Abstract:
An illuminated switch includes an operation knob that includes an operation surface, a light source that emits light beams using a predetermined direction as an optical axis, and a first light guide member that is provided in the operation knob and guides the light beams emitted from the light source to the operation surface. The first light guide member includes a light incident surface formed of inclined surface that refracts light beams entering along the optical axis in a first direction, a reflection surface that reflects light beams refracted at the light incident surface in a second direction different from the first direction, and a light exit surface that transmits light beams reflected by the reflection surface.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present invention contains subject matter related to Japanese Patent Application No. 2007-169076 filed in the Japanese Patent Office on Jun. 27, 2007, the entire contents of which being incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The preset invention relates to an illuminated switch including an illumination mechanism that illuminates a surface (operation surface) of an operation knob from inside. 
         [0004]    2. Related Art 
         [0005]    A switch device has been disclosed in Japanese Unexamined Patent Application Publication No. 2006-59561. The switch device includes a translucent indicator side guide and a light emitting material side guide, which are disposed to be separated from each other. The translucent indicator side guide is provided in an operation knob, and light beams enter the light emitting material side guide from a luminous body. In the switch device, light beams emitted from the luminous body reach the translucent indicator side guide from the light emitting material side guide, so that a translucent indicator is illuminated. 
         [0006]    Further, the invention relating to a switch of electrical equipment for an automobile has been disclosed in FIG. 6 of Japanese Unexamined Patent Application Publication No. 2000-100275. The switch propagates light beams emitted from a light source in a desired direction by disposing a triangular prism at a light emitting end of an optical path member. 
         [0007]    However, in the switch device disclosed in Japanese Unexamined Patent Application Publication No. 2006-59561, the directions of the light beams passing though the translucent indicator side guide are different from one another. For this reason, when being emitted from the translucent indicator side guide, light beams are apt to be dispersed in several directions. Therefore, there has been a problem in that the brightness deteriorates when an operator see the translucent indicator. 
         [0008]    Meanwhile, Japanese Unexamined Patent Application Publication No. 2000-100275 discloses a technology that solves the above-mentioned problem and propagates light beams emitted from the luminous body in a desired direction. However, there have been problems in that the amount of light is reduced at the peripheral portion of the light exit surface of the light guide member and the unevenness of brightness occurs. 
       SUMMARY 
       [0009]    According to an aspect of the disclosure, an illuminated switch includes an operation knob that includes an operation surface, a light source that emits light beams having an optical axis in a predetermined direction, and a first light guide member that is provided in the operation knob and guides the light beams emitted from the light source to the operation surface. The first light guide member includes a light incident surface formed of inclined surface that refracts light beams entering along the optical axis in a first direction, a reflection surface that reflects light beams refracted at the light incident surface in a second direction different from the first direction, and a light exit surface that transmits light beams reflected by the reflection surface. The light beams emitted from the light source are reflected by the reflection surface, and then exit from the light exit surface. Therefore, it is possible to provide a sufficient amount of light to the peripheral portion of the light exit surface and to prevent the unevenness of brightness of the light exit surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a cross-sectional view of an illuminated switch according to an embodiment. 
           [0011]      FIG. 2  is a perspective view of a first light guide member and a second light guide member. 
           [0012]      FIG. 3  is a cross-sectional view of the first light guide member and the second light guide member, as seen from above (in a Z2 direction). 
           [0013]      FIG. 4  is a cross-sectional view of the first light guide member and the second light guide member, as seen from the side (in an X2 direction). 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0014]      FIG. 1  is a cross-sectional view of an illuminated switch according to an embodiment.  FIG. 2  is a perspective view of a first light guide member and a second light guide member.  FIG. 3  is a cross-sectional view of the first light guide member and the second light guide member, as seen from above (in a Z2 direction).  FIG. 4  is a cross-sectional view of the first light guide member and the second light guide member, as seen from the side (in an X2 direction). 
         [0015]    Hereinafter, an optical axis, which passes through a light source  5  and is parallel to a Y axis, will be described as an optical axis L 1 . 
         [0016]    An illuminated switch  10  shown in  FIG. 1  is an operation switch used, for example, in a vehicle-mounted electronic device (such as an air conditioner), and includes an operation knob  11  that is provided so as to swing with respect to an electronic device body  9 . In  FIG. 1 , a front face of the electronic device is disposed in a Y1 direction, and the Y2 side of the drawing corresponds to a back portion of the electronic device. 
