Patent Publication Number: US-11662075-B2

Title: Lamp for vehicle and vehicle including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority from and the benefit of Korean Patent Application No. 10-2021-0111718, filed on Aug. 24, 2021, which is hereby incorporated by reference for all purposes as if set forth herein. 
     TECHNICAL FIELD 
     Exemplary embodiments relate to a lamp for a vehicle and a vehicle including the lamp and, more particularly, to a lamp for a vehicle, which minimizes an optical loss to enhance an optical efficiency, and a vehicle including the lamp. 
     BACKGROUND 
     In general, a vehicle is provided with various types of lamps having: a lighting function for easily identifying an object located around the vehicle during night driving; and a signal function for informing other vehicles or road users of the driving state of the vehicle. For example, a low beam lamp, a high beam lamp, a daytime running light (DRL) lamp, and the like are mounted to the front of the vehicle. Among these lamps, the low beam lamp forms a light distribution pattern that has a cut-off line shape in an upper portion thereof. 
     Meanwhile, in order for the low beam lamp to form the cut-off line as described above, a shield is disposed at a position, where a focus of an exit-side lens is formed, thereby forming the cut-off line. Here, the light is diffused at the position where the focus of the exit-side lens is formed. 
       FIG.  1    illustrates a lamp for a vehicle according to the related art, which uses an optical system according to the related art to form a low beam pattern. 
     Referring to  FIG.  1   , a lamp  1  for a vehicle according to the related art includes: a light source unit  10  including a light source  11  and a collimator  12  by which light emitted from the light source  11  is made to be parallel light; and a lens structure  20  that projects the light emitted from the light source unit  10  to form a certain beam pattern. The lens structure  20  includes: a body part  21 ; an entrance part  22  which is formed on a surface of the body part  21 , to which the light is incident, and allows the light emitted from the light source unit  10  to be incident to the body part  21 ; and an exit part  23  which is formed on a surface of the body part  21 , from which the light is emitted, and allows the light incident from the body part  21  to be emitted forward. The body part  21  includes a recessed portion  24  which is recessed toward a central region, in the up-down direction, of the body part  21 . Here, the recessed portion  24  may serve as a shield that blocks the light, which is emitted from the light source unit  10  and arrives at the recessed portion  24 , and forms a cut-off line. 
     However, in the lamp  1  for a vehicle that uses an optical system according to the related art, the light incident via a lower portion of the entrance part  22  arrives at the recessed portion  24  and is then totally reflected therefrom as illustrated in  FIG.  1   . Thus, an optical path changes, and the light is emitted to a non-light distribution region, resulting in an optical loss. 
     SUMMARY 
     Exemplary embodiments of the present invention provide a lamp for a vehicle, in which a curvature, in the vertical direction, of a lower region of an entrance part is greater than a curvature, in the vertical direction, of an upper region thereof. Therefore, the lamp may minimize an optical loss and enhance an optical efficiency. 
     A first exemplary embodiment of the present invention provides a lamp for a vehicle, the lamp including: a light source unit configured to emit light; and a lens structure which is located in front of the light source unit and projects the light emitted from the light source unit to form a certain beam pattern, wherein the lens structure includes: a body part; an entrance part which is formed on a surface of the body part, to which the light is incident, and allows the light emitted from the light source unit to be incident to the body part; and an exit part which is formed on a surface of the body part, from which the light is emitted, and allows the light incident to the body part to be emitted forward, wherein the body part includes a recessed portion which is recessed toward a central region, in the up-down direction, of the body part, and the recessed portion is configured to block the light which is emitted from the light source unit and arrives at the recessed portion, wherein the entrance part includes an upper region and a lower region which are provided in an upper portion and a lower portion, respectively, with respect to an optical axis of the exit part, and curvature of the upper region is different from curvature of the lower region. 
     The curvature of the lower region may be greater than the curvature of the upper region. 
     The curvature of the lower region in the vertical direction may be greater than the curvature of the upper region in the vertical direction. 
     The lower region may be configured such that the light emitted from the light source unit is collected in the vicinity of a focus formed by the exit part. 
     The entrance part and the exit part may be provided as an anamorphic lens. 
