Patent Publication Number: US-2023144042-A1

Title: Vehicle light guide body and vehicle lighting unit

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle light guide body and a vehicle lighting unit. 
     BACKGROUND ART 
     In recent years, for example, a configuration in which respective functions corresponding to a reflector, a shade, a projection lens, and the like are integrated into a single vehicle light guide body (see, for example, Patent Literature 1). That is, such a vehicle light guide body includes an incident part that light from a light source enters, an internal reflective part (corresponding to a reflector) that internally reflects light that has been entered, a light shielding part (corresponding to a shade) that shields a part of internally reflected light, and a light emitting part (corresponding to a projection lens) that emits light internally reflected and passing through the light shielding part to illuminate a headlight pattern in front of a vehicle. 
     CITATION LIST 
     Patent Literature 
     PTL 1: U.S. Pat. No. 6,130,602 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     The vehicle light guide body described in Patent Literature 1 is configured such that light controlled by the incident part is condensed to a focal point. For example, when fine light distribution control, for example, for low beam, is required, in a configuration in which light is controlled only by the incident part cannot finely control light distribution in some cases. 
     The present invention has been made in view of the foregoing, and it is an object of the present invention to provide a vehicle light guide body and a vehicle lighting unit that are capable of fine light distribution control. 
     Means for Solving the Problem 
     A vehicle light guide body according to the present invention includes an incident surface that light from a light source enters, a first reflective surface that internally reflects the light that has entered from the incident surface to form nearly parallel light, a second reflective surface that has a shape based on a paraboloid of revolution and internally reflects the light from the first reflective surface forward in a front-rear direction in an in-vehicle state, a third reflective surface provided in a position located in front of the second reflective surface in the front-rear direction and in a portion in at least one of end faces in a left-right direction in the in-vehicle state, a light shielding part that shields a part of the light reflected by the second reflective surface, and a light emitting surface that emits the light that has been internally reflected by the second reflective surface and has passed through the light shielding part to illuminate a headlight pattern in front of a vehicle, the second reflective surface has a diffusion pattern forming surface that reflects a part of the light from the first reflective surface toward the third reflective surface, and the third reflective surface internally reflects the light from the diffusion pattern forming surface toward the light emitting surface. 
     The third reflective surface may have a planar shape and may be formed such that a front side thereof in the front-rear direction is inclined inward in a horizontal direction. 
     The third reflective surface may have a light diffusion part that diffuses light. 
     The second reflective surface may have a light condensing pattern forming surface that internally reflects the light such that a part of the light from the first reflective surface passes through a focal point of the paraboloid of revolution and vicinity of the focal point. 
     The light condensing pattern forming surface may be disposed at center in the horizontal direction, and the diffusion pattern forming surface may be disposed in an outer side in the horizontal direction with respect to the light condensing pattern forming surface. 
     A plurality of the incident surfaces may be provided, the incident surfaces disposed in a central side in the left-right direction may be provided so as to correspond to the light condensing pattern forming surface, and the incident surfaces disposed in an outer side in the left-right direction may be provided so as to correspond to the diffusion pattern forming surface. 
     A vehicle lighting unit according to the present invention incudes a light source, and a plurality of the vehicle light guide bodies described above, each of the vehicle light guide bodies guiding and emitting light from the light source. 
     Effect of the Invention 
     According to the present invention, a vehicle light guide body and a vehicle lighting unit that are capable of fine light distribution control can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view illustrating an example of a vehicle lighting unit according to an embodiment. 
         FIG.  2    is a side view illustrating the example of the vehicle lighting unit according to the embodiment. 
         FIG.  3    is a view illustrating the example when viewed from a direction C in  FIG.  2   . 
         FIG.  4    is a view illustrating a configuration along a cross section taken along a line A-A in  FIG.  1   . 
         FIG.  5    is a view illustrating a configuration along a cross section taken along a line B-B in  FIG.  2   . 
