Light source module for vehicular front headlight

Abstract

A light source module (1) for a vehicular front headlight includes: a single light source (10); and a single light-guide member (20) that includes, integrally, a plurality of total reflectance surfaces and a plurality of emission surfaces. Each of the total reflectance surfaces is configured so as to totally reflect the light from the single light source (10) towards the respectively corresponding emission surfaces.

Description

Light source module for vehicle headlights

[0001] The present disclosure relates to a light source module for a vehicle headlamp.

[0002] Due to requirements for vehicle exterior design, vehicle headlights that are wide in the left-right direction and narrow in the up-down direction are becoming popular. In order to realize vehicle headlights of this shape, Patent Document 1 and the like discloses the use of a light guide member that is integrally provided with a reflective surface and a refracting surface.

[0003] International Publication No. 2017 / 185118

[0004] The light source module described in Patent Document 1 is configured so that light emitted from a single light source illuminates a single illumination area through a single emission surface. However, with a small light guide member measuring at most about 10 cm, it is difficult to sufficiently diffuse the light emitted from the light source in the left-right direction. Therefore, in order to achieve a wide low-beam light distribution pattern, it is necessary to prepare multiple light source modules and precisely align the optical axes of these light source modules, which is not practical.

[0005] Therefore, an object of the present disclosure is to provide a light source module for a vehicle headlamp that can easily obtain a desired light distribution pattern even when a relatively small light guide member is used.

[0006] A light source module for a vehicle headlight according to one aspect of the present disclosure is a light source module for a vehicle headlight comprising: a single light source; and a single light guide member integrally having a plurality of total reflection surfaces and a plurality of exit surfaces, wherein each of the total reflection surfaces is configured to totally reflect light from the single light source toward the corresponding exit surface.

[0007] According to the present disclosure, a light guide member is provided with multiple exit surfaces and total reflection surfaces that reflect light toward each of the exit surfaces, allowing for the design of illumination areas independently of each other using optical systems consisting of each total reflection surface and exit surface. Because the multiple exit surfaces and multiple total reflection surfaces are integrally formed on the light guide member, it is easy to improve positional accuracy and shape accuracy. Therefore, a light source module that can easily obtain a desired light distribution pattern even when a relatively small light guide member is used can be provided.

[0008] According to the present disclosure, a light source module for a vehicle headlamp is provided that can easily obtain a desired light distribution pattern even when a relatively small light guide member is used.

[0009] FIG. 1 is a perspective view from above illustrating a light source module of a vehicle headlamp according to a first embodiment. FIG. 2 is a perspective view from below of the light source module of FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a perspective view from above illustrating a light source module of a vehicle headlamp according to a first modified example. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4. FIG. 6 is a perspective view from above illustrating a light source module of a vehicle headlamp according to a second modified example. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For the sake of convenience, descriptions of components having the same reference numerals as those already described in the description of the embodiments will be omitted. Furthermore, for the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0011] Furthermore, in the description of this embodiment, for convenience of explanation, the terms "left-right direction," "up-down direction," and "front-rear direction" may be referred to as appropriate. These directions are relative directions set for the light source module 1 of the vehicle headlight exemplified in FIGS. 1 and 2. Here, the "left-right direction" includes the "left direction" and the "right direction," and is also the vehicle width direction of the vehicle on which the light source module 1 of the vehicle headlight is mounted. The "up-down direction" includes the "upward direction" and the "downward direction." The "front-rear direction" is the front-rear direction of the vehicle and includes the "forward direction" and the "rearward direction." The front-rear direction is a direction perpendicular to the left-right direction and the up-down direction. Note that in each figure, the symbol U indicates the upward direction. The symbol D indicates the downward direction. The symbol F indicates the forward direction. The symbol B indicates the rearward direction. The symbol L indicates the leftward direction. The symbol R indicates the rightward direction. The left-right direction is an example of the horizontal direction.

[0012] First Embodiment A light source module 1 for a vehicle headlamp according to a first embodiment will be described with reference to Figures 1 to 3. The light source module 1 is mounted in a vehicle headlamp and configured to form at least a low-beam light distribution pattern.

[0013] Fig. 1 is a perspective view illustrating a light source module 1 for a vehicle headlamp according to this embodiment, as seen from above. Fig. 2 is a perspective view of the light source module 1 as seen from below. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. As illustrated in Figs. 1 to 3, the light source module 1 for a vehicle headlamp includes a single light source 10 and a single light guide member 20.

[0014] As illustrated in Fig. 2, the light source 10 is provided on the back side of the light guide member 20. The light source 10 is, for example, an LED (Light Emitting Diode) element or an LD (Laser Diode) element. The light source 10 is provided so as to emit light forward. The light output surface of the light source 10 is provided so as to face forward.

