Abstract:
This transparent shield device has a windshield that is disposed in the sensing direction of an onboard camera. The windshield has an outer surface that is exposed to the outside. The outer surface has an extended imaging area, which includes the imaging area of the onboard camera, and a surrounding area. Furthermore, the transparent shield device has a water-repellent sticker that is positioned within the extended imaging area and/or a water-attracting coating layer that is positioned within the surrounding area. Liquid droplets deposited on the outer surface can be moved out of the imaging area or prevented from entering the imaging area from the surrounding area.

Description:
RELATED APPLICATIONS 
       [0001]    The present application in a National Phase entry of PCT Application No. PCT/JP2014/080652, filed Nov. 19, 2014, which claims priority to Japanese Patent Application No. 2014-003532, filed Jan. 10, 2014 and Japanese Patent Application No. 2014-060454 filed Mar. 24, 2014, all of said applications being hereby incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a transparent shield device, a camera device, and a transparent sticker. 
         [0003]    The number of vehicles provided with an on-vehicle camera such as a drive recorder arranged at the inner side of a windshield (front windshield) has increased (refer to, for example, Patent Document 1). 
         [0004]    Such a vehicle is capable of recording, for example, the situation outside the vehicle when an accident occurs. 
       PRIOR ART DOCUMENT 
     Patent Document 
       [0005]    Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-195235 
       SUMMARY OF THE INVENTION 
       [0006]    However, when an on-vehicle optical sensor such as the above on-vehicle camera is arranged at the inner side of the windshield to sense the situation outside the windshield, due to the raindrops that move along the windshield during rain, the detection results (images when on-vehicle camera is used) that are obtained may not be satisfactory. 
         [0007]    In particular, when the entire windshield has undergone a water-repellent treatment, many raindrops moving downwardly pass through a sensing zone when the vehicle is traveling at a low speed, and many raindrops moved upwardly by the wind produced when the vehicle is traveling at a high speed pass through the sensing zone. As a result, satisfactory detection results often cannot be obtained. 
         [0008]    In the same manner, the field of view is obstructed by raindrops moved upwardly along the windshield of the vehicle when the vehicle is traveling at a high speed even when using the windshield wipers during rain (in particular, when the entire windshield has undergone a water-repellent treatment). The field of view is also obstructed by rain that falls from the vehicle roof when the brakes are applied. Thus, it is desired that the field of view be further ensured. 
         [0009]    It is an object of the present invention to provide a transparent shield device, a camera device, and a transparent sticker that allow for satisfactory recognition of information outside a vehicle from the inner side of a windshield even in rain. 
         [0010]    A transparent shield device that solves the above problem includes a transparent member arranged in a sensing direction of an optical sensor. The transparent member includes an outer surface exposed to an outer side. The outer surface includes an enlarged sensing zone including a sensing zone of the optical sensor and a surrounding zone located at a further outer side of the enlarged sensing zone. The transparent shield device further includes at least one of a water-repellent portion, which is water-repellent and located in the enlarged sensing zone, and a hydrophilic portion, which is hydrophilic and located in the surrounding zone. Movement of a water drop on the outer surface is allowed from the sensing zone to an outer side of the sensing zone or restricted from the surrounding zone into the sensing zone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front view showing a transparent shield device according to a first embodiment of the present invention. 
           [0012]      FIG. 2  is a partial cross-sectional view of the transparent shield device shown in  FIG. 1 . 
           [0013]      FIG. 3  is a partially enlarged front view showing a transparent shield device of another example. 
           [0014]      FIG. 4  is a partially enlarged front view showing a transparent shield device of a further example. 
           [0015]      FIG. 5  is a partially enlarged front view showing a transparent shield device of a further example. 
           [0016]      FIG. 6  is a partial cross-sectional view showing a transparent shield device of a further example. 
           [0017]      FIG. 7  is a partially enlarged front view showing a transparent shield device of a further example. 
           [0018]      FIG. 8  is a front view showing a transparent shield device of a further example. 
           [0019]      FIG. 9  is a front view showing a transparent shield device according to a second embodiment of the present invention. 
           [0020]      FIG. 10  is a partial cross-sectional view of the transparent shield device shown in  FIG. 9 . 
           [0021]      FIG. 11  is a schematic cross-sectional view of the conveying force of a raindrop applied by a hydrophilic portion and a water-repellent portion shown in  FIG. 9 . 
