Abstract:
A light guide member has a main body formed of material having translucency. The main body extends from a first end to a second end in an extending direction. The first end is configured to have light from a light source enter. A vertical cross-section of the main body in a plane perpendicular to the extending direction is formed in a shape of a fan.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application claims the benefit of priority of Japanese Patent Application No. 2010-257479, filed on Nov. 18, 2010. The disclosure of this application is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a light guide member, and particularly to a light guide member which light of a light source enters from at least one end portion thereof. 
         [0004]    2. Related Art 
         [0005]    Recently, as a light source having a high directivity such as a LED is being developed, application of a light guide member which transmits internally incident light from such the light source and emits its light from an end portion or a side surface thereof is also increasing. Here, there has been known a light guide rod which is used for illumination by emitting incident light from one end from a side surface (refer to, for example, Patent Document 1). 
       PATENT DOCUMENT 
       [0000]    
       
         [Patent Document 1] JP-A-2001-281457 
       
     
       SUMMARY 
       [0007]    In the case that a light guide member is utilized as, for example, a light source for decoration, it is important to enhance a decorative effect of the light guide member in a state where a light source is turned on, and further an external appearance of the light guide member in a state where incidence of the light from the light source is released, such as a state where the light source is turned off, is also important to the design. However, in the above Patent Document, consideration is not given to the external appearance of the light guide rod when the light source is turned off. 
         [0008]    One or more embodiments of the present invention provide a light guide member which can enhance a decorative effect of the light guide member also in a state where light incidence is released. 
         [0009]    A light guide member according to one or more embodiments of the invention is formed of material having translucency so as to extend from one end where light from a light source is to enter to the other end, wherein a vertical section to the extending direction is formed in the shape of a fan. 
         [0010]    According to this aspect, the incident light from a curved surface which becomes a curved portion of the fan-shaped section can be reflected by two surfaces which become two straight-line portions of the fan-shaped section and then can be emitted again from the curved surface. Therefore, also in a state where the light incidence from the light source is released, it is possible to make the light guide member appear to be plated when the light guide member is viewed from the curved surface, so that a decorative effect of the light guide member can be enhanced. 
         [0011]    According to one or more embodiments of the present invention, two straight-line portions in the fan-shaped section may cross each other at substantially right angles. 
         [0012]    According to this aspect, the two surfaces corresponding to the two straight-line portions reflect the incident light from the curved surface of the light guide member, thereby to enable substantially total reflection in the opposite direction to the incident direction toward the curved surface. Therefore, it is possible to make the light guide member appear to be plated more distinctively when the light guide member is viewed from the curved surface, so that external appearance of the light guide member can be enhanced more. 
         [0013]    According to one or more embodiments of the present invention, plural recess portions may be provided scatteringly in at least one of two surfaces which become the two straight-line portions of the fan-shaped section. 
         [0014]    In the case that the recess portions are provided in at least one of these two surfaces, the light guide member, viewed from the curved surface side, looks conversely, as if convex portions were provided. From a result of inventor&#39;s research and development, it has become clear that: by thus making the plural recess portions scatter in at least one of the two surfaces which become the two straight-line portions of the fan-shaped section, when light enters the light guide member from at least one end portion, reflection images of the plural recess portions appear in three-dimensional relief in the light guide member. Therefore, according to this aspect, the decorative effect of the light guide member when the light enters can be enhanced. 
         [0015]    According to one or more embodiments of the present invention, the plural recess portions may be provided in both of the two surfaces so as to be located asymmetrically around a line of intersection between the two surfaces. 
         [0016]    In the case that the plural recess portions are provided so as to be located symmetrically about the line of intersection between the two surfaces, there is fear that the recess portions located symmetrically may mutually disturb reflection of their images toward the curved surface. According to this aspect, it is possible to prevent the recess portions from thus mutually disturbing the reflection of their images, so that it is possible to make the plural recess portions when viewed from the curved surface side appear properly in relief and look like the plural convex portions. 
         [0017]    According to one or more embodiments of the invention, it is possible to enhance a decorative effect of a light guide member also in a state where light incidence is released. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a diagram showing a vehicle door on which an illumination unit according to one or more embodiments of the present invention is mounted. 
           [0019]      FIG. 2  is a front view of the illumination unit. 
           [0020]      FIG. 3  is a sectional view of the illumination unit taken along a line of P-P in  FIG. 2 . 
