole vehicular lamp fitting. 
     The above and other objects, features and advantages of the present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a front view of a vehicular lamp fitting  10 ; 
         FIG.  2    is an exploded perspective view of the vehicular lamp fitting  10 ; 
         FIG.  3    is a cross-sectional view taken along a line A-A in  FIG.  1   ; 
         FIG.  4    is a cross-sectional view taken along a line B-B in  FIG.  1   ; 
         FIG.  5    is a view as seen in a direction indicated by an arrow  80  in  FIG.  4   ; 
         FIG.  6    is a perspective view of a bracket  50 ; 
         FIG.  7    is a rear view of a lamp housing  20  to which the bracket  50  is fixed; 
         FIG.  8    shows a modified example of the vehicular lamp fitting  10 ; 
         FIG.  9 A  shows a modified example of the vehicular lamp fitting  10 ; and 
         FIG.  9 B  shows a modified example of the vehicular lamp fitting  10 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A vehicular lamp fitting  10 , which is an embodiment according to the present disclosure, will be described hereinafter with reference to the attached drawings. The same reference numerals (or symbols) are attached to corresponding components throughout the drawings, and redundant explanations thereof are omitted as appropriate. 
       FIG.  1    is a front view of the vehicular lamp fitting  10 . 
     The vehicular lamp fitting  10  according to this embodiment is a signal lamp for a vehicle that functions as a rear combination lamp, and is mounted on each of the left and right sides of the rear end of a vehicle such as an automobile (not shown). Since the vehicular lamp fittings  10  mounted on both the left and right sides of the rear end of the vehicle are symmetrical to each other, only the vehicular lamp fitting  10  mounted on the left side (the left side when facing the front side of the vehicle) of the rear end of the vehicle will be described hereinafter as a representative example. 
       FIG.  2    is an exploded perspective view of the vehicular lamp fitting  10 .  FIG.  3    is a cross-sectional view taken along a line A-A in  FIG.  1   .  FIG.  4    is a cross-sectional view taken along a line B-B in  FIG.  1   . 
     As shown in  FIG.  2   , the vehicular lamp fitting  10  includes a lamp housing  20 , an outer lens  30 , lamp units  40  ( 40 A to  40 C, not shown in  FIG.  2   , see  FIG.  5   ), a bracket  50 , a radar unit  60 , and a gasket  70 . 
     The outer lens  30  is made of a material that is transparent to light (visible light) emitted by the lamp unit  40 , and, for example, made of a transparent resin (a synthetic resin) such as acrylic and polycarbonate. The outer lens  30  is attached to the lamp housing  20  in a state in which it covers the opening of the lamp housing  20 , and forms a lamp chamber S 1  between the outer lens  30  and the lamp housing  20  (see  FIGS.  3  and  4   ). The outer lens  30  is welded to the lamp housing  20  (the opening end) along its whole peripheral edge. 
     The lamp housing  20  is made of a synthetic resin such as acrylic and polycarbonate, and a through hole  21  connecting (i.e., extending) to the lamp chamber S 1  is formed in the lamp housing  20  (see  FIGS.  2 ,  3  and  5   ). The through hole  21  is a through hole having a rectangular outer shape. The through hole  21  connects the rear surface of the lamp housing  20  to the lamp chamber S 1  (i.e., extends from the rear surface of the lamp housing  20  to the lamp chamber S 1 ). A rectangular ring-shaped vertical wall part (e.g., a perpendicular wall part)  22  surrounding the through hole  21  (see  FIG.  2   ) is provided on the front side of the lamp housing  20 . 
     As shown in  FIG.  4   , the outer lens  30  includes a rear lens part  31  disposed on the rear end side of the vehicle and a side lens part  32  disposed on the lateral side of the vehicle. The rear lens part  31  and the side lens part  32  are continuous through a curved part  33 . Note that the outer lens  30  may have an arbitrary shape as desired according to the design of the vehicle or the like. 
       FIG.  5    is a perspective view as seen in a direction indicated by an arrow  80  in 
       FIG.  4   .  FIG.  5    shows an example of the arrangement of the lamp units  40  ( 40 A to  40 C) and the radar unit  60 . Note that the number and the arrangement of the lamp units  40  are not limited to the example shown in  FIG.  5   , and they may be determined as appropriate. 