           [0022]      FIG. 12  is a partially enlarged front view showing a vehicle windshield of a further example. 
           [0023]      FIG. 13  is a perspective view showing a camera device. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    A first embodiment of a transparent shield device will now be described with reference to  FIGS. 1 and 2 . 
         [0025]    As shown in  FIGS. 1 and 2 , an on-vehicle optical sensor-added vehicle  1  (hereinafter referred to simply as vehicle) includes a windshield G, which serves as a transparent member including an outer surface exposed to the outside. 
         [0026]    Further, in the vehicle  1 , an on-vehicle camera  2  (in this example, drive recorder), which serves as an on-vehicle optical sensor that captures images of and stores (records) vehicle exterior information (for example, situation), is arranged at the inner side of the windshield G. The on-vehicle camera  2  of the present embodiment is located at the upper laterally (horizontally) middle portion of the windshield G. The on-vehicle camera  2  is directed toward a portion of the windshield G that is not wiped by a vehicle windshield wiper. The on-vehicle camera  2  is located between a rearview mirror (not shown) and the windshield G. The on-vehicle camera  2  captures images of and records the situation outside the windshield G. 
         [0027]    The outer surface of the windshield G is exposed to the outside. The outer surface includes an image capturing zone H 1 , which is a sensing zone of the on-vehicle camera  2 , an enlarged image capturing zone H 2 , which is an enlarged sensing zone, and a surrounding zone H 3 , which is located at the outer side of the enlarged image capturing zone H 2  (refer to  FIG. 2 ). The enlarged image capturing zone H 2  entirely includes the image capturing zone H 1  on the outer surface of the windshield G and is slightly wider than the image capturing zone H 1 . The surrounding zone H 3  surrounds the enlarged image capturing zone H 2 . In the first embodiment, the surrounding zone H 3  is located at the upper and lower sides of the enlarged image capturing zone H 2 . Stickers  3  and  4 , which serve as hydrophilic portions having hydrophilicity, are applied to the surrounding zone H 3 . The stickers  3  and  4  are colorless and transparent. The outer surfaces of the stickers  3  and  4  have a higher hydrophilicity than the outer surface of the windshield G where the stickers  3  and  4  are not applied. In the present embodiment, a water-repellent treatment is performed on the entire windshield G in advance by applying a water-repellent coating layer  5  to the entire windshield G. The stickers  3  and  4  are applied to the coating layer  5 . That is, in the present embodiment, portions of the outer surface of the windshield G, excluding where the stickers  3  and  4  are applied, function as water-repellent portions that repel water. 
         [0028]    The sticker  3  is located at the upper side of the image capturing zone H 1 . The sticker  3  includes a lateral (horizontal) middle portion, two lateral ends, and downwardly inclined portions  3   a  and  3   b.  The downwardly inclined portions  3   a  and  3   b  are respectively inclined downwardly from the middle portion toward the two ends. More specifically, the sticker  3  of the present embodiment includes the downwardly inclined portion  3   a,  which is inclined downwardly from the middle portion toward a first end, and the downwardly inclined portion  3   b,  which is inclined downwardly from the middle portion toward a second end. 
         [0029]    The sticker  4  is located at the lower side of the image capturing zone H 1 . The sticker  4  includes a lateral (horizontal) middle portion, two lateral ends, and upwardly inclined portions  4   a  and  4   b.  The upwardly inclined portions  4   a  and  4   b  are respectively inclined upwardly from the middle portion toward the two ends. More specifically, the sticker  4  of the present embodiment includes the upwardly inclined portion  4   a,  which is inclined upwardly from the middle portion toward a first lateral end, and the upwardly inclined portion  4   b,  which is inclined upwardly from the laterally middle portion toward a second lateral end. 
         [0030]    The operation of the transparent shield device will now be described. For example, when the vehicle is traveling at a low speed in rain, raindrops fall from the upper side of the upper sticker  3  into the image capturing zone H 1  (front of on-vehicle camera  2 ). When reaching the sticker  3 , the raindrops are guided to the laterally outer side mainly by the downwardly inclined portions  3   a  and  3   b  because of the hydrophilicity of the surface of the sticker  3 . As a result, the raindrops flow out of the image capturing zone H 1  (refer to arrow A shown by broken line in  FIG. 1 ). 