         [0017]    The operation knob  11  includes an operation surface  11 A that faces toward the front face of the electronic device body  9 . An opening  11   a  is formed at a portion of the operation surface  11 A. A communication passage  11 B continued from the opening  11   a  is formed in the operation knob  11  so as to extend in a Y2 direction. A bottom of the communication passage  11 B is parallel to a Y axis. However, the bottom of a front end of the communication passage  11 B in the Y1 direction of the drawing is formed of an inclined surface  11   b  that is inclined in a Z1 direction of the drawing toward the front end. A first light guide member  20  is provided in the communication passage  11 B of the operation knob  11 . A notch  24  to be described below faces the inclined surface  11   b.    
         [0018]    A mounting hole  9 A passing through the electronic device body  9  in the Y direction of the drawing is formed at a position facing the communication passage  11 B. A second light guide member  30  is provided in the mounting hole  9 A. 
         [0019]    As shown in  FIGS. 2 to 4 , the first light guide member  20  is triangular in plan view. The first light guide member  20  includes a light incident surface  21  at the end thereof corresponding to the Y2 side of the drawing, a light exit surface  22  at the end thereof corresponding to the Y1 side, and a reflection surface  23  at the bottom thereof corresponding to the Z2 side. 
         [0020]    The light incident surface  21  and the light exit surface  22  are formed of inclined surfaces that are inclined in directions opposite to each other, respectively. That is, as shown in  FIG. 4 , the light incident surface  21  is formed of an inclined surface that has a negative angle between a plane inclined from top left to bottom right and a first virtual plane P 1 -P 1  perpendicular to the optical axis L 1 -L 1 . Likewise, the light exit surface  22  is formed of an inclined surface that has a positive angle between a plane inclined from top right to bottom left and a second virtual plane P 2 -P 2  perpendicular to the optical axis L 1 -L 1 . For this reason, the light incident surface  21  can refract incident parallel light beams R 1  in a first direction D 1  toward the reflection surface  23 , and the light exit surface  22  can emit light beams R 4  reflected from the reflection surface  23  in a second direction D 2  toward an operator. The first virtual plane P 1 -P 1  and the second virtual plane P 2 -P 2  are parallel to a Z-X plane of the drawing. 
         [0021]    Meanwhile, the light incident surface  21  may be formed of a cylindrical surface, and, for example, may be formed of cylindrical surfaces  21   a  and  21   b  that are formed in two stages along an inclined surface as shown in  FIG. 4 . If the light incident surface  21  is formed of a cylindrical surface as described above, it is possible to suppress the spreading of light beams in a height (Z) direction while permitting the spreading of light beams in a width (X) direction. Accordingly, the vehicle-mounted electronic device can be easily seen from both a driver&#39;s seat and a passenger seat, so that the light exit surface  22  can have high brightness. 
         [0022]    As shown in cross-sectional view of  FIG. 3 , side surfaces  25  and  25  of the first light guide member  20  are formed in a tapered shape from the light incident surface  21  toward the light exit surface  22 . Therefore, an area of the light incident surface  21  is smaller than that of the light exit surface  22 . 
         [0023]    The reflection surface  23 , which is a bottom of the first light guide member  20 , is parallel to a horizontal plane (X-Y plane) except for a part thereof. The part of the reflection surface is a notch  24  that is formed by undercutting the front end of the reflection surface  23  of the first light guide member  20  corresponding to the Y1 side of the drawing. Assuming that a light exit surface is formed at a portion corresponding to the notch  24 , it is difficult for light beams to reach the front end. Therefore, it is possible to prevent or suppress the unevenness of brightness by cutting the front end. Meanwhile, an area of the reflection surface  23  is larger than that of the light exit surface  22 . 
         [0024]    A collimating part  31  is formed at an end face of the second light guide member  30 , which corresponds to the Y1 side of the drawing and is an incident side, and a light emitting surface  32  is formed at an end face of the second light guide member corresponds to the Y2 side of the drawing. 