[0015] The light guide member 20 is made of a transparent material that transmits light, and is configured to guide the light emitted from the light source 10 toward the front of the vehicle.

[0016] The light guide member 20 integrally includes a plurality of incident surfaces 21, a plurality of total reflection surfaces 22, a cutoff line forming portion 23, and a plurality of exit surfaces 24.

[0017] The incident surface 21 is a surface onto which light emitted from the light source 10 is incident. The incident surface 21 has a first incident surface 211 and a second incident surface 212. The first incident surface 211 and the second incident surface 212 form a recess that is convex forward on the back surface of the light guide member 20. The light source 10 is provided in this recess.

[0018] The second incident surface 212 is provided at a position directly opposite the exit surface of the light source 10 in the front-rear direction. The second incident surface 212 forms a lens surface that is convex toward the rear. The second incident surface 212 is configured to refract light from the light source 10 toward a front exit surface 242 (described later), which is different from the exit surface 24 to which the total reflection surface 22 directs the light. In this embodiment, as illustrated in FIG. 3 , the second incident surface 212 refracts the light from the light source 10 so that the light from the light source 10 is focused in front of the front exit surface 242.

[0019] 2, the first incident surface 211 is a curved surface extending from the second incident surface 212 toward the rear end surface 20B of the light guide member 20. The first incident surface 211 is configured with a substantially conical side surface that tapers toward the front and partially surrounds the light source 10. The second incident surface 212 is provided on the tip side of the cone.

[0020] 3, first left and right incident surfaces 211L and 211R facing each other in the left-right direction appear as first incident surfaces 211. First incident surfaces 211 are configured to refract light from light source 10 toward corresponding regions of total reflection surface 22. In this embodiment, first left incident surface 211L is located to the left of light source 10. First right incident surface 211R is located to the right of light source 10.

[0021] 2 , a cutout C, in which the first incident surface 211 is not formed, may be formed in the lower rear portion of the light guide member 20. The cutout C prevents light traveling downward from the light source 10 from entering the light guide member 20, thereby preventing stray light from being unintentionally totally reflected on the surface (lower surface) of the light guide member 20 and traveling upward in the vehicle.

[0022] The plurality of light exit surfaces 24 are provided on the front surface of the light guide member 20. Each light exit surface 24 forms a single lens surface that is convex toward the front. The lens surfaces of the light exit surfaces 24 may be the same as or different from each other.

[0023] The light exit surface 24 has a plurality of first light exit surfaces 241 and a front light exit surface 242. In this embodiment, the first light exit surfaces 241 and the front light exit surfaces 242 are arranged in the left-right direction. More specifically, the front light exit surface 242 is located between two first light exit surfaces 241 in the left-right direction.

[0024] The front exit surface 242 is provided at a position directly opposite the second incident surface 212 in the front-rear direction. The front exit surface 242 is configured to irradiate light incident on the second incident surface 212 forward. The first exit surface 241 has a first left exit surface 241L and a first right exit surface 241R. The first left exit surface 241L is located to the left of the front exit surface 242. The first left exit surface 241L is configured to irradiate light incident on the first left incident surface 211L forward. The first right exit surface 241R is located to the right of the front exit surface 242. The first right exit surface 241R is configured to irradiate light incident on the first right incident surface 211R forward.

[0025] The total reflection surfaces 22 are provided behind the emission surfaces 24. The total reflection surfaces 22 are provided on the back surface of the light guide member 20. The total reflection surfaces 22 are configured to totally reflect the light from the light source 10 toward the emission surfaces 24. In this embodiment, one total reflection surface 22 faces one emission surface 24 in the front-to-rear direction.

[0026] In this embodiment, the total reflection surface 22 has a left total reflection surface 22L and a right total reflection surface 22R. The left total reflection surface 22L is located to the left of the first left incident surface 211L. The left total reflection surface 22L is configured to focus light incident on the first left incident surface 211L from the light source 10 at a focal point FL2 and to totally reflect the light toward the first left exit surface 241L. The right total reflection surface 22R is located to the right of the first right incident surface 211R. The right total reflection surface 22R is configured to focus light incident on the first right incident surface 211R from the light source 10 at a focal point FR2 and to totally reflect the light toward the first right exit surface 241R. In other words, the multiple total reflection surfaces 22L, 22R are configured to totally reflect the light from the light source 10 toward the corresponding exit surfaces 24.