         [0031]    Further, when the vehicle is traveling at a high speed in rain, raindrops are blown upwardly by wind and enter the image capturing zone H 1  (front of on-vehicle camera  2 ) from the lower side of the lower sticker  4 . When reaching the sticker  4 , the raindrops are guided to the laterally outer side mainly by the upwardly inclined portions  4   a  and  4   b  because of the hydrophilicity of the surface of the sticker  4 . As a result, the raindrops flow out of the image capturing zone H 1  (refer to arrow B shown by broken line in  FIG. 1 ). 
         [0032]    The above embodiment has the advantages described below. 
         [0033]    (1) The windshield G includes the outer surface that is exposed to the outside. The outer surface includes the enlarged image capturing zone H 2 , which includes the image capturing zone H 1  of the on-vehicle camera  2 , and the surrounding zone H 3 , which is located further outwardly from the enlarged image capturing zone H 2 . The water-repellent coating layer  5  is located in the enlarged image capturing zone H 2 , and the hydrophilic stickers  3  and  4  are located in the surrounding zone. The water-repellent coating layer  5  allows raindrops on the outer surface of the windshield G to move out of the image capturing zone H 1 . Further, the hydrophilic stickers  3  and  4  limit the entrance of raindrops on the outer surface of the windshield G into the image capturing zone H 1  from the surrounding zones H 3 . 
         [0034]    More specifically, for example, the upper sticker  3  located outside the image capturing zone H 1  reduces raindrops that fall from above the sticker  3  and enter the image capturing zone H 1 . Further, for example, the lower sticker  4  located outside the image capturing zone H 1  reduces raindrops blown upwardly by wind from below the sticker  3  and enter the image capturing zone H 1 . Thus, the passage of raindrops through the image capturing zone H 1  of the on-vehicle camera  2  is limited even when it is raining. This allows the on-vehicle camera  2  to detect (capture images of) vehicle exterior information in a satisfactory manner. 
         [0035]    (2) The upper sticker  3  located outside the image capturing zone H 1  includes the downwardly inclined portions  3   a  and  3   b,  which are inclined downwardly from the middle portion toward the two ends. This allows raindrops that fall from above and reach the sticker  3  to be guided to the laterally outer side by the downwardly inclined portions  3   a  and  3   b.  Thus, raindrops smoothly flow out of the image capturing zone H 1 . 
         [0036]    (3) The upper sticker  4  located outside the image capturing zone H 1  includes the upwardly inclined portions  4   a  and  4   b,  which are inclined upwardly from the middle portion toward the two ends. This allows raindrops that are blown upwardly by wind from below and reach the sticker  4  to be guided to the laterally outer side by the upwardly inclined portions  4   a  and  4   b.  Thus, raindrops smoothly flow out of the image capturing zone H 1 . 
         [0037]    (4) Since the stickers  3  and  4  having the hydrophilic outer surfaces are used as hydrophilic portions, the hydrophilic portions may easily be arranged on (need only be applied to) the windshield G. 
         [0038]    The first embodiment may be modified as follows. 
         [0039]    In the first embodiment, the transparent shield device includes the stickers  3  and  4 , which serve as hydrophilic portions, and a water-repellent treatment is performed on the entire windshield G. Instead, the transparent shield may have a different shape. 
         [0040]    For example, the hydrophilic portions may be changed as shown in  FIG. 3 . The hydrophilic portions of this example are hydrophilic coating layers  11  and  12 . The windshield G is coated by a coating agent to form the coating layers  11  and  12 . In such a case, the upper coating layer  11  reduces raindrops that fall from above and enter the image capturing zone H 1  (front of on-vehicle camera  2 ). Further, the lower coating layer  12  reduces raindrops blown upwardly by wind from below and enter the image capturing zone H 1  (front of on-vehicle camera  2 ). In addition, since the coating layers  11  and  12  are hydrophilic, the hydrophilic portions are easily arranged just by applying or spraying a coating agent. 
         [0041]    For example, as shown in  FIG. 4 , the hydrophilic portion may be omitted leaving only the water-repellent portion. The water-repellent portion of this example is arranged only in the enlarged image capturing zone H 2  and not on the entire outer surface of the windshield G. In the same manner as the first embodiment, the water-repellent portion is the water-repellent coating layer  5 . 
         [0042]    For example, as shown in  FIG. 5 , the transparent shield device may include the hydrophilic coating layers  11  and  12  of  FIG. 3  and the water-repellent coating layer  5  of  FIG. 4 . 