           [0021]      FIG. 4  is a diagram of a light guide member, viewed from a point Q in  FIG. 3 . 
           [0022]      FIG. 5  is a picture of the light guide member taken from a front side when the LED light source is in the off-state. 
           [0023]      FIG. 6  is a picture of the light guide member taken from the front side when the LED light source is in the On-state. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring to drawings, embodiments of the invention will be described below in detail. In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. 
         [0025]      FIG. 1  is a diagram showing a vehicle door  12  on which an illumination unit  10  according to one or more embodiments of the present invention is mounted. The door  12  is opened and closed when a vehicle occupant gets into or out of a vehicle.  FIG. 1  shows the inside of the door  12  seen from the room inside of the vehicle. 
         [0026]    The illumination unit  10  functions as a decorative lamp in the vehicle room. The illumination unit  10  is provided below a window  14  so as to extend in the substantially horizontal direction. Further, the application of the illumination unit  10  is not limited to the decorative lamp of the vehicle door. The illumination unit  10  may be provided in a lamp room of, for example, a headlamp or a rear combination lamp, or may be provided for others than the vehicle. 
         [0027]      FIG. 2  is a front view of the illumination unit  10 . The illumination unit  10  includes a light guide member  20 , a LED (Light Emitting Diode) light source  22 , and an attachment bracket  24 . The light guide member  20  is formed of material having translucency and elongated. Specifically, the light guide member  20  is formed of resin material which is colorless and transparent. The light guide member  20  may be formed of material which is colored and transparent, and also may be formed of glass. 
         [0028]    The light guide member  20  is formed so as to curve slightly in response to the interior design of the door  12 . Further, the light guide member  20  may be provided so as to extend linearly or in the shape of a ring, and also may be formed in other curved shapes. 
         [0029]    Two LED light sources  22  are provided, each of which is arranged so as to be opposed to each of both end faces  20   a  of the light guide member  20 . Because the illumination unit  10  is used for decoration, each of the LED light sources  22  to be used emits the colored light such as blue light. Further, a LED light source  22  which emits white light may be used. Because the LED light source  22  is known, description of the constitution thereof will be omitted. Further, light sources other than the LED light source  22 , such as an incandescent lamp and a discharge lamp may be used. The attachment bracket  24 , in order to fix the light guide member  20  to the door  12 , is attached onto a rear surface of the light guide member  20 . 
         [0030]    The number of the LED light sources  22  to be provided may be one. In this case, the LED light source  22  is arranged so as to be opposed to one of the two end faces  20   a , and the light guide member  20  is formed so as to extend from one end portion where the light from the LED light source  22  is to enter to the other end. 
         [0031]      FIG. 3  is a sectional view of the illumination unit  10  taken along a line of P-P in  FIG. 2 . As shown in  FIG. 3 , the light guide member  20  is formed so that a vertical section to its extending direction is fan-shaped. Accordingly, the light guide member  20  includes a surface  20   b  of a curved surface which becomes a curvilinear portion of the fan-shaped section, and two rear surfaces  20   c  which become two straight-line portions of the fan-shaped section. By thus forming the light guide member  20  so as to have the fan-shaped section, the incident light from the surface  20   b  can be reflected by the two rear surfaces  20   c  and can be emitted from the surface  20   b  again. Therefore, also in the case that the light guide member  20  has been turned off, because the light guide member  20  appears to be plated when seen from the front side, that is, from the surface  20   b  side, a decorative effect of the light guide member  20  can be enhanced. 
         [0032]    Further, in one or more embodiments of the present invention, the light guide member  20  is formed so that the two straight-line portions in the fan-shaped section cross each other at substantially right angles. Namely, the two rear surfaces  20   c  are formed so as to cross each other at a line of intersection  20   e  at substantially right angles. Hereby, by reflecting the incident light from the surface  20   b  of the light guide member  20  by these two rear surfaces  20   c  as shown by an arrow X in  FIG. 3 , substantially total reflection in the opposite direction to the incident direction is permitted. By providing the light guide member  20  so that such the total reflection of the incident light occurs in the opposite direction to the incident direction, the light guide member  20  appears clearly to be plated when seen from the surface  20   b , so that the decorative effect of the light guide member  20  can be enhanced more. Further, the angle between the two rear surfaces  20   c  is not limited to 90 degrees. The angle between the two rear surfaces  20   c  may be a predetermined angle smaller or larger than 90 degrees. 