         FIG.  6    is a view illustrating the configuration along the cross section taken along the line B-B in  FIG.  2   . 
         FIG.  7    is a diagram illustrating an example of a light condensing pattern and a diffusion pattern illuminated on a virtual screen in front of a vehicle. 
         FIG.  8    is a diagram illustrating an example of a headlight pattern illuminated on a virtual screen in front of a vehicle. 
         FIG.  9    is a view illustrating a vehicle lighting unit according to another example. 
         FIG.  10    is a view illustrating an example of a vehicle light according to the embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     An embodiment of a vehicle light guide body and a vehicle lighting unit according to the present invention will be described below with reference to the accompanying drawings. The present invention is not limited to the embodiment described below. Components in the embodiment described below include a component that can be easily replaced by a person skilled in the art or substantially a same component. In the description described below, each of front-rear, up-down, and right-left directions is a direction in an in-vehicle state where a vehicle headlight is mounted on a vehicle and indicates a direction in which a travel direction of the vehicle is viewed from a driver&#39;s seat. In this embodiment, it is assumed that the up-down direction is parallel to the vertical direction and the right-left direction is the horizontal direction. 
       FIG.  1    is a plan view illustrating an example of a vehicle lighting unit  100  according to this embodiment.  FIG.  2    is a side view illustrating the example of the vehicle lighting unit  100  according to this embodiment. 
     The vehicle lighting unit  100  illuminates a headlight pattern PF (see  FIG.  8   ) that will be described below in front of a vehicle. Using a low beam pattern as an example of the headlight pattern PF, this embodiment will be described. The vehicle lighting unit  100  has a light source  10  and a vehicle light guide body  20 . The vehicle lighting unit  100  may further include another unit having a light source, a reflector, a shade, a projection lens, or the like. In this embodiment, a configuration of the vehicle lighting unit  100  mounted on a vehicle traveling on a road for right-side travel will be described as an example. 
     [Light Source] 
     As the light source  10 , for example, a semiconductor light source is used. Such a semiconductor light source is, for example, an LED, an OLED, or the like. A luminescence surface  11  is disposed so as to face an incident surface  21  of the vehicle light guide body  20  that will be described later. The luminescence surface  11  is disposed in a state of being directed toward the vehicle light guide body  20 . In this embodiment, a plurality of light sources  10 , that is, for example, four light sources  10 , are disposed in the left-right direction. The number of the light sources  10  is not limited to four, but may be three or less, and may be five or more. 
     [Vehicle Light Guide Body] 
       FIG.  2    is a side view illustrating an example of a vehicle light guide body. The vehicle light guide body  20  guides light from the light sources  10  and emits the light forward in the in-vehicle state. The vehicle light guide body  20  according to this embodiment has, for example, a configuration in which respective functions corresponding to a reflector, a shade, a projection lens, and the like in a known projector-type vehicle headlight are integrated. As illustrated in  FIG.  1    and  FIG.  2   , the vehicle light guide body  20  includes an incident surface  21 , a first reflective surface  22 , a second reflective surface  23 , a third reflective surface  24 , a light shielding part  25 , and a light emitting surface  26 . 
     [Incident Surface] 
     A plurality of incident surfaces  21  are provided, for example, such that one light source is provided for each light source  10 . The incident surfaces  21  may be provided so as not to be in a one-to-one correspondence with the light sources  10 . For example, a plurality of incident surfaces  21  may be provided for one light source  10 . The plurality of incident surfaces  21  are disposed side by side in the left-right direction in the in-vehicle state. Each of the incident surfaces  21  is formed, for example, in a truncated conical shape. In this embodiment, for example, four incident surfaces  21  are arranged. A diameter r 2  of each of the incident surfaces  21  disposed in an outer side in the left-right direction is smaller than a diameter r 1  of each of the incident surfaces  21  disposed in a central side in the left-right direction. In this embodiment, the diameter r 2  of each of the two incident surfaces  21  disposed in the outer side in the left-right direction is smaller than the diameter r 1  of each of the two incident surfaces  21  disposed in the central side in the left-right direction. A ratio between the diameter r 1  and the diameter r 2 , that is, a ratio r 1 /r 2 , can be, for example, 0.5 or more and less than 1. Hereinafter, occasionally, the two incident surfaces  21  in the central side in the left-right direction are each written as a central incident surface  21 M, the two incident surfaces in the outer side in the left-right direction are each written as an outer incident surface  21 N, and both are distinguished from each other. 