     A focus of the lower region in the vertical direction may correspond to a focus of the exit part in the vertical direction. 
     A focal length of the exit part may be less than a focal length of the lower region. 
     A focal length of the exit part may be equal to a focal length of the lower region. 
     The light source unit may include: a light source configured to generate the light; and a collimator which is provided in a direction from the light source toward the lens structure, and allows the light emitted from the light source to be converted into parallel light, which is parallel to an optical axis of the lens structure, and then incident to the lens structure. 
     The light source, the collimator, and the lens structure may be arranged in the optical axis of the lens structure. 
     The body part, the entrance part, and the exit part may be integrally formed. 
     The recessed portion may have a shape that is recessed from a lower surface of the body part toward the central region. 
     The recessed portion may include: a blocking layer configured to block a portion of the light incident to the body part; and a cut-off edge formed at an upper end of the blocking layer and configured to form a cut-off line of a low beam pattern. 
     The cut-off edge may be provided at a position corresponding to a focus, in the vertical direction, of the exit part. 
     A size of the entrance part in the up-down direction may be greater than a size of the exit part in the up-down direction or equal to the size of the exit part in the up-down direction. 
     A second exemplary embodiment of the present invention provides a vehicle including a lamp for a vehicle, wherein the lamp includes: a light source unit configured to emit light; and a lens structure which is located in front of the light source unit and projects the light emitted from the light source unit to form a certain beam pattern, wherein the lens structure includes: a body part; an entrance part which is formed on a surface of the body part, to which the light is incident, and allows the light emitted from the light source unit to be incident to the body part; and an exit part which is formed on a surface of the body part, from which the light is emitted, and allows the light incident to the body part to be emitted forward, wherein the body part includes a recessed portion which is recessed toward a central region, in the up-down direction, of the body part, and the recessed portion is configured to block the light which is emitted from the light source unit and arrives at the recessed portion, wherein the entrance part includes an upper region and a lower region which are provided in an upper portion and a lower portion, respectively, with respect to an optical axis of the exit part, and curvature of the upper region is different from curvature of the lower region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention. 
         FIG.  1    is a view when a lamp for a vehicle according to the related art is viewed from the side to explain a path of light generated in a light source. 
         FIG.  2    is a side view of a lamp for a vehicle according to an exemplary embodiment of the present disclosure to explain a path of light generated in a light source. 
         FIG.  3    is a side view of a lamp for a vehicle according to an exemplary embodiment of the present disclosure to explain a path of light according to focal lengths of an exit part and a lower region of an entrance part. 
         FIG.  4    is a perspective view of a lamp for a vehicle according to the present disclosure to explain a shape of a recessed portion. 
         FIG.  5    is a view illustrating a state in which horizontal off-axis light passes through the inside of a lens structure according to an exemplary embodiment of the present disclosure. 
         FIG.  6    is an enlarged view illustrating a recessed portion of a lens structure according to an exemplary embodiment of the present disclosure. 
         FIG.  7    is a table for comparing the total light amounts and maximum luminous intensities of light distribution patterns formed by a lamp for a vehicle according to the related art and a lamp for a vehicle according to an exemplary embodiment of the present disclosure. 
         FIG.  8    is a view for comparing the shapes of low beam light distribution patterns formed by a lamp for a vehicle according to the related art and a lamp for a vehicle according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail according to the accompanying drawings. 
     First, exemplary embodiments described below are suitable for understanding the technical characteristics of a lamp for a vehicle according to the present disclosure. However, the present disclosure is not limited to the exemplary embodiments described below, or the technical features of the present disclosure are not limited by the described exemplary embodiments, and various modifications are possible within the technical scope of the present disclosure. 