[0027] Each of the plurality of cutoff line forming portions 23 is configured to totally reflect a portion of light traveling from the corresponding incident surface 21 toward the corresponding exit surface 24, thereby preventing the light from emitting above the irradiation area. The plurality of cutoff line forming portions 23 may be configured to totally reflect a portion of light that is about to enter the first exit surface 241, by a total reflection surface extending rearward of the cutoff line forming portion 23, thereby preventing the light from emitting above the irradiation area. A cutoff line of the low beam light distribution pattern is formed by blocking a portion of the light by the cutoff line forming portion 23.

[0028] The cutoff line forming portion 23 is a step portion provided on the lower surface of the light guide member 20 (FIGS. 1 and 2). The front portion of the lower surface of the light guide member 20 protrudes downward more than the rear portion. The cutoff line forming portion 23 is located at the boundary between the front and rear portions of the lower surface of the light guide member 20. When viewed from the front, the cutoff line forming portion 23 has a shape that corresponds to the cutoff line of the low beam distribution pattern. All of the multiple cutoff line forming portions 23 provided on the light guide member 20 have the same shape.

[0029] The cutoff line forming portion 23 has a plurality of first cutoff line forming portions 231 and a second cutoff line forming portion 232. In the present embodiment, the plurality of first cutoff line forming portions 231 and the second cutoff line forming portions 232 are arranged in the left-right direction. More specifically, the second cutoff line forming portion 232 is located between the two first cutoff line forming portions 231 in the left-right direction.

[0030] The second cutoff line forming portion 232 is located between the second incident surface 212 and the front emission surface 242. The second cutoff line forming portion 232 is configured to totally reflect a part of the light traveling from the second incident surface 212 toward the front emission surface 242.

[0031] The first cutoff line forming portion 231 has a first left cutoff line forming portion 231L and a first right cutoff line forming portion 231R.

[0032] The first left cutoff line forming portion 231L is located between the first left incident surface 211L and the first left exit surface 241L. The first left cutoff line forming portion 231L is configured to totally reflect a part of the light traveling from the first left incident surface 211L toward the first left exit surface 241L.

[0033] The first right cutoff line forming portion 231R is located between the first right incident surface 211R and the first right exit surface 241R. The first right cutoff line forming portion 231R is configured to totally reflect a part of the light traveling from the first right incident surface 211R toward the first right exit surface 241R.

[0034] In this way, the light guide member 20 integrally includes multiple optical systems. More specifically, the light guide member 20 includes three optical systems arranged in the left-right direction. The light guide member 20 includes multiple first optical systems OS1 and second optical systems OS2. In the left-right direction, the second optical system OS2 is located between two first optical systems OS1.

[0035] The second optical system OS2 is composed of a second incident surface 212, a second cutoff line forming portion 232, and a front exit surface 242. The first optical system OS1 has a first left optical system OS1L and a first right optical system OS1R. The first left optical system OS1L is composed of a first left incident surface 211L, a first left cutoff line forming portion 231L, and a first left exit surface 241L. The first right optical system OS1R is composed of a first right incident surface 211R, a first right cutoff line forming portion 231R, and a first right exit surface 241R.

[0036] The length L10 of the first left optical system OS1L in the front-rear direction is the same as the length L10 of the first right optical system OS1R in the front-rear direction. In this embodiment, the "length of the optical system" refers to the length in the front-rear direction from the rear end of the entrance surface of the optical system to the front end of the exit surface.

[0037] Next, the way in which light travels will be described. Fig. 3 illustrates an example of how light emitted from light source 10 passes through the inside of light guide member 20 and is emitted forward. For convenience of explanation, the relatively high-intensity light emitted from light source 10 at an emission angle smaller than a predetermined angle will be referred to as L2, and the relatively low-intensity light emitted from light source 10 at an emission angle equal to or greater than the predetermined angle will be referred to as L1.

[0038] First, the travel of light L2 will be described. As illustrated in FIG. 3 , a portion of light L2 emitted from the light source 10 is incident on the second incident surface 212 and guided into the light guide member 20. The light L2 is refracted by the lens surface of the second incident surface 212, passes near the second cutoff line forming portion 232, and reaches the front emission surface 242. When the light L2 passes near the second cutoff line forming portion 232, a portion of the light L2 is totally reflected by the second cutoff line forming portion 232 and reaches the front emission surface 242. The remaining portion of the light L2 that is not totally reflected by the second cutoff line forming portion 232 and passes above the second cutoff line forming portion 232 also reaches the front emission surface 242.