     Each incident surface  21  has a first surface  21   a  and a second surface  21   b.  Light from each light source  10  enters the first surface  21   a  and the second surface  21   b.  The first surface  21   a  faces the luminescence surface  11 . The first surface  21   a  is a flat surface or a convex surface protruding toward the light source  10 . The second surface  21   b  is disposed in a lateral side of the light source  10  and is disposed in a cylindrical surface shape so as to surround the luminescence surface  11  and the first surface  21   a  of the light source  10 . 
     [First Reflective Surface] 
     Each first reflective surface  22  internally reflects light that has entered from the incident surface  21  to form substantially parallel light. The first reflective surface  22  is disposed so as to surround the second surface  21   b  of the incident surface  21 , and reflects light that has entered from the second surface  21   b  toward the second reflective surface  23 . In this embodiment, the first reflective surfaces  22  are provided so as to correspond to the incident surfaces  21 . 
       FIG.  3    illustrates the configuration when viewed from a direction of an arrow C in  FIG.  2   . As illustrated in  FIG.  3   , the two first reflective surfaces  22  disposed in the central side in the left-right direction partially overlap each other. Specifically, the two first reflective surfaces  22  are disposed so as to be connected in a straight line in a central portion  22 J. 
     [Second Reflective Surface] 
       FIG.  4    is a view illustrating a configuration along a cross section taken along a line A-A in  FIG.  1   . As illustrated in  FIG.  4   , the second reflective surface  23  has a shape based on a paraboloid of revolution PR. The second reflective surface  23  has a focal point P. The focal point P is disposed in a position in vicinity of a focal point of the light emitting surface  26  that will be described later. The second reflective surface  23  reflects light from the first reflective surface  22  toward the focal point P, that is, in front of the vehicle. The second reflective surface  23  has an axis AX 2  that is in parallel to an optical axis AX 1  of light that is reflected by the first reflective surface  22  and internally reflects light toward the focal point P of the paraboloid of revolution PR. 
       FIG.  5    is a view illustrating a configuration along a cross section taken along a line B-B in  FIG.  2   . As illustrated in  FIG.  5   , in this embodiment, a plurality of second reflective surfaces  23  are disposed side by side in the left-right direction in an in-vehicle state. The plurality of second reflective surfaces  23  include a light condensing pattern forming surface  23 M and a diffusion pattern forming surface  23 N. 
     As illustrated in  FIG.  5   , the light condensing pattern forming surface  23 M internally reflects the light so that the light passes through the focal point P and the vicinity of the focal point P. Of the plurality of second reflective surfaces  23 , the second reflective surface  23  disposed in a vertical direction with respect to the optical axis AX 1  of the light source  10  in the in-vehicle state is the light condensing pattern forming surface  23 M. The light condensing pattern forming surface  23 M is disposed at center in the left-right direction. The light condensing pattern forming surface  23 M is disposed so as to correspond to the two central incident surfaces  21 M. The light condensing pattern forming surface  23 M reflects light that has entered the two central incident surfaces  21 M and has been reflected by the first reflective surface  22 . 