       FIG.  1    is a view when a lamp for a vehicle according to the related art is viewed from the side to explain a path of light generated in a light source.  FIG.  2    is a side view of a lamp for a vehicle according to an exemplary embodiment of the present disclosure to explain a path of light generated in a light source.  FIG.  3    is a side view of a lamp for a vehicle according to an exemplary embodiment of the present disclosure to explain a path of light according to focal lengths of an exit part and a lower region of an entrance part.  FIG.  4    is a perspective view of a lamp for a vehicle according to the present disclosure to explain a shape of a recessed portion.  FIG.  5    is a view illustrating a state in which horizontal off-axis light passes through the inside of a lens structure according to an exemplary embodiment of the present disclosure.  FIG.  6    is an enlarged view illustrating a recessed portion of a lens structure according to an exemplary embodiment of the present disclosure. Also,  FIG.  7    is a table for comparing the total light amounts and maximum luminous intensities of light distribution patterns formed by a lamp for a vehicle according to the related art and a lamp for a vehicle according to an exemplary embodiment of the present disclosure.  FIG.  8    is a view for comparing the shapes of low beam light distribution patterns formed by a lamp for a vehicle according to the related art and a lamp for a vehicle according to an exemplary embodiment of the present disclosure. 
     A lamp  2  for a vehicle according to an exemplary embodiment of the present disclosure includes a light source unit  100  and a lens structure  200 . 
     Herein, the light source unit  100  is configured to generate and emit light. Here, the light source unit  100  may use various elements and devices capable of emitting light. The light source unit  100  may include a light source  110  that generates light, and the light source  110  may be, for example, a light emitting diode (hereinafter, referred to as an LED). However, the light source  110  is not limited to the LED. 
     For example, the light source unit  100  may emit parallel light forward toward the lens structure  200 . Specifically, the light source unit  100  may further include a collimator  120 . The collimator  120  is provided in a direction from the light source  110  toward the lens structure  200 , and may allow the light emitted from the light source  110  to be converted into parallel light, which is parallel to an optical axis AX of the lens structure  200 , and then incident to the lens structure  200 . Also, the light source  110 , the collimator  120 , and the lens structure  200  may be arranged in the optical axis AX of the lens structure  200  and, more specifically, in the optical axis AX of an exit part  230 . 
     Meanwhile, the lens structure  200  is located in front of the light source unit  100  and projects the light emitted from the light source unit  100  to form a certain beam pattern. Hereinafter, for convenience of description, a direction in which the light is emitted, that is, a direction from the light source  110  toward the lens structure  200  is referred to as the front direction. The opposite direction from the front direction is referred to as the rear direction. 
     More specifically, the lens structure  200  includes a body part  210 , an entrance part  220 , and an exit part  230  as illustrated in  FIG.  2   . 
     Here, the body part  210  constitutes a body of the lens structure  200  and may be made of a material through which the incident light passes. 
     Specifically, the body part  210  may include: an upper surface  211  for connecting the entrance part  220  to the exit part  230 ; a lower surface  212  facing the upper surface  211 ; and a side surface  213  located between the upper surface  211  and the lower surface  212 . 
     Here, the upper surface  211 , the lower surface  212 , and the side surface  213  of the body part  210  may have various shapes depending on sizes and the like of the entrance part  220  and the exit part  230  which will be described later. For example, the upper surface  211  may be inclined downward in the forward direction. Also, the lower surface  212  may be formed horizontally or inclined downward in the forward direction but less inclined than the upper surface  211 , or may be inclined upward in the forward direction. 
     Meanwhile, the body part  210  may include a recessed portion  240  which is recessed toward a central region, in the up-down direction, of the body part  210 . Here, the recessed portion  240  may be provided to block the light which is emitted from the light source unit  100  and arrives at the recessed portion  240 . 
     Specifically, the recessed portion  240  may have a shape that is recessed from the lower surface  212  of the body part  210  toward the central region. Here, the recessed portion  240  may be located on a path through which the light incident to the body part  210  travels. Also, the recessed portion  240  may be provided to block a portion of the light. 
     Specifically, according to the lamp  2  for a vehicle according to an exemplary embodiment of the present disclosure, a focus of the exit part  230  may be positioned inside the body part  210  of the lens structure  200 , and the recessed portion  240  may be formed at the central region of the body part  210 , and a portion of the light may be blocked at a position corresponding to the focus of the exit part  230 . 
     More specifically, a portion of the light is blocked by the recessed portion  240  according to the present disclosure, and thus the light emitted from the exit part  230  may form a cut-off line of a low beam pattern. That is, according to the present disclosure, the recessed portion  240  is formed by modifying the shape of the body part  210  to form the cut-off line of the low beam pattern. Thus, the cut-off line may be formed without a separate shield member. Here, the detailed shape of the recessed portion  240  will be described later. 