         [0043]    For example, as shown in  FIG. 6 , the water-repellent portion may be a water-repellent sticker  15 . The sticker  15  is colorless and transparent. The outer surface of the sticker  15  has a higher water-repellency than the outer surface of the windshield G where the sticker  15  is not applied. In  FIG. 6 , the stickers  3  and  4  serve as hydrophilic portions. Instead, the hydrophilic portions may be the coating layers  11  and  12  shown in  FIG. 3 . 
         [0044]    In the above embodiment, the stickers  3  and  4 , which serve as hydrophilic portions, include the downwardly inclined portions  3   a  and  3   b  and the upwardly inclined portions  4   a  and  4   b.  However, the hydrophilic portions are not limited to such shape and may be changed in shape. For example, as shown in  FIG. 7 , the hydrophilic portions may respectively extend straight in the lateral direction (horizontal direction) of the vehicle. The stickers  3  and  4  serve as the hydrophilic portions in  FIG. 7 . However, the hydrophilic portions may be the coating layers  11  and  12 . The coating layer  5  serves as the water-repellent portion in  FIG. 7 . However, the water-repellent portion may be the sticker  15 . 
         [0045]    The hydrophilic portions (stickers  3  and  4 ) of the first embodiment may be changed in shape so that the upper hydrophilic portion and the lower hydrophilic portion, which are located outside the image capturing zone H 1 , are connected to each other at the laterally outer side of the image capturing zone H 1 . For example, a circular hydrophilic portion may surround the image capturing zone H 1 . In this example, the surrounding zone H 3  includes a first side (right) and a second side (left) of the image capturing zone H 1  in addition to the upper side and the lower side of the image capturing zone H 1 . 
         [0046]    In the first embodiment, the stickers  3  and  4 , which are hydrophilic and serve as hydrophilic portions, are located at an upper position and a lower position outside of the image capturing zone H 1 . Instead, the first embodiment may include only one of the hydrophilic portions. 
         [0047]    In the first embodiment, the present invention is applied to a structure in which the on-vehicle camera  2  is located at the inner side of the windshield G. However, the present invention is not limited to this structure. For example, in a vehicle that includes the on-vehicle camera at the inner side of a rear window, the rear window may include at least one of the hydrophilic portion or the water-repellent portion. In such a case, it is less likely that raindrops are upwardly moved from below by wind even when the vehicle is traveling at a high speed. Thus, a sufficient effect is obtained even when the hydrophilic portion is located only at the upper outer side of the image capturing zone. Alternatively, a sufficient effect may be obtained even when just arranging the water-repellent portion in the image capturing zone. 
         [0048]    In the first embodiment, the present invention is applied to a structure in which the on-vehicle optical sensor is the on-vehicle camera  2 . However, the present invention is not limited to this structure. For example, the hydrophilic portions may be arranged on the windshield G in a vehicle in which the inner side of the windshield G includes a radar that measures the distance to a front vehicle, which is vehicle exterior information, or an on-vehicle optical sensor using laser light, of which the sensing results are adversely affected by water drops. 
         [0049]    In the first embodiment and the modified examples, the present invention is applied to examples that include an on-vehicle optical sensor. However, the present invention is not limited to such examples. A hydrophilic portion having hydrophilicity may be arranged in at least one of the upper side and the lower side of the outer surface of the windshield G to obtain a field of view for the vehicle occupants including the driver. 
         [0050]    For example, as shown in  FIG. 8 , the stickers  21  and  22 , which are hydrophilic and serve as hydrophilic portions, may be applied to the upper side and the lower side of the outer surface of the windshield G. 
         [0051]    In this example, the upper sticker  21  includes a laterally (horizontally) middle portion, two lateral ends, and downwardly inclined portions  21   a  and  21   b.  The downwardly inclined portion  21   a  is inclined downwardly from the middle portion toward a first end. The downwardly inclined portion  21   b  is inclined downwardly from the middle portion toward a second end. Further, the lower sticker  22  includes a laterally (horizontally) middle portion, two lateral ends, and upwardly inclined portions  22   a  and  22   b . 
         [0052]    The upwardly inclined portion  22   a  is inclined upwardly from the middle portion toward the first end. The upwardly inclined portion  22   b  is inclined upwardly from the middle portion toward the second end. 