     The lamp units  40  ( 40 A to  40 C) are disposed in the lamp chamber S 1 , which is formed by the outer lens  30  and the lamp housing  20 . 
     The lamp unit  40 A is, for example, a lamp unit for both a stop lamp and a tail lamp, and includes a reflector(s) (a reflective surface(s)) for both the stop lamp and the tail lamp (not shown), and a light source(s) for both the stop lamp and the tail lamp (not shown). When the light source for both the stop lamp and the tail lamp is turned on, light emitted from the light source for both the stop lamp and the tail lamp is reflected by the reflector (the reflective surface) for both the stop lamp and the tail lamp, passes through the outer lens  30 , and is emitted to the outside. In this way, the stop lamp or the tail ramp is implemented. 
     The lamp unit  40 B is, for example, a lamp unit for a stop lamp, and includes a reflector (a reflective surface) for the stop lamp and a light source for the stop lamp (not shown). When the light source for the stop lamp is turned on, light emitted by the light source for the stop lamp is reflected by the reflector (the reflective surface) for the stop lamp, passes through the outer lens  30 , and is emitted to the outside. In this way, the stop lamp is implemented. 
     The lamp unit  40 C is, for example, a lamp unit for a turn lamp (i.e., a blinker), and includes a reflector (a reflective surface) for the turn lamp and a light source for the turn lamp (not shown). When the light source for the turn lamp is turned on, light emitted by the light source for the turn lamp is reflected by the reflector (the reflective surface) for the turn lamp, passes through the outer lens  30 , and is emitted to the outside. In this way, the turn lamp is implemented. 
       FIG.  6    is a perspective view of the bracket  50 . 
     The bracket  50  is made of a synthetic resin such as acrylic and polycarbonate, and as shown in  FIGS.  2  and  6   , includes a rectangular ring-shaped part  51 , a flange part  52  provided in the rectangular ring-shaped part  51 , a closure part  53  that closes (i.e., covers) a part of the rectangular ring-shaped part  51 , an extension part  54  that extends to the vicinity of the outer lens  30 , and a radar-unit holding part  55  disposed at the tip of the extension part  54 . 
     As shown in  FIG.  6   , in the bracket  50 , a space S 2  (a cut-out part, see  FIG.  4   ) surrounded by the closure part  53  and side surfaces  54   a  and  54   b  of the extension part  54  is formed. In this space S 2 , a connector  90  detachably fixed to the radar-unit holding part  55  (or detachably fixed to the radar unit  60 , which is detachably fixed to the radar-unit holding part  55 ) is disposed. 
     The cross-sectional shape of the bracket  50  (the rectangular ring-shaped part  51 ) is a rectangular shape conforming to that of the through hole  21  (the vertical wall part  22 ) formed in the lamp housing  20 . A gasket  70  is provided in the rectangular ring-shaped part  51  (see  FIG.  6   ). 
     The flange part  52  is provided along the whole peripheral edge of the rectangular ring-shaped part  51 . The rectangular ring-shaped part  51  and the flange part  52  are an example of the second part in the present disclosure. 
     The closure part  53  closes (i.e., covers) a part of the rectangular ring-shaped part  51 , i.e., a part of the rectangular ring-shaped part  51  other than the extension part  54 . A through hole for pulling out a cable(s)  91  (a power supply cable and the like) to the outside of the lamp chamber S 1  is formed in the closure part  53 . The cable(s)  91  extends from the connector  90 . The cable(s)  91  supplies power and sends and receives various signals. 
     The extension part  54  is formed in a cylindrical shape by extending the edge portion surrounded by the rectangular ring-shaped part  51  and the closure part  53  to the vicinity of the outer lens  30 . The tip of the extension part  54  is closed (i.e., covered) by the radar-unit holding part  55 . The extension part  54  is an example of the first part in the present disclosure. 
     The length L (see  FIG.  4   ) of the extension part  54  is a length considered so that an electromagnetic wave (millimeter wave) transmitted from the radar unit  60  fixed to the tip part (radar unit holding part  55 ) does not interfere with the surrounding structure (For example, lamp units  40  ( 40  A to  40  C)). The transmission range of the electromagnetic wave (millimeter wave) transmitted from the radar unit  60  is a range of a vertical spreading angle θ v  (see  FIG.  3   ) and a horizontal spreading angle θ H  (see  FIG.  4   ). 