     Meanwhile, the entrance part  220  is formed on a surface of the body part  210 , to which the light is incident, and allows the light emitted from the light source unit  100  to be incident to the body part  210 . That is, the entrance part  220  may be formed on the surface that faces the rear of the body part  210 , and may be configured such that the light emitted from the light source unit  100  is collected inside the body part  210 . 
     Also, the entrance part  220  may be formed as various lenses. For example, the entrance part  220  may be formed as a convex lens, an aspherical surface lens, or an anamorphic lens that is recessed toward the light source unit  100 . 
     Also, the entrance part  220  may have various sizes. Specifically, the exit part  230 , which will be described later, is a part exposed to the outside, and thus the size thereof is limited by exterior design or regulations for a lamp. However, the entrance part  220  is located inside a vehicle body and not exposed to the outside, and thus the size limitation is relatively small. Thus, the size of the entrance part  220  may be equal to that of the exit part  230  or relatively greater than that of the exit part  230 . For example, the size of the entrance part  220  in the up-down direction may be greater than the size of the exit part  230  in the up-down direction, or may be equal to the size of the exit part  230  in the up-down direction. Accordingly, the light emitted from the light source unit  100  may be collected as much as possible in the entrance part  220 , and thus optical loss may be minimized. 
     Meanwhile, in the lamp for a vehicle according to the related art, a portion of the light incident from the entrance part  22  may be blocked by the recessed portion  24  as described above. Specifically, as illustrated in  FIG.  1   , among light incident to the entrance part  22 , light, which is incident to a lower region of the entrance part  22  with respect to the optical axis AX of the exit part  23 , is totally reflected by the recessed portion  24 . Thus, this light does not contribute to forming a beam pattern because an optical path thereof is changed. Accordingly, optical loss may occur, and optical performance of the lamp for a vehicle may deteriorate. 
     In order to solve the above limitation, the present disclosure provides the lamp for a vehicle, in which the entrance part  220  is divided into an upper region  221  and a lower region  222  with respect to an optical axis AX of the exit part  230 . The light incident through the lower region  222  is collected in the vicinity of the focus of the exit part  230 , and thus optical loss may be minimized. 
     Specifically, the entrance part  220  according to the present disclosure may include, as illustrate in  FIG.  2   , an upper region  221  provided above the optical axis AX of the exit part  230  and a lower region  222  provided below the optical axis AX of the exit part  230 . 
     Here, the upper region  221  is a region provided in an upper portion of the entrance part  220  with respect to the optical axis AX of the exit part  230  and may have various configurations. 
     Specifically, according to a type and function of the lamp for a vehicle, the upper region  221  may collect the light, which is incident via the upper region  221 , in the vicinity of the focus of the exit part  230 , or may diffuse the light in the vicinity of the focus of the exit part  230 . To this end, the curvature of the upper region  221  may be adjusted according to the purpose such as collection or diffusion of the light. 
     For example, when the upper region  221  is provided to collect the light in the vicinity of the focus of the exit part  230 , the focus of the upper region  221  may correspond to the focus of the exit part  230 . Here, when the upper region  221  and the exit part  230  are anamorphic lenses, the focus of the upper region  221  in the vertical direction may correspond to the focus of the exit part  230  in the vertical direction. Also, when the upper region  221  is provided to diffuse the light in the vicinity of the focus of the exit part  230 , the focus of the upper region  221  may not correspond to the focus of the exit part  230 . Meanwhile, in the specification, a feature in which ‘two focuses correspond to each other’ may be interpreted as including not only a case where the two focuses are completely identical to each other but also a case where two focuses are formed sufficiently close to each other to exhibit substantially the same performance as the case where the two focuses are identical to each other. 
     Meanwhile, the lower region  222  is a region provided in a lower portion of the entrance part  220  with respect to the optical axis AX of the exit part  230  and may have various configurations. 