     The diffusion pattern forming surface  23 N reflects a part of light from the first reflective surface  22  toward the third reflective surface  24  that will be described later. Therefore, the diffusion pattern forming surface  23 N has, for example, a shape in which an end portion thereof located closer to the light condensing pattern forming surface  23 M in the left-right direction is deformed forward with respect to a shape based on the paraboloid of revolution PR. One diffusion pattern forming surface  23 N is disposed in each of outer sides of the light condensing pattern forming surface  23 M in the left-right direction. The diffusion pattern forming surface  23 N is disposed so as to correspond to each outer incident surface  21 N. The diffusion pattern forming surface  23 N reflects light that has entered each outer incident surface  21 N and has been reflected by the first reflective surface  22 . A path of light on the diffusion pattern forming surface  23 N will be described later. 
     [Third Reflective Surface] 
     The third reflective surface  24  is provided in a position located in front of the second reflective surface  23  and in a portion in each of end faces on both sides in the left-right directions. The third reflective surface  24  internally reflects light reflected by the diffusion pattern forming surface  23 N. The third reflective surface  24  internally reflects light from the diffusion pattern forming surface  23 N toward the light emitting surface  26 . For example, the third reflective surface  24  has a planar shape and is formed such that a front side thereof is inclined inward in the horizontal direction. The third reflective surface  24  is disposed in a position where the reflective surface  24  is connected to both ends of a light shielding part  25  that will be described later in the left-right direction. The third reflective surface  24  has a light diffusion part  24   a  that diffuses light. The light diffusion part  24   a  diffuses light reflected by the third reflective surface  24  in the horizontal direction. 
       FIG.  6    is a view illustrating the configuration along the cross section taken along the line B-B in  FIG.  2   . As illustrated in  FIG.  6   , the diffusion pattern forming surface  23 N reflects a part of light from the first reflective surface  22  toward the third reflective surface  24 . Light reflected by the diffusion pattern forming surface  23 N reaches the third reflective surface  24 . The third reflective surface  24  internally reflects the light toward the light emitting surface  26 . Thus, reflection of all light inside the vehicle light guide body  20  on the light emitting surface  26  can be suppressed. 
     [Light Shielding Part] 
     The light shielding part  25  shields a part of light internally reflected by the second reflective surface  23  and the third reflective surface  24 . For example, as illustrated in  FIG.  2   , the light shielding part  25  has a bent shape such that surfaces  20   e  and  20   f  of the vehicle light guide body  20  disposed in a lower position in the in-vehicle state form a corner  20   g.  The surface  20   e  is formed along a horizontal plane. The surface  20   f  is formed so as to be, for example, inclined downward in a forward direction. The corner  20   g  has a recessed shape when the vehicle light guide body  20  is viewed from outside (from bottom) and protrudes toward an inside of the vehicle light guide body  20 . The corner  20   g  linearly extends in the left-right direction. The light shielding part  25  forms, for example, a cutoff line Pc of the headlight pattern that will be described later at the corner  20   g.  The cutoff line Pc includes a horizontal cutoff line and a diagonal cutoff line. In this case, the corner  20   g  has a horizontal portion (not illustrated) to form the horizontal cutoff line and an inclined portion (not illustrated) to form the diagonal cutoff line. 
     The light shielding part  25  is provided in an area including the corner  20   g.  For example, the light shielding part  25  may shield light by refracting or internally reflecting light that reaches the light shielding part  25  in a direction different from a direction of the light emitting surface  26  and may shield light by disposing a light absorbing layer in a portion of the surface  20   e  including the corner  20   g  corresponding to the light shielding part  25  in advance to cause the light absorbing layer to absorb light. The light internally reflected or refracted by the light shielding part  25  is emitted to outside of the vehicle light guide body  20  and is absorbed by an inner housing or the like disposed outside the vehicle light guide body  20 . 
     [Light Emitting Surface] 
     The light emitting surface  26  emits light that has been internally reflected by the second reflective surface  23  and has passed through the light shielding part  25  to illuminate the headlight pattern PF (see  FIG.  8   ) in front of the vehicle. The light emitting surface  26  has, for example, a curved shape. The light emitting surface  26  has an unillustrated focal point and an optical axis. The focal point of the light emitting surface  26  is disposed in a position in the vicinity of the focal point P of the second reflective surface  23 . 