         [0033]    Each of the two rear surfaces  20   c  is not subjected to mirror-like finishing such as aluminum or silver deposition. This is because: even in the case that such the mirror finishing is carried out, it is possible, by forming the section of the light guide member  20  in the fan shape as described above, to permit the total reflection of the incident light from the surface  20   b  by the two rear surfaces  20   c.    
         [0034]    The attachment bracket  24  is formed, in order to come into contact with the two rear surfaces  20   c  of the light guide member  20 , so that its section vertical to the extending direction is V-shaped. The attachment bracket  24  is formed of a resin. Further, the attachment bracket  24  may be formed of other material than the resin, such as metal. 
         [0035]      FIG. 4  is a diagram of the light guide member  20 , viewed from a point Q in  FIG. 3 . In each of the two rear surfaces  20   c , plural punctures  20   d  which are recess portions are provided so as to be scattered. In one or more embodiments of the present invention, each of the plural punctures  20   d  is formed so as to be recessed conically. Further, the shape of the puncture  20   d  is not limited to this shape. 
         [0036]    In the case that the punctures  20   d  which are the recess portions are provided in these two rear surfaces  20   c , the light guide member  20  looks, when seen from the surface  20   b  side, as if convex portions were conversely provided in the rear surfaces  20   c . By thus providing the punctures  20   d  in the rear surfaces  20   c , the light from the LED light source  22  is reflected by these punctures  20 , and it is possible to make the punctures  20   d  look like convex portions which are emitting light. Therefore, a high decorative effect can be obtained. 
         [0037]    In a result of research and development by this inventor, it has been confirmed that: by making the punctures  20   d  thus scattered in each of the two rear surfaces  20   c  which become the two straight-line portions of the fan-shaped section, when the LED light source  22  is turned on and light enters the light guide member  20 , each of the plural punctures  20   d  reflects its incident light, and appears in three-dimensional relief in the light guide member  20  as if the plural convex portions emitted the light. Therefore, by providing such the plural punctures  20   d , the decorative effect of the light guide member  20  when the light enters from the end face  20   a  can be enhanced. 
         [0038]    The plural punctures  20   d  are provided in both of the two rear surfaces  20   c  so as to be located asymmetrically about the line of intersection  20   e . In the case that plural punctures  20   d  are provided so as to be located symmetrically about the line of intersection  20   e  between the two rear surfaces  20   c , there is fear that the punctures  20   d  located symmetrically may mutually disturb reflection of their reflection images. By thus arranging the plural punctures  20   d  so as to be located asymmetrically about the line of intersection  20   e , it is possible to prevent the punctures  20   d  from mutually disturbing the reflection of their images, so that it is possible to make the reflection images of the plural punctures  20   d  appear in relief. Further, the plural punctures  20   d  may be provided on either of the two rear surfaces  20   c  so as to be scattered. 
         [0039]    In one or more embodiments of the present invention, the plural punctures  20   d  are arranged so as to line up regularly in positions of intersection points of a square lattice when the images inverted around the intersection line  20   e  are superimposed. Further, the arrangement of the plural punctures  20   d  is not limited to the above arrangement but the plural punctures  20   d  may be arranged irregularly. 
         [0040]      FIG. 5  is a picture of the light guide member  20  taken from a front side when the LED light source  22  is in the off-state. As shown in  FIG. 5 , although the LED light source  22  is in the off-state and further the rear surface  20 C is not subjected to the mirror-like finishing, the light guide member  20  reflects the light from the outside and glitters. Accordingly, it is possible to give a user a look of the light guide member  20  as if the light guide member  20  was plated, so that the high decorative effect can be obtained also when the LED light source  22  is in the off-state. 
         [0041]      FIG. 6  is a picture of the light guide member  20  taken from the front side when the LED light source  22  is in the On-state. As shown in  FIG. 6 , when the LED light source  22  is lighting, it is possible to make the reflection images by the plural punctures  20   d  appear in three-dimensional relief inside the light guide member  20 . Therefore, also when the LED light source  22  is lighting, the high decorative effect can be obtained. 
         [0042]    Although the invention has been described with respect to the foregoing embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, other implementations are within the scope of the claims. 
         [0043]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.