     Specifically, the lower region  222  may collect the light, which is incident via the lower region  222 , in the vicinity of the focus of the exit part  230 . More specifically, in order to minimize a rate of the light which has been incident via the lower region  222  but does not contribute to a beam pattern because totally reflected by the recessed portion  240 , the light incident from the light source unit  100  may be collected in the vicinity of the focus formed by the exit part  230 . To this end, the focus of the lower region  222  may correspond to the focus of the exit part  230 . Here, when the lower region  222  and the exit part  230  are anamorphic lenses, the focus of the lower region  222  in the vertical direction may correspond to the focus of the exit part  230  in the vertical direction. 
     Meanwhile, the lower region  222  may be configured such that the lower region  222  has large curvature to prevent the light incident parallel to the lower region  222  in the horizontal direction from being blocked by the recessed portion  240 . Therefore, it is possible to increase refractive index of the light that is incident to the lower region  222 . Accordingly, the lower region  222  and the upper region  221  may have different curvature. Specifically, the curvature of the lower region  222  may be greater than the curvature of the upper region  221 . More specifically, the curvature of the lower region  222  in the vertical direction may be greater than the curvature of the upper region  221  in the vertical direction. 
     However, when both the upper region  221  and the lower region  222  have the focuses corresponding to the focus of the exit part  230  to collect the light in the vicinity of the exit part  230 , the upper region  221  and the lower region  222  may have the same curvature. 
     Meanwhile, the exit part  230  is formed on a surface of the body part  210 , from which the light is emitted, and allows the light incident to the body part  210  to be emitted forward. Specifically, the exit part  230  may be formed on the surface that faces the front of the body part  210 . 
     Specifically, the exit part  230  may be formed as various lenses. For example, the exit part  230  may have a shape recessed forward, and may be provided in the form of an aspherical surface lens, an anamorphic lens, or a Fresnel lens that enables reduction in thickness for a degree of freedom in design. 
     Also, the exit part  230  may be integrally formed with the body part  210  and the entrance part  220 . Here, the focus of the exit part  230  may be positioned inside the body part  210  of the lens structure  200 . Specifically, the focus of the exit part  230  may be positioned at a location corresponding to a cut-off edge  242  of the recessed portion  240  which will be described later. 
     Also, in the present disclosure, a focal length L 2  of the exit part  230  may be less than a focal length L 1  of the lower region  222  of the entrance part  220  or equal to the focal length L 1  of the lower region  222 . For example, as illustrated in  FIG.  3   , the focal length L 2  of the exit part  230  is less than the focal length L 1  of the lower region  222  of the entrance part  220 , and thus the light, which is incident from the lower region  222  and collected in the vicinity of the focus of the exit part  230 , may arrive at the exit part  230 . Accordingly, the light incident from the lower region  222  is emitted toward a light distribution region, and thus optical loss may be prevented. 
     Meanwhile, the recessed portion  240 , which serves as a shield of a low beam lamp in the lamp  2  for a vehicle having the above features according to the present disclosure, may have various shapes. 
     For example, the recessed portion  240  may include: a blocking layer  241 ′ for blocking a portion of the light incident to the body part  210 ; and a cut-off edge  242  formed at an upper end of the blocking layer  241 ′ and forming a cut-off line of a low beam pattern. 
     Specifically, the blocking layer  241 ′ may be formed on a first surface  241  adjacent to the entrance part  220 . Also, the blocking layer  241 ′ may extend obliquely downward in a direction toward the light source unit  100  as it goes downward from the cut-off edge  242 , and may block the light which is incident to the lower end of the cut-off edge  242 . Meanwhile, in the drawing, the reference numerals  241  and  241 ′ are illustrated as indicating the same positions. However, the blocking layer  241 ′ is a component formed additionally on the surface of the first surface  241 , and thus it should be noted that the first surface  241  and the blocking layer  241 ′ are distinct concepts. 
     For example, the blocking layer  241 ′ may be formed on the first surface  241  by deposition, and the blocking layer  241 ′ may be made of various materials capable of blocking light. In one example, the blocking layer  241 ′ may be formed on the first surface  241  by depositing an aluminum material to reflect the light. However, the material and formation method of the blocking layer  241 ′ are not limited to those described above, and various materials and methods capable of blocking the light may be employed. 