     A prism  20   h  is formed on an upper surface  20   d  of the vehicle light guide body  20 . The prism  20   h  diffuses the light internally reflected by the second reflective surface  23 . Thus, the light emitted from the upper surface to the outside of the vehicle light guide body  20  can be prevented from becoming glare. 
     [Operation] 
     Next, an operation of the vehicle lighting unit  100  configured in a manner described above will be described.  FIG.  7    is a diagram illustrating an example of a light condensing pattern and a diffusion pattern illuminated on a virtual screen in front of a vehicle.  FIG.  8    is a diagram illustrating an example of a headlight pattern illuminated on a virtual screen in front of a vehicle. Each of  FIG.  7    and  FIG.  8    illustrates a pattern corresponding to a vehicle travelling on a left side of a road. For a vehicle travelling on a right side of a road, a pattern obtained by laterally reversing the pattern illustrated in each of  FIG.  7    and  FIG.  8    may be illuminated. In each of  FIG.  7    and  FIG.  8   , a line V-V indicates a vertical line of the screen and a line H-H indicates a horizontal line of the screen laterally extending. Herein, an intersection of the vertical line and the horizontal line is assumed to be a reference position in the horizontal direction. 
     By turning on each of the light sources  10  in the vehicle lighting unit  100 , light is emitted from the luminescence surface  11 . Of the light, light that has entered the first surface  21   a  of the incident surface  21  is formed into nearly parallel light by the first surface  21   a.  Light that has entered the second surface  21   b  of the incident surface  21  is internally reflected by the first reflective surface  22  and becomes nearly parallel light. The light formed in a manner described above is internally reflected toward the light emitting surface  26  on the second reflective surface  23 . 
     For example, light L 1  that has entered from the central incident surface  21 M, has been internally reflected by the first reflective surface  22 , and has become nearly parallel light is, as illustrated in  FIG.  5   , internally reflected by the light condensing pattern forming surface  23 M, passes through the focal point P and the vicinity of the focal point P in the light shielding part  25 , and is emitted from the light emitting surface  26 . The light L 1  forms a light condensing pattern P 1  in front of the vehicle, as illustrated in  FIG.  7   . 
     Each of light L 2  and light L 3  that has entered from the outer incident surface  21 N, has been internally reflected by the first reflective surface  22 , and has become nearly parallel light is internally reflected internally reflected by the diffusion pattern forming surface  23 N in the cross section taken along the line B-B in  FIG.  2   , that is, a cross section (transverse plane) parallel to the horizontal plane, as illustrated in  FIG.  6   . The light L 2  internally reflected by the diffusion pattern forming surface  23 N passes through the focal point P and a position that is shifted horizontally outward from the focal point P in the in-vehicle state in the light shielding part  25  and is emitted from the light emitting surface  26 . The light L 2  forms a diffusion pattern P 2  in front of the vehicle, as illustrated in  FIG.  7   . The light L 3  internally reflected by the diffusion pattern forming surface  23 N reaches the third reflective surface  24  on a side closer to the light emitting surface  26  than the light shielding part  25  and is internally reflected by the third reflective surface  24 . When the light L 3  is internally reflected by the third reflective surface  24 , the light L 3  is diffused horizontally by the light diffusion part  24   a  provided on the third reflective surface  24 . The light L 3  internally reflected by the third reflective surface  24  reaches the light emitting surface  26 . The light L 3  that has reached the light emitting surface  26  is emitted from the light emitting surface  26  to the front of the vehicle. The light L 3  forms a diffusion pattern P 3  in front of the vehicle, as illustrated in  FIG.  7   . The diffusion patterns P 2  and P 3  are formed so as to spread out in the left-right direction, as compared to the light condensing pattern P 1 . The light L 3  is diffused by the light diffusion part  24   a  of the third reflective surface  24 , and therefore, an outline of the diffusion pattern P 3  is prevented from becoming clear. Therefore, the diffusion pattern P 3  can be formed so as to be blended in with surroundings thereof. In  FIG.  6   , an example is illustrated using the light L 2  and the light L 3  internally reflected by the diffusion pattern forming surface  23 N in an upper side of  FIG.  6   , but the light internally reflected by the diffusion pattern forming surface  23 N in a lower side of  FIG.  6    is also included in the light L 2  and the light L 3  in a similar manner. That is, the light L 2  and the light L 3  include light internally reflected by the diffusion pattern forming surfaces  23 N in both the upper and lower sides of  FIG.  6   . 