     In the radar-unit holding part  55 , screw bosses  56  (disposed at three places in  FIGS.  2  and  6   ), to which flange parts  62  (disposed at three places in  FIGS.  2  and  6   ) provided in the radar unit  60  (the case  61 ) are fixed by screws, are provided. The screw bosses  56  are disposed at the places (three places in  FIGS.  2  and  6   ) corresponding to the flange parts  62  (three places in  FIGS.  2  and  6   ). 
       FIG.  7    shows a rear view of the lamp housing  20  to which the bracket  50  is fixed. 
     As shown in  FIG.  7   , the bracket  50  is detachably fixed to the lamp housing  20 . Specifically, as shown in  FIGS.  3  and  4   , the bracket  50  is detachably fixed to the lamp housing  20  by fixing the flange part  52  to the lamp housing part around the through hole  21  by screws N 1  (four places in  FIG.  7   ) in a state in which the extension part  54  has been disposed in the lamp chamber S 1  through the through hole  21  and the flange part  52  abuts against (i.e., is in contact with) the lamp housing part around the through hole  21  (see  FIG.  7   ). The screws N 1  are an example of the fixing part in the present disclosure. 
     As described above, as shown in  FIG.  3   , the rectangular ring-shaped part  51  has been inserted into the through hole  21  (the rectangular ring-shaped vertical wall part  22  surrounding the through hole  21 ) in the state in which the bracket  50  is detachably fixed to the lamp housing  20 , and the rectangular ring-shaped part  51  inserted into the through hole  21  and the rectangular ring-shaped vertical wall part  22  surrounding the through hole  21  are opposed to each other. Further, the gasket  70  is disposed between these rectangular ring-shaped part  51  and the vertical wall part  22  opposed to each other. In this way, the lamp chamber S 1  is kept in a hermetically closed state. 
     As shown in  FIG.  2   , the radar unit  60  (the radar apparatus) includes the case  61 , a transmitting antenna and a receiving antenna (both of which are not shown) housed in the case  61 , and so on. The radar unit  60  is a millimeter-wave radar unit that transmits electromagnetic waves (millimeter waves) from the transmitting antenna. The electromagnetic waves (the millimeter waves) pass through the outer lens  30  and are transmitted (emitted) to a range having a vertical divergence angle θ V  (see  FIG.  3   ) and a horizontal divergence angle OH (see  FIG.  4   ). Further, the radar unit  60  receives, by the receiving antenna, reflected waves which have been reflected by an object present in the aforementioned transmission range (the emission range) and have passed through the outer lens  30 . The received signal is processed by a control apparatus such as an ECU (Electronic Control Unit) (not shown), so that the object (e.g., a distance, an angle, and a velocity of the object) is detected. In the radar unit  60 , for example, millimeter waves in a frequency band of 76 to 81 GHz, in particular, in a frequency band of 79 GHz, are used. However, the frequency band is not limited to these frequency bands. 
     Note that the radar method of the radar unit  60  may be either of a pulse method or a CW (Continuous Wave) method, or may be any other method. Further, the antenna method of the radar unit  60  may be any of a mechanical scanning method, a beam switching method, a phased array method, and a digital forming method, or may be any other method. 
     The radar unit  60  is detachably fixed to the bracket  50 . Specifically, as shown in  FIG.  6   , the radar unit  60  is detachably fixed to the bracket  50  (the radar-unit holding part  55 ) by fixing the flange parts  62  (three places in  FIG.  6   ) provided in the case  61  to the screw bosses  56  (three places in  FIG.  6   ) provided in the bracket  50  by screws N 2  (three places in  FIG.  6   ). 
     The vehicular lamp fitting  10  having the above-described configuration is mounted on a vehicle by fixing flange parts  23  and  24  (see  FIG.  2   ) provided in the lamp housing  20  to the vehicle (e.g., the frame of the vehicle body or the bumper) by screws. 
     Next, a procedure for detachably fixing the bracket  50 , to which the radar unit  60  has been detachably fixed as described above, to the lamp housing  20  will be described. 