     The cut-off edge  242  may be formed at the upper end of the blocking layer  241 ′ and provided to form the cut-off line of the low beam pattern. 
     Specifically, the cut-off edge  242  may be connected to the first surface  241  at a first connection portion  244  as illustrated in  FIG.  4   . Here, the first connection portion  244  may represent a line that connects the first surface  241  to the cut-off edge  242 . 
     Also, the cut-off edge  242  may be provided at a position corresponding to the focus of the exit part  230 . In one example, the cut-off edge  242  may be provided at a position corresponding to the focus of the exit part  230 . More specifically, the cut-off edge  242  may be provided to connect the first surface  241  to a second surface  243 . That is, the front end of the cut-off edge  242  may be connected to the second surface  243 , and the rear end of the cut-off edge  242  may be connected to the first surface  241 . Here, the shape of the cut-off edge  242  is not limited, and may be formed diversely according to design specifications for forming a low beam pattern. 
     For example, as illustrated in  FIG.  6   , the cut-off edge  242  may include: a lower cut-off edge  242   b  formed on one side of the left-right direction with respect to a direction from the entrance part  220  toward the exit part  230 ; an upper cut-off edge  242   a  formed on the other side of the left-right direction and provided above the lower cut-off edge  242   b ; and a stepped cut-off edge  242   c  for connecting the lower cut-off edge  242   b  to the upper cut-off edge  242   a . Here, the one side may be the left side when viewed in a direction from the entrance part  220  toward the exit part  230 , and the other side may be the right side when viewed in the direction from the entrance part  220  toward the exit part  230 . However, the one side and the other side described above may be interchanged. 
     Also, the upper cut-off edge  242   a  and the lower cut-off edge  242   b  are parallel to the optical axis AX of the exit part  230 , and the stepped cut-off edge  242   c  are formed obliquely. Thus, the upper cut-off edge  242   a  and the lower cut-off edge  242   b  may be connected to each other with a stepped portion formed therebetween. 
     Also, as described above, the recessed portion  240  may include the second surface  243  that is connected from the cut-off edge  242  at a second connection portion  245  and extends. Here, the second surface  243  may be a portion for connecting the cut-off edge  242  to the lower surface  212  that is adjacent to the exit part  230  among the lower surface  212  provided in the lens structure  200 , and the second connection portion  245  may represent a line that connects the cut-off edge  242  to the second surface  243 . 
     Meanwhile, when parallel light having an angle in the horizontal direction (hereinafter, referred to as ‘horizontal off-axis light’) is incident to the lens structure  200 , the positions of the focuses may be formed differently for each color of light and become inconsistent with the cut-off edge  242  having a line shape that exists on one plane. As a result, light blur due to aberration may occur. Such light blur may cause glare to drivers in oncoming vehicles and pedestrians, thereby obstructing their views, which may lead to traffic accidents. 
     Thus, the second connection portion  245  according to the present disclosure may include a curved connection portion  245   a  and a linear connection portion  245   b  formed on both sides of the curved connection portion  245   a . Specifically, the second connection portion  245  is configured such that the curved connection portion  245   a  is formed at the center in the left-right direction when the lens structure  200  is viewed from above. The linear connection portion  245   b  is formed on both sides of the curved connection portion  245   a  and may be symmetric in the left-right direction with respect to the center of the lens structure  200 . Hereinafter, the curved connection portion  245   a  will be described in more detail. 
     For example, horizontal off-axis light, which may be incident to the lens structure  200 , will be described first in detail with reference to  FIG.  5   . For example, in the horizontal off-axis light, the red light R may be horizontal to the optical axis, green light G may form an angle of about 5 degrees with the optical axis, blue light B may form an angle of about 10 degrees with the optical axis, and black light K may form an angle of about 20 degrees with the optical axis. Thus, the horizontal off-axis light has various angles in the horizontal direction according to colors of the light, and the positions of focuses Rf, Gf, Bf, and Kf for colors may also be formed differently. That is, with regard to the horizontal off-axis light, a focus is not formed on a single plane or straight line, but focuses are formed along a curved surface or curved line. 