     Therefore, when each light source  10  of the vehicle lighting unit  100  is turned on, as illustrated in  FIG.  8   , the headlight pattern PF in which the light condensing pattern P 1  and the diffusion patterns P 2  and P 3  are superimposed is formed in front of the vehicle. Thus, the headlight pattern PF with a luminous intensity properly adjusted on inner and outer sides in the left-right direction is formed in front of the vehicle. 
     In the description above, the configuration in which the light sources  10  each of which causes light to enter a corresponding one of the two central incident surfaces  21 M and the two outer incident surfaces  21 N are disposed is employed, but the present invention is not limited thereto. For example, a configuration in which only the light sources  10  that cause light to enter the two central incident surfaces  21 M are disposed and the light sources  10  that cause light to enter the two outer incident surfaces  21 N are not disposed may be employed. In this case, light from the light sources  10  enters only the two central incident surfaces  21 M, so that only the light condensing pattern P 1  is formed by the vehicle light guide body  20 . A configuration in which only the light sources  10  that cause light to enter the two outer incident surfaces  21 N are disposed and the light sources  10  that cause light to enter the two central incident surfaces  21 M are not disposed may be employed. In this case, light from the light sources  10  enters only the two outer incident surfaces  21 N, so that only diffusion patterns P 2  and P 3  are formed by the vehicle light guide body  20 . With this combination, the lens members can be made common for a plurality of light distribution patterns by disposing units that fulfill a function as a headlight as appropriate, and therefore, costs can be reduced. 
       FIG.  9    is a view illustrating a vehicle lighting unit  100 A according to another example. As illustrated in  FIG.  9   , the vehicle lighting unit  100 A includes the light sources  10  and a vehicle light guide body  20 A. The vehicle light guide body  20 A includes outer incident surfaces  21 N disposed in left and right outer sides in the left-right direction, a first reflective surface  22 A, a second reflective surface  23 A, and a third reflective surface  24 A that correspond to each of the outer incident surfaces  21 N. The second reflective surface  23 A is the diffusion pattern forming surface  23 N. In contrast to the configuration of the vehicle light guide body  20  illustrated in  FIG.  1    or the like, the vehicle light guide body  20 A has a configuration in which the central incident surface  21 M disposed in the central side of the vehicle in the left-right direction and the first reflective surface  22  and the second reflective surface  23  (light condensing pattern forming surface  23 M) corresponding to the central incident surface  21 M are not provided. Therefore, light that enters the vehicle light guide body  20 A from the light sources  10  forms the diffusion patterns P 2  and P 3  in front of the vehicle. As described above, the vehicle light guide body  20 A is a diffusion light guide body in which all the second reflective surfaces  23 A serve as the diffusion pattern forming surfaces  23 N and form the diffusion patterns P 2  and P 3  in front of the vehicle. Other configurations of the vehicle light guide body (diffusion light guide body)  20 A are similar to those of the vehicle light guide body  20  described above. 