     Firstly, the extension part  54  of the bracket  50  is disposed in the lamp chamber S 1  through the through hole  21  formed in the lamp housing  20 , and the flange parts  52  of the bracket  50  are brought into contact with the lamp housing part around the through hole  21  formed in the lamp housing  20 . Next, in this state, the flange part  52  is fixed to the lamp housing part around the through hole  21  by screws N 1  (four places in  FIG.  7   ). At this time, the rectangular ring-shaped part  51  is inserted into the through hole  21  (a rectangular ring-shaped vertical wall part  22  surrounding the through hole  21 ), and the rectangular ring-shaped part  51  inserted into the through hole  21  and the rectangular ring-shaped vertical wall part  22  surrounding the through hole  21  are opposed to each other. 
     As a result, the bracket  50  (and the radar unit  60  fixed thereto) is positioned relative to the lamp housing  20  (and the outer lens  30 ) in the up/down and left/right directions. Further, since the flange part  52  of the bracket  50  abuts against (i.e., is in contact with) the lamp housing part around the through hole  21  formed in the lamp housing  20 , the bracket  50  (and the radar unit  60  fixed thereto) is positioned relative to the lamp housing  20  (and the outer lens  30 ) in the depth direction. 
     By positioning the bracket  50  (and the radar unit  60  fixed thereto) relative to the lamp housing  20  (and the outer lens  30 ) as described above, the accuracy of the attachment of the radar unit  60  is improved. 
     Further, the gasket  70  is disposed between the rectangular ring-shaped part  51  and the vertical wall part  22 , which are opposed to each other, as described above. As a result, the lamp chamber S 1  in kept in a hermetically closed state. 
     Next, a procedure for replacing the radar unit  60  will be described. 
     Firstly, the screws N 1  (see  FIG.  7   ) are removed (i.e., unscrewed) and the bracket  50  is removed from the lamp housing  20 . As a result, the radar unit  60  is exposed. Next, the radar unit  60  is removed from the bracket  50  and replaced by another radar unit  60 . When doing so, since the radar unit  60  is detachably fixed to the bracket  50  (the radar-unit holding part  55 ) by the screws N 2  (see  FIG.  6   ), the radar unit  60  can be easily replaced by another radar unit  60 . 
     As explained above, according to this embodiment, the radar unit  60  can be replaced without replacing the whole vehicular lamp fitting  10 . 
     This is because the radar unit  60  is detachably fixed to the bracket  50  (radar-unit holding part  55 ). The bracket  50  is detachably fixed to the lamp housing  20  in a state that the extension part  54  is arranged in the lamp chamber S 1  and the rectangular ring-shaped part  51  and the flange part  52  close a through hole  21  formed in the lamp housing  20 . 
     Further, according to this embodiment, the bracket  50  to which the radar unit  60  is detachably fixed can be attached to the lamp chamber S 1  from the rear side of the lamp housing  20 . Further, according to this embodiment, since the radar unit  60  can be replaced by removing the bracket  50  to which the radar unit  60  is detachably fixed from the rear side of the lamp housing  20 , maintenance at the time of failure of the radar unit  60  can be performed. 
     Next, a modified example will be described. 
       FIG.  8    shows a modified example of the vehicular lamp fitting  10 . 
     As shown in  FIG.  8   , a positioning rib  25 , which abuts against the tip (the bottom part) of the extension part  54  of the bracket  50 , is provided in a lamp housing  20 A according to this modified example. The rest of the structure is similar to that of the vehicular lamp fitting  10  according to the above-described embodiment (see  FIG.  3   ). 
     According to this modified example, since the tip (the bottom part) of the extension part  54  of the bracket  50  is supported in the positioned state by the positioning rib  25 , it is possible to prevent (or suppress) the tip of the extension part  54  of the bracket  50  (i.e., the radar unit  60  fixed to the tip of the extension part  54 ) from being displaced due to its own weight. In this way, it is possible to prevent (or suppress) the radar unit  60  from being displaced due to its own weight and thereby to prevent (or suppress) the detection area of the radar unit  60  from being significantly changed. 