     Thus, the second connection portion  245  according to the present disclosure may include the curved connection portion  245   a  having certain curvature as illustrated in  FIG.  4   . Through this, a low beam pattern is formed by changing the angle of light that may cause light blur, and it is possible not only to increase optical efficiency but also to prevent glare for an oncoming vehicle. Here, the certain curvature may represent curvature having a shape which corresponds to a virtual line that connects the plurality of focuses Rf, Gf, Bf, and Kf formed for colors of the horizontal off-axis light as illustrated in  FIG.  5   . The curved connection portion  245   a  may be preferably formed along the positions of the plurality of focuses Rf, Gf, Bf, and Kf. 
     Also, the curved connection portion  245   a  may have a shape recessed in a direction from the exit part  230  toward the entrance part  220 . Here, the recessed shape may represent a portion of a circular or elliptical shape. 
     Meanwhile, the second surface  243  may include a vertical surface  243   a , a horizontal surface  243   b , and an inclined surface  243   c . When described in detail, the vertical surface  243   a  is connected to the cut-off edge  242  at the second connection portion  245  described above and vertically extends downward from the second connection portion  245 , and thus may have the vertical direction that corresponds to the shape of the second connection portion  245 . Here, when the second connection portion  245  includes the curved connection portion  245   a  and the linear connection portion  245   b  and the curved connection portion  245   a  has a shape recessed in the direction from the exit part  230  toward the entrance part  220  as illustrated in  FIG.  4   , the vertical surface  243   a  of the second surface  243  may also have a surface that is recessed rearward so as to correspond to the recessed shape of the curved connection portion  245   a.    
     Also, the horizontal surface  243   b  may be a surface that is connected to the vertical surface  243   a  and extends horizontally in the direction from the entrance part  220  toward the exit part  230 , and the inclined surface  243   c  may be connected to the vertical surface  243   a  and the horizontal surface  243   b  and inclined downward in the direction from the entrance part  220  toward the exit part  230 . 
     Meanwhile, when the cut-off edge  242  having the stepped shape as described above is provided, the first connection portion  244  for connecting the first surface  241  to the cut-off edge  242  and the second connection portion  245  for connecting the cut-off edge  242  to the second surface  243  may also have stepped shapes. Hereinafter, the stepped shape of the second connection portion  245  will be described in detail. 
     As described above, the second connection portion  245  may include the curved connection portion  245   a  and the linear connection portions  245   b . Thus, the stepped shape may be formed at the curved connection portion  245   a  that is formed at the center, in the left-right direction, of the second connection portion  245 . The curved connection portion  245   a  may include: an upper curved connection portion  245   aa  formed in a section in which the upper cut-off edge  242   a  of the recessed portion  240  meets the second surface  243 ; and a lower curved connection portion  245   ab  formed in a section in which the lower cut-off edge  242   b  meets the second surface  243 . Also, the curved connection portion  245   a  may further include a stepped curved connection portion  245   ac  formed in a section in which the stepped cut-off edge  242   c  of the recessed portion  240  meets the second surface  243 . 
     In addition, the linear connection portion  245   b  may include: an upper linear connection portion  245   ba  formed in a section in which the upper cut-off edge  242   a  of the recessed portion  240  meets the second surface  243 ; and a lower linear connection portion  245   bb  formed in a section in which the lower cut-off edge  242   b  meets the second surface  243 . 
     Hereinafter, an effect of enhancing optical efficiency of the lamp for a vehicle according to the present disclosure will be described with reference to  FIG.  7   .  FIG.  7    shows the total light amount (lm) and maximum luminous intensity (cd) of a light distribution pattern formed by the lamp  1  for a vehicle according to the related art (hereinafter, referred to as a ‘comparative example’) and the total light amount (lm) and maximum luminous intensity (cd) of a light distribution pattern formed by the lamp  2  for a vehicle according to the present disclosure (hereinafter, referred to as an ‘exemplary embodiment’). 