       FIG.  10    is a view illustrating an example of a vehicle light  200  according to the present invention.  FIG.  10    illustrates the example when viewed from a front side in the in-vehicle state. The vehicle light  200  illustrated in  FIG.  10    includes a housing  201 , an outer lens  202 , a light source  210 , and a plurality of vehicle light guide bodies  220 . The vehicle light  200  has a configuration in which, for example, two vehicle light guide bodies  220  are disposed in a light chamber surrounded by the housing  201  and the outer lens  202  herein. The number of the vehicle light guide bodies  220  to be disposed in the lamp chamber may be one or three or more. An arrangement of the vehicle light guide bodies  220  is not limited to an arrangement in which the vehicle light guide bodies  220  are disposed side by side in the left-right direction as viewed from the front, may be an arrangement in which the vehicle light guide bodies  220  are disposed in the up-down direction, may be an arrangement in which the vehicle light guide bodies  220  are disposed in an oblique direction, and may be an arrangement in which the vehicle light guide bodies  220  are disposed in directions of combination of two or more of the left-right direction, the up-down direction, and the oblique direction. Each of the vehicle light guide bodies  220  can be configured such that, of the vehicle light guide bodies  20  and  20 A described above, vehicle light guide bodies of the same type or different types are combined and thus disposed. In addition, at least one of the vehicle light guide bodies  220  may be the vehicle light guide body  20  or  20 A and the other ones thereof may be vehicle light guide bodies each having some other configuration. 
     As described above, the vehicle light guide body  20  according to this embodiment includes the incident surface  21  that light from the light source  10  enters, the first reflective surface  22  that internally reflects light that has entered from the incident surface  21  to form nearly parallel light, the second reflective surface  23  that has a shape based on a paraboloid of revolution PR and internally reflects the light from the first reflective surface  22  forward in the front-rear direction in the in-vehicle state, the third reflective surface  24  provided in a position located in front of the second reflective surface  23  in the front-rear direction and in a portion in at least one of end faces in the left-right direction in the in-vehicle state, the light shielding part  25  that shields a part of the light reflected by the second reflective surface  23 , and the light emitting surface  26  that emits the light that has been internally reflected by the second reflective surface  23  and has passed through the light shielding part  25  to illuminate the headlight pattern in front of the vehicle, the second reflective surface  23  has the diffusion pattern forming surface  23 N that reflects a part of the light from the first reflective surface  22  toward the third reflective surface  24 , and the third reflective surface  24  internally reflects the light from the diffusion pattern forming surface  23 N toward the light emitting surface  26 . 
     According to this configuration, light distribution can be controlled on the second reflective surface  23 , and therefore, fine control of light distribution than that, for example, in a configuration in which light distribution is controlled only at an incident part. Thus, appropriate light distribution control can be performed even when fine light distribution control, for example, for low beam, is required. Moreover, the third reflective surface  24  internally reflects light from the diffusion pattern forming surface  23 N such that the light reaches the light emitting surface  26  by a total reflection angle or more with respect to the light emitting surface  26 , so that it is possible to prevent all light from being reflected inside the vehicle light guide body  20  on the light emitting surface  26 . Therefore, light from the light sources can be contributed to pattern illumination without waste. 
     In the vehicle light guide body  20  according to this embodiment, the third reflective surface  24  may have a planar shape and may be formed such that the front side thereof in the front-rear direction is inclined inward in the horizontal direction. Thus, light can be caused to reach the light emitting surface  26  by an angle with respect to the emitting surface  26 . 
     In the vehicle light guide body  20  according to this embodiment, the third reflective surface  24  may have a light diffusion part  24   a  that diffuses light. Thus, the outline of the diffusion pattern P 3  is prevented from becoming clear and the diffusion pattern P 3  can be formed so as to be blended in with surroundings thereof. 
     In the vehicle light guide body  20  according to this embodiment, the second reflective surface  23  may have the light condensing pattern forming surface  23 M that internally reflects light from the first reflective surface  22  such that a part of the light passes through a focal point of the paraboloid of revolution PR and vicinity of the focal point. By providing the light condensing pattern forming surface  23 M and the diffusion pattern forming surface  23 N in one vehicle light guide body  20 , one or both of the light condensing pattern P 1  and the diffusion patterns P 2  and P 3  can be formed by one vehicle light guide body  20 . 