     Further, according to this modified example, the tip (the bottom part) of the extension part  54  of the bracket  50  is supported in the positioned state by the positioning rib  25 . Therefore, even if the vehicle (not shown) on which the vehicular lamp fitting  10  is mounted vibrates (For example, vibration during driving), it is possible to prevent (or suppress) the tip end portion of the extension part  54  of the bracket  50  (the radar unit  60  fixed to the tip end portion) from vibrating to largely fluctuate the detection area of the radar unit  60 . 
       FIG.  9    is another modified example of the vehicular lamp fitting  10 . This vehicular lamp fitting  10  according to this modified example will be referred to as a vehicular lamp fitting  10 A hereinafter. 
     In the above-described embodiment, an example in which the through hole  21  formed in the lamp housing  20  is a through hole that connects the rear surface of the lamp housing  20  to the lamp chamber S 1  (i.e., extends from the rear surface of the lamp housing  20  to the lamp chamber S 1 ) was described. However, the present disclosure is not limited to this example. For example, as shown in  FIG.  9   , the through hole  21  formed in the lamp housing  20  may be a through hole that connects the lower surface of the lamp housing  20  to the lamp chamber S 1  (i.e., extends from the lower surface of the lamp housing  20  to the lamp chamber S 1 ). 
     In this modified example, the bracket  50 A, to which the radar unit  60  is detachably fixed, is inserted into the lamp chamber S 1  through the through hole  21  formed in the lamp housing  20  (see an arrow in  FIG.  9 A ), and is detachably fixed to the lamp housing  20  by screws N 2  in a state in which the flange part  52 A of the bracket  50 A and the lamp housing part around the through hole  21  formed in the lamp housing  20  are opposed to each other with the gasket  70  interposed therebetween (see  FIG.  9 B ). 
     When doing so, as shown in  FIG.  9 B , a positioning rib  57  provided in the upper part of the bracket  50 A is inserted into a positioning recess  26  provided in the lamp housing  20 . In this way, the radar unit  60  is positioned relative to the outer lens  30 . Note that the positioning rib  57  may be provided in the lamp housing  20  and the positioning recess  26  may be provided in the bracket  50 A. 
     According to this modified example, the bracket  50  to which the radar unit  60  is detachably fixed can be attached to the lamp chamber S 1  from the underside of the lamp housing  20 . Further, according to this embodiment, since the radar unit  60  can be replaced by removing the bracket  50  to which the radar unit  60  is detachably fixed from the underside of the lamp housing  20 , maintenance at the time of failure of the radar unit  60  can be performed. 
     Note that although it is not shown in the drawings, the through hole  21  formed in the lamp housing  20  may be a through hole that connects a surface of the lamp housing  20  other than the rear and lower surfaces thereof, such as the upper surface (or a side surface) of the lamp housing  20 , to the lamp chamber S 1 . 
     Further, in the above-described embodiment, an example in which a through hole having a rectangular outer shape is used as the through hole  21  formed in the lamp housing  20 , and a bracket including a rectangular ring-shaped part  51  is used as the bracket  50 . However, the present disclosure is not limited to this example. For example, a through hole having a polygonal shape other than the rectangular shape may be used as the through hole  21  formed in the lamp housing  20 , and a bracket including a ring-shaped part having a polygonal shape other than the rectangular shape may be used as the bracket  50 . Further, for example, a through hole having a shape other than the polygonal shape (e.g., a circular shape or an elliptic shape) may be used as the through hole  21  formed in the lamp housing  20 , and a bracket including a ring-shaped part having a shape other than the polygonal shape (e.g., a circular shape or an elliptic shape) may be used as the bracket  50 . 
     Further, although an example in which a vehicular lamp fitting according to the present disclosure is applied to a rear combination lamp has been described in the above-described embodiment, the present disclosure is not limited to this example. For example, the present disclosure may be applied to a vehicle signal lighting fixture other than the rear combination lamp, and may also be applied to other vehicular lamp fittings such as a vehicle front light (e.g., a headlight). Note that when a vehicular lamp fitting according to the present disclosure is applied to a vehicle front light, a cooling fan is preferably disposed in the lamp chamber S 1 . 
     All the numeral values mentioned in the above-described embodiments are merely examples, and numeral values different from them can be uses as appropriate. 
     The above-described embodiments are merely examples in all the aspects thereof. The present disclosure should not be limited by the descriptions of the above-described embodiments. The present disclosure may be carried out in various other forms without departing from the spirit or main features of the disclosure.