         [0053]    In such a structure, for example, when the vehicle is traveling at a low speed or when the brakes are applied, raindrops fall from the upper side of the upper sticker  21  and move toward the middle of the windshield G (field of view). When reaching the sticker  21 , the raindrops are guided and outwardly moved to the laterally outer side mainly by the downwardly inclined portions  21   a  and  21   b  because of the hydrophilicity of the surface of the sticker  21  (refer to arrow C shown by broken line in  FIG. 8 ). 
         [0054]    Further, for example, when the vehicle is traveling at a high speed during rain, raindrops are moved by wind from the lower side of the lower sticker  22  toward the middle of the windshield G (field of view). When reaching the sticker  22 , the raindrops are guided and outwardly moved to the laterally outer side mainly by the upwardly inclined portions  22   a  and  22   b  because of the hydrophilicity of the surface of the sticker  22  (refer to arrow D shown by broken line in  FIG. 8 ). This reduces the raindrops that pass through the field of view of vehicle occupants, which include the driver, even during rain and allows the vehicle occupants to view the outside in a satisfactory manner. 
         [0055]    Further, in this example, the stickers  21  and  22  are arranged on the entire outer surface of the windshield G in the lateral direction. Instead, a sticker that serves as a hydrophilic portion having hydrophilicity may be arranged in at least one of the upper side and the lower side of the field of view (eye point) located in front of a driver seat. 
         [0056]    In such an example directed to the field of view of vehicle occupants, the hydrophilic portions may be formed by coating layers or changed in shape as described above. 
         [0057]    The hydrophilic portion and the water-repellent portion may be arranged in a location of the windshield G that is wiped by a vehicle windshield wiper. 
         [0058]    A second embodiment of a transparent shield device will now be described with reference to  FIGS. 9 to 11 . Like or same reference numerals are given to those components that are the same as the corresponding components of the first embodiment and thus will not be described. 
         [0059]    A sticker  33  is applied to a location of the outer surface of the windshield G that corresponds to the image capturing zone H 1  (refer to  FIG. 10 ), which is a sensing zone of the on-vehicle camera  2 . More specifically, the sticker  33  is applied to the enlarged image capturing zone H 2 . The outer surface of the sticker  33  includes a hydrophilic portion  34  (second hydrophilic portion) and a water-repellent portion  35 , which extend over a larger zone than the image capturing zone H 1 . The hydrophilic portion  34  has a higher hydrophilicity than the water-repellent portion  35 . The water-repellent portion  35  has a higher water-repellency than the hydrophilic portion  34 . In the sticker  33 , the area of the hydrophilic portion  34  gradually increases in a gravitational direction. In the sticker  33 , the area of the water-repellent portion  35  gradually decreases in the gravitational direction. In the present embodiment, the sticker  33  is tetragonal. The hydrophilic portion  34  extends straight in the gravitational direction as viewed from the front of the vehicle  1  along the outer surface of the windshield G as the width of the hydrophilic portion  34  gradually increases. The water-repellent portion  35 , which is a portion that excludes the hydrophilic portion  34 , extends straight in the gravitational direction as viewed from the front of the vehicle  1  along the outer surface of the windshield G as the width of the water-repellent portion  35  gradually decreases. In the present embodiment, the hydrophilic portion  34  and the water-repellent portion  35  of the sticker  33  are arranged in a predetermined pattern. The hydrophilic portion  34  and the water-repellent portion  35  of the sticker  33  are colorless and transparent. However, the hydrophilic portion  34  is shaded to facilitate visual understanding in the partially enlarged view of  FIG. 9 . Further, the sticker  33  is arranged prior to application to the windshield G so that the area of the hydrophilic portion  34  gradually increases in a certain direction and the area of the water-repellent portion  35  gradually decreases in the certain direction. The sticker  33  is applied to the windshield G so that the certain direction corresponds to the gravitational direction. It is preferred that water drops that are subject to removal come into contact with both the hydrophilic portion  34  and the water-repellent portion  35  to produce a conveying force acting on the water drops. Thus, it is preferred that the width of the hydrophilic portion  34  and the width of the water-repellent portion  35  be smaller than the diameter of the water drops (size of surface sticker  33  that contacts water drops). 
         [0060]    The operation of the above transparent shield device will now be described. 