         [0025]    The collimating part  31  includes a convex lens portion  31   a , a light receiving surface  31   b  that becomes broad from the edge of the convex lens portion  31   a  toward the outside in the shape of a megaphone, and conical surfaces  31   c . Meanwhile, the center of the collimating part  31  is disposed on the optical axis L 1 -L 1  that passes through the center of the light source  5  and is parallel to the Y axis, and the light emitting surface  32  is a surface that is perpendicular to the optical axis L 1 -L 1 . 
         [0026]    As shown in  FIG. 2 , side surfaces of the second light guide member  30  in the X1 and X2 directions are formed of cylindrical surfaces  33  and  33 . The conical surfaces  31   c  and  31   c , which are gradually tapered toward the front ends thereof in the Y2 direction, are continuously formed at the ends of the cylindrical surfaces  33  and  33  corresponding to the Y2 side of the drawing. 
         [0027]    Each of the first and second light guide members  20  and  30  is integrally made of, for example, a transparent resin material such as an acrylic resin. 
         [0028]    As shown in  FIG. 1 , while the first light guide member  20  is disposed in the communication passage  11 B, the operation knob  11  is swingably supported by the electronic device body  9 . In this case, the light exit surface  22  of the first light guide member  20  is seen through the opening  11   a  of the operation surface  11 A. Further, the operation surface  11 A of the operation knob  11  and the light exit surface  22  of the first light guide member  20  are perpendicular to the second direction D 2 . In addition, the operation knob and the first light guide member are provided so that the operation surface is flush with the light exit surface. 
         [0029]    A substrate  4  is fixed to the end of the electronic device body  9  corresponding to the Y2 side. The light source  5  is fixed to a surface of the substrate  4  corresponding to the Y1 side. Accordingly, when the substrate  4  is fixed to the end of the electronic device body  9  corresponding to the Y2 side, the light source  5  is disposed at the end of the mounting hole  9 A. Meanwhile, the light source  5  is composed of, for example, an LED or the like. 
         [0030]    As shown in  FIGS. 2 to 4 , if the first light guide member  20 , the second light guide member  30 , and the light source  5  are separated and shown, the members and the source are disposed on the optical axis L 1 -L 1  that passes through the center of the light source  5  and is parallel to the Y axis. That is, the light source  5  is provided on the Y2 side of the drawing, and the first light guide member  20  is provided on the Y1 side of the drawing. Further, the second light guide member  30  is disposed between the light source  5  and the first light guide member  20 . The collimating part  31  of the second light guide member  30  is disposed near the light source  5  so as to face the light source, and the light emitting surface  32  of the second light guide member  30  is disposed to face the light incident surface  21  of the first light guide member  20 . 
         [0031]    When the operation surface  11 A is operated by a finger F, the operation knob  11  swings and a switch mechanism (not shown) is thus switched to ON/OFF. For example, the light source  5  is set to be turned on when the switch mechanism is switched to ON, and to be turned off when the switch mechanism is switched to OFF. Accordingly, the light exit surface  22  seen on the operation surface  11 A is turned on and off. 
         [0032]    The illuminating operation of the illuminated switch having the above-mentioned structure will be described. 
         [0033]    As shown in  FIGS. 3 and 4 , light beams R 0  emitted from the light source  5  enter the second light guide member  30  through the convex lens portion  31   a , and are directed toward the light emitting surface  32  in the Y1 direction of the drawing. In this case, the light beams R 0  are converted into parallel light beams R 1  by the convex lens portion  31   a . The parallel light beams R 1  are light beams parallel to the optical axis L 1 -L 1 . 
         [0034]    Meanwhile, among the light beams R 0  emitted from the light source  5 , a part of light beams spreading in the width (X 1  and X 2 ) direction of  FIG. 3  enter from the light receiving surface  31   b  other than the convex lens portion  31   a . However, the light beams R 2  and R 2  are reflected by the conical surfaces  31   c  and  31   c , and are directed toward the light emitting surface  32  in the Y1 direction of the drawing. 
         [0035]    The parallel light beams R 1  are propagated through the second light guide member  30 , and are emitted to the first light guide member  20  through the light emitting surface  32  that is perpendicular to the optical axis L 1 -L 1 . 
         [0036]    The parallel light beams R 1  emitted from the second light guide member  30  enter the first light guide member  20  from the light incident surface  21  of the first light guide member  20 . In this case, the parallel light beams R 1  are refracted in the first direction D 1  at the light incident surface  21 . Further, an angle of refraction in this case is determined by the relationship between a ratio between a refractive index of air and a refractive index of a material of the second light guide member, and an incident angle when the parallel light beams R 1  enter the light incident surface  21 . 