     First, when examining the low beam light distribution pattern formed in the comparative example, it can be seen that the total light amount (lm) and maximum luminous intensity (cd) are 119 lm and 2870 cd, respectively. On the other hand, when examining the low beam light distribution pattern formed in the exemplary embodiment, it is found that the total light amount (lm) and maximum luminous intensity (cd) are 129 lm and 3150 cd, respectively. That is, in the exemplary embodiment compared to the comparative example, it is found that the total light amount (lm) increases by about 8%, and the maximum luminous intensity (cd) increases by about 9%. As described above, it is found that the lamp for a vehicle according to the exemplary embodiment of the present disclosure may have the increased total light amount (lm) and maximum luminous intensity (cd) and thus enhance optical efficiency. 
     Hereinafter, a light distribution pattern of a lamp for a vehicle according to the presence or absence of the curved connection portion  245   a  will be described with reference to  FIG.  8   . Part (a) of  FIG.  8    illustrates a low beam light distribution pattern formed by a lamp for a vehicle in which the curved connection portion  245   a  is not included (hereinafter, referred to as a ‘comparative example’), and Part (b) of  FIG.  8    illustrates a low beam light distribution pattern formed by a lamp for a vehicle according to the present disclosure in which the curved connection portion  245   a  is included (hereinafter, referred to as an ‘exemplary embodiment according to the present disclosure’). 
     First, when examining the light distribution pattern formed by the comparative example of Part (a) of  FIG.  8   , it can be seen that light distribution patterns are formed above the left and right sides of a cut-off line CL. The light distribution patterns formed above the cut-off line CL may cause glare to drivers in oncoming vehicles or pedestrians, thereby obstructing their views. On the other hand, with respect to the light distribution patterns formed by the exemplary embodiment of the present disclosure in Part (b) of  FIG.  8   , it can be seen that light distribution patterns are not formed above the left and right sides of a cut-off line CL. In particular, it can be seen that a light distribution pattern is not formed in a region B above the right side of the cut-off line CL. Therefore, the light distribution pattern formed according to the exemplary embodiment of the present disclosure may sufficiently secure the front view without obstructing the views of the drivers in oncoming vehicles or pedestrians, thereby significantly reducing the risk of accidents. 
     Meanwhile, the present disclosure may provide a vehicle that includes a lamp for a vehicle, the lamp including: a light source unit  100  emitting light; and a lens structure  200  which is located in front of the light source unit  100  and projects the light emitted from the light source unit  100  to form a certain beam pattern. The lens structure  200  includes: a body part  210 ; an entrance part  220  which is formed on a surface of the body part  210 , to which the light is incident, and allows the light emitted from the light source unit  100  to be incident to the body part  210 ; and an exit part  230  which is formed on a surface of the body part  210 , from which the light is emitted, and allows the light incident to the body part  210  to be emitted forward. The body part  210  includes a recessed portion  240  which is recessed toward a central region, in the up-down direction, of the body part  210 , and the recessed portion  240  blocks the light, which is emitted from the light source unit  100  and arrives at the recessed portion  240 . The entrance part  220  includes an upper region  221  and a lower region  222  which are provided in an upper portion and a lower portion, respectively, with respect to an optical axis of the exit part  230 , and curvature of the upper region  221  is different from curvature of the lower region  222 . 
     Meanwhile, the contents described above with respect to the lamp according to the present disclosure may also be applied, in the same manner, to the vehicle according to the present disclosure. 
     In the lamp for the vehicle according to the exemplary embodiment of the present disclosure, the entrance part is made of the upper and lower regions having different curvature, and the curvature of the lower region in the vertical direction is greater than the curvature of the upper region in the vertical direction. Therefore, the optical efficiency may be enhanced by minimizing the loss of light incident to the lower region. 
     Also, in the lamp for the vehicle according to the exemplary embodiment of the present disclosure, the focal length of the exit part is equal to the focal length of the lower region of the entrance part or less than the focal length of the lower region of the entrance part. Therefore, the optical loss may be minimized by preventing the incident light from being trapped inside the lens structure or the optical path from being changed to the non-light distribution region. 
     Although the specific exemplary embodiments of the present disclosure have been described, the concept and scope of the present disclosure are not limited to theses specific exemplary embodiments. Various changes and modifications may be made by one skilled in the art to which the present disclosure pertains without departing from the subject matters of the present disclosure as hereinafter claimed.