         [0061]    For example, when raindrops are collected on the outer surface of the sticker  33  of the windshield G during rain, the action of the sticker  33  (conveying force F of water drops applied by hydrophilic portion  34  and water-repellent portion  35 ) and the gravitational force are applied so that the raindrops mainly flow in the gravitational direction. More specifically, as shown in  FIG. 11 , the sticker  33  (hydrophilic portion  34  and water-repellent portion  35 ) produces the conveying force F applied to a water drop E. That is, when the windshield G and the sticker  33  are horizontally arranged, a water drop E on the sticker  33  extends across the region where the hydrophilic portion  34  has a large area (lower side in  FIG. 9 ) and the region where the water-repellent portion  35  has a large area (upper side in  FIG. 9 ). In such a case, as shown in  FIG. 11 , a portion of the water drop E located in the region where the hydrophilic portion  34  has a large area has a contact angle θa relative to the sticker  33 , and a portion of the water drop E located in the region where the water-repellent portion  35  has a large area has a contact angle θb relative to the sticker  33 . Since the contact angle θa is smaller than the contact angle θb, the conveying force F acts on the water drop E toward the region where the hydrophilic portion  34  has a large area (right in  FIG. 11 ). In the present embodiment, the conveying force F acts in a direction that corresponds to the direction in which the gravitational force acts. Thus, raindrops mainly move in the gravitational direction. Although the windshield G is vertically shown in  FIG. 10 , the windshield G may be inclined. In such a case, a component force of the gravitational force and the conveying force F are applied so that raindrops move in the gravitational direction (more specifically, direction of component force of gravitational force on the surface on which windshield G is inclined). 
         [0062]    The second embodiment has the advantages described below. 
         [0063]    (5) The hydrophilic portion  34  (second hydrophilic portion) is hydrophilic and located in the enlarged image capturing zone H 2 . The water-repellent portion  35  of the enlarged image capturing zone H 2  has an area that gradually decreases in the gravitational direction. The hydrophilic portion  34  and the water-repellent portion  35  are arranged adjacent to each other. The hydrophilic portion  34  has an area that gradually increases in the gravitational direction. Thus, even when raindrops are collected on the outer surface of the sticker  33 , the raindrops easily flow in the gravitational direction because of the conveying force F, which is produced by the hydrophilic portion  34  and the water-repellent portion  35 , and the gravitational force. This limits situations in which raindrops remain on the outer surface of the windshield G in the sensing direction of the on-vehicle camera  2 . This allows the on-vehicle camera  2  to perform satisfactory detection, that is, image capturing. 
         [0064]    (6) The hydrophilic portion  34  and the water-repellent portion  35  (that is, sticker  33 ) are arranged over a zone in the outer surface of the windshield G that is larger than the image capturing zone H 1  of the on-vehicle camera  2 . This moves raindrops out of the image capturing zone H 1  of the on-vehicle camera  2 . Accordingly, the on-vehicle camera  2  is capable of performing satisfactory image capturing. 
         [0065]    (7) The hydrophilic portion  34  and the water-repellent portion  35  are arranged in a single sticker  33 . The sticker  33  is applied to the outer surface of the windshield G. This allows the hydrophilic portion  34  and the water-repellent portion  35  to be easily arranged on the windshield G. In particular, this is preferable when the hydrophilic portion  34  and the water-repellent portion  35  are both set in a predetermined pattern to form a single sticker  33 . 
         [0066]    The second embodiment may be modified as follows. 
         [0067]    The hydrophilic portion  34  and the water-repellent portion  35  of the second embodiment may be changed to shapes having other patterns as long as the conveying force F acts in the gravitational direction rather than the horizontal direction. 
         [0068]    For example, the sticker  33  may be changed to a sticker  43  shown in  FIG. 12 . A hydrophilic portion  41  (second hydrophilic portion) of this example extends obliquely toward the laterally outer side in the gravitational direction as viewed from the front of the vehicle  1  along the outer surface of the windshield G. The width of the hydrophilic portion  41  gradually increases toward the laterally outer side. A water-repellent portion  42 , which is a portion of the sticker  43  that excludes the hydrophilic portion  41 , extends obliquely toward the laterally outer side in the gravitational direction as viewed from the front of the vehicle  1 . The width of the water-repellent portion  42  gradually decreases toward the laterally outer side. In such a structure, when raindrops are collected on the outer surface, the hydrophilic portion  41  and the water-repellent portion  42  produce a conveying force that acts on raindrops obliquely toward the laterally outer side in the gravitational direction as viewed from the front of the vehicle  1 . As a result, the raindrops are easily moved in the gravitational direction by the conveying force F, which is produced by the hydrophilic portion  41  and the water-repellent portion  42 , and the gravitational force. In this example, the hydrophilic portion  41  and the water-repellent portion  42  of the sticker  43  are colorless and transparent. However, in  FIG. 12 , the hydrophilic portion  41  is shaded to facilitate visual understanding. 