         [0037]    As shown in  FIG. 4 , light beams R 3  refracted at the light incident surface  21  are propagated through the first light guide member  20 , reach the reflection surface  23  formed on the bottom of the first light guide member, and are totally reflected by the reflection surface  23 . In addition, reflected light beams R 4  are propagated through the first light guide member  20  in the second direction D 2 , and reach the light exit surface  22  provided on the Y1 side of the drawing. Since the area of the reflection surface  23  is larger than that of the light exit surface  22 , it is possible to provide a sufficient amount of light to the peripheral portion of the light exit surface  22  as compared to when the light beams R 3  are directed to the light exit surface  22  without being reflected, and to reduce the unevenness of brightness. 
         [0038]    In this case, as shown in  FIG. 4 , the second direction D 2  where the light, beams R 4  are emitted from the light exit surface  22  is perpendicular to the light exit surface  22  and the operation surface  11 A. In addition, the light exit surface  22  is set so that an eye  40  of an operator is positioned near an extension line of the second direction D 2  in a vertical direction. For this reason, the light exit surface  22  provided on the operation surface  11 A faces the operator. Therefore, an operator can easily see the light exit surface. 
         [0039]    As shown in cross-sectional view of  FIG. 3 , the side surfaces  25  and  25  of the first light guide member  20  are formed in a gradually tapered shape from the light incident surface  21  toward the light exit surface  22 . For this reason, the parallel light beams R 1  entering the first light guide member  20  enter the side surfaces  25  and  25  at an angle that is equal to or larger than a critical angle. Therefore, it is possible to focus the light beams, which enter the first light guide member  20 , on the light exit surface  22 . As a result, the light exit surface  22  of the first light guide member  20  is sufficiently illuminated. 
         [0040]    As shown in  FIG. 3 , the light beams R 2  and R 2  reflected by the conical surfaces  31   c  and  31   c  of the second light guide member  30  are totally reflected by the side surfaces  25  and  25 , and are directed to the light exit surface  22  of the first light guide member  20 . In this case, the light beams R 2  and R 2  cross each other one time, and then reach both ends of the light emitting surface  32  in the width direction (X direction). Further, when being emitted from the light exit surface  22 , the light beams R 2  and R 2  are refracted so as to be spread in the width direction (X 1  and X 2  directions). For this reason, even though an eye  40  of an operator is not positioned on an extension line of the second direction D 2 , the operator can perceive that the light exit surface  22  of the first light guide member  20  is sufficiently illuminated. Therefore, when the illuminated switch  10  is mounted on an instrument panel between a driver&#39;s seat and a passenger seat as a vehicle-mounted electronic device, it is possible to perceive that the light exit surface  22  of the first light guide member  20  seen on the operation surface  11 A of the illuminated switch  10  is sufficiently illuminated, from the driver&#39;s seat and the passenger seat that are not positioned on the extension line of the second direction D 2  in a horizontal direction. 
         [0041]    As described above, in the illuminated switch according to the embodiment of the invention, it is possible to direct the light beams, which are emitted from the light source  5 , in the second direction D 2  in a vertical direction, and to prevent the unevenness of brightness of the light exit surface  22 . In addition, since the light exit surface  22  of the first light guide member  20  from which light beams are emitted is provided to face an operator in the vertical direction, the light exit surface  22  can be sufficiently bright and easily seen from of an operator&#39;s side. 
         [0042]    In the above-mentioned embodiment, the light beams emitted from the light source  5  have been converted into parallel light beams by the collimating part  31  of the second light guide member  30 , and have then entered the light incident surface  21  of the first light guide member  20 . However, the invention is not necessarily limited thereto. That is, if the light source  5  is a laser light source capable of emitting parallel light beams, the second light guide member  30  may be not used and the light beams emitted from the light source  5  may directly enter the light incident surface  21  of the first light guide member  20 . 
         [0043]    Further, in the above-mentioned embodiment, the operation knob  11  has been swingably supported by the electronic device body  9 . However, the invention is not limited thereto, and the operation knob may be swingably mounted on a member forming a switch mechanism such as a switch case or may be mounted on the electronic device body  9  as a switch mechanism. 
         [0044]    It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims of the equivalents thereof.