     In the vehicle light guide body  20  according to this embodiment, the light condensing pattern forming surface may be disposed in center in the horizontal direction and the diffusion pattern forming surface  23 N may be disposed in an outer side in the horizontal direction with respect to the light condensing pattern forming surface. By disposing the light condensing pattern forming surface  23 M in the central side in the left-right direction, it is easier to condense light at the focal point P and in the vicinity of the focal point P than, for example, when the light condensing pattern forming surface  23 M is disposed in the outer side in the left-right direction, and therefore, the light condensing pattern P 1  can be easily formed. By disposing the diffusion pattern forming surface  23 N in the outer side in the left-right direction, it is easier to diffuse light in the left-right direction than, for example, when the diffusion pattern forming surface  23 N is disposed in the central side in the left-right direction, and therefore, the diffusion patterns P 2  and P 3  can be easily formed. 
     In the vehicle light guide body  20  according to this embodiment, a plurality of incident surfaces  21  may be provided, the incident surfaces  21  disposed in the central side in the left-right direction may be provided so as to correspond to the light condensing pattern forming surface  23 M, and the incident surfaces  21  disposed in the outer side in the left-right direction may be provided so as to correspond to the diffusion pattern forming surface  23 N. Thus, light that has entered from the incident surfaces  21  can be precisely controlled. 
     The vehicle lighting unit  200  according to this embodiment includes the light source  210  and the plurality of above-described vehicle light guide bodies  220  that guide and emit light from the light source  210 . According to this configuration, the vehicle lighting unit  200  as a whole can obtain a headlight pattern formed by combining illumination patterns of the plurality of vehicle light guide bodies  220 . 
     The technical scope of the present invention is not limited to the above-described embodiment, and changes can be made as appropriate without departing from the gist of the present invention. In the above-described embodiment, the configuration of the vehicle lighting unit  100  that is mounted on a vehicle traveling on a road for right-side travel has been described as an example, but the present invention is not limited thereto and similar applies to a case where a vehicle headlight is mounted on a vehicle traveling on a road for left-side travel. 
     In the above-described embodiment, the description has been made using the low beam pattern as an example of the headlight pattern PF, but the present invention is not limited thereto and may be any other pattern, for example, a high beam pattern or the like. In the vehicle lighting unit  200  provided with the plurality of vehicle light guide bodies  220  therein, the vehicle light guide bodies  220  that form patterns of different types may be provided. 
     DESCRIPTION OF REFERENCE NUMERALS 
     AX 1  Optical axis 
     AX 2  Axis 
     L 1 , L 2 , L 3  Light 
     P Focal point 
     P 1  Light condensing pattern 
     P 2 , P 3  Diffusion pattern 
     Pc Cutoff line 
     PF Headlight pattern 
     PR Paraboloid of revolution 
     r 1 , r 2  Diameter 
       10 ,  210  Light source 
       11  Luminescence surface 
       20 ,  20 A,  220  Vehicle light guide body 
       20   d  Upper surface 
       20   e,    20   f  Surface 
       20   g  Corner 
       20   h  Prism 
       21  Incident surface 
       21 M Central incident surface 
       21 N Outer incident surface 
       21   a  First surface 
       21   b  Second surface 
       22 ,  22 A First reflective surface 
       22 J Central portion 
       23 ,  23 A Second reflective surface 
       23 M Light condensing pattern forming surface 
       23 N Diffusion pattern forming surface 
       24 ,  24 A Third reflective surface 
       24   a  Light diffusion part 
       25  Light shielding part 
       26  Light emitting surface 
       100 ,  100 A Vehicle lighting unit 
       200  Vehicle light 
       201  Housing 
       202  Outer lens