         [0069]    In the above embodiment, the hydrophilic portion  34  ( 41 ) and the water-repellent portion  35  ( 42 ) are arranged in the single sticker  33  ( 43 ) and applied to the outer surface of the windshield G. However, the hydrophilic portion  34  ( 41 ) and the water-repellent portion  35  ( 42 ) are not limited to such a structure. For example, the hydrophilic portion may be a hydrophilic coating layer, and the water-repellent portion may be a water-repellent coating layer. A coating agent may be directly coated on the windshield G to form the hydrophilic coating layer and the water-repellent coating layer. The hydrophilic coating layer and the water-repellent coating layer may be easily arranged just by applying or spraying a coating agent. 
         [0070]    The hydrophilic portion only needs to have a higher hydrophilicity than the water-repellent portion. For example, just a hydrophilic portion having a high hydrophilicity may be applied to the original outer surface of the windshield G by a coating agent. In such a case, the original outer surface of the windshield G functions as the water-repellent portion. In contrast, the water-repellent portion only needs to have a higher water-repellency than the hydrophilic portion. For example, just a water-repellent portion having a high water-repellency may be applied to the original outer surface of the windshield G by a coating agent. In such a case, the original outer surface of the windshield G functions as the hydrophilic portion. 
         [0071]    In the above embodiment, the hydrophilic portion  34  and the water-repellent portion  35  (that is, sticker  33 ) are located in the enlarged image capturing zone H 2  on the outer surface of the windshield G. Instead, for example, the hydrophilic portion  34  and the water-repellent portion  35  may be located only around the central portion in the image capturing zone H 1  of the on-vehicle camera  2 . 
         [0072]    In the above embodiment, the present invention is applied to the structure including the on-vehicle camera  2 , which serves as an optical sensor, and the windshield G, which serves as a transparent member. However, the present invention is not limited to this structure. The optical sensor and the transparent member may be replaced with other members. 
         [0073]    The present invention may be applied to, for example, a camera device  51  (surveillance camera) that is arranged along a road or river. The camera device  51  includes a camera sensor  51   a,  which serves as an optical sensor and capture images of the outside, a glass window  51   b,  which serves as a transparent member and is exposed to the outside, and the sticker  33  (hydrophilic portion  34  and water-repellent portion  35 ) arranged on the glass window  51   b.  Such a structure limits situations in which water drops such as raindrops remain on the outer surface of the glass window  51   b  and allows for satisfactory image capturing. 
         [0074]    Further, the on-vehicle optical sensor may use radar or laser light that measures the distance to a front vehicle. The hydrophilic portion and the water-repellent portion may be arranged in a sensing direction of the radar or laser light and arranged at the transparent member exposed to the outside as described above. 
         [0075]    In addition, the on-vehicle camera  2  may be used as a side mirror camera that captures an image of the side of a vehicle or a rear camera that captures an image at the rear of a vehicle. 
       DESCRIPTION OF REFERENCE CHARACTERS 
       [0000]    
       
           1 : vehicle 
           2 : on-vehicle camera (optical sensor) 
           3 ,  4 ,  21 ,  22 : sticker (hydrophilic portion) 
           3   a,    3   b,    4   a,    4   b,    21   a,    21   b,    22   a,    22   b : inclined portion 
           5 : coating layer (water-repellent portion) 
           15 : sticker (water-repellent portion) 
           11 ,  12 : coating layer (hydrophilic portion) 
           33 ,  43 : sticker 
           34 ,  41 : hydrophilic portion 
           35 ,  42 : water-repellent portion 
           51 : camera device 
           51   a : camera sensor 
           51   b : glass window (transparent member) 
         E: water drop 
         F: conveying force 
         G: windshield (transparent member) 
         θa, θb: contact angle 
         H 1 : image capturing zone (sensing zone) 
         H 2 : enlarged image capturing zone (enlarged sensing zone) 
         H 3 : surrounding zone