[0039] Because light L2 that has passed above the second cutoff line forming portion 232 and light L2 that has been totally reflected by the second cutoff line forming portion 232 reach the front exit surface 242, the front exit surface 242 forms a low-beam light distribution pattern in which the upper portion is light-shielded and the lower portion is light-irradiated. Since the second cutoff line forming portion 232, which has a region that transmits light and a boundary that totally reflects light, has a stepped shape when viewed from the front, a step-shaped cutoff line is formed between the bright and dark portions of the low-beam light distribution pattern. In this way, the light guide member 20 forms a part of the low-beam light distribution pattern by the second incident surface 212, the second cutoff line forming portion 232, and the front exit surface 242.

[0040] The light guide member 20 is configured so that the light L2 totally reflected by the second cutoff line forming portion 232 is incident on the front light exit surface 242, and the light is irradiated onto an area below the cutoff line of the low-beam light distribution pattern. This improves the light utilization efficiency.

[0041] Next, the way in which light L1 travels will be described. Here, the way in which light L1 travels that is emitted to the left from the light source 10 will be described. The way in which light L1 travels that is emitted to the right from the light source 10 is the same as the way in which light L1 travels that is emitted to the left from the light source 10, so the explanation will be omitted.

[0042] 3 , a portion of light L1 emitted leftward from the light source 10 is incident on the first left incident surface 211L and guided into the light guide member 20. The light L1 is refracted by the lens surface of the first left incident surface 211L and guided to the left total reflection surface 22L. The light L1 that reaches the left total reflection surface 22L is totally reflected by the left total reflection surface 22L, passes near the first left cutoff line forming portion 231L, and reaches the first left exit surface 241L. As with the second cutoff line forming portion 232, a portion of the light L1 that is totally reflected by the first left cutoff line forming portion 231L and another portion of the light that passes above the first left cutoff line forming portion 231L without being totally reflected reaches the first left exit surface 241L. In this manner, the light guide member 20 forms a part of a low-beam light distribution pattern by the first left incident surface 211L, the first left cutoff line forming portion 231L, and the first left exit surface 241L.

[0043] Similarly, the light guide member 20 forms a low-beam light distribution pattern by the first right incident surface 211R, the first right cutoff line forming portion 231R, and the first right exit surface 241R.

[0044] The light source module 1 forms a low-beam light distribution pattern forward using a part of the low-beam light distribution pattern formed by the light L2 and a part of the low-beam light distribution pattern formed by the light L1.

[0045] As described above, the light source module 1 for a vehicle headlamp according to this embodiment includes a single light source 10 and a single light guide member 20 integrally having multiple total reflection surfaces and multiple exit surfaces. Each total reflection surface is configured to totally reflect light from the single light source 10 toward its corresponding exit surface. This allows the optical systems formed by the respective total reflection surfaces and exit surfaces to design their illumination areas independently of each other. For example, the left optical system formed by the left total reflection surface 22L and the first left exit surface 241L and the right optical system formed by the right total reflection surface 22R and the first right exit surface 241R can be designed independently of each other. This makes it easy to form a desired light distribution pattern.

[0046] Furthermore, in the light source module 1 of this embodiment, the multiple light exit surfaces and the multiple total reflection surfaces are integrally formed on the light guide member 20. Therefore, it is easier to improve the positional accuracy and shape accuracy compared to when the light exit surfaces and the total reflection surfaces are formed on different members. As a result, the light source module 1 is provided that can easily obtain a desired light distribution pattern even when a relatively small light guide member 20 is used.

[0047] The light guide member 20 of this embodiment has a first left incident surface 211L, a first right incident surface 211R, and a second incident surface 212 provided at a position directly facing the light source 10. The first left incident surface 211L is configured to refract light from the light source 10 toward the corresponding left total reflection surface 22L. The first right incident surface 211R is configured to refract light from the light source 10 toward the corresponding right total reflection surface 22R. The second incident surface 212 is configured to refract light from the light source 10 toward the front exit surface 242. Because the light emitted from the light source 10 is incident on the first left incident surface 211L, the first right incident surface 211R, and the second incident surface 212 in this manner, the luminous flux utilization efficiency can be improved.

[0048] The first light exit surface 241 and the front light exit surface 242 are arranged in the left-right direction. This allows a wide light distribution pattern to be formed in the left-right direction. Furthermore, the light guide member 20 can be formed to have a narrow width in the up-down direction, which improves the mountability in a vehicle headlamp.

[0049] The plurality of total reflection surfaces 22 may be formed of free-form surfaces independent of each other. For example, the left total reflection surface 22L and the right total reflection surface 22R may have different free-form surfaces. With this configuration, light guide member 20 can easily focus light from a single light source 10 onto focal points FL2 and FR2, respectively, increasing the degree of freedom in designing each optical system.

[0050] The plurality of total reflection surfaces 22 may not be rotationally symmetric with respect to the optical axis AX of the light source 10. From the viewpoint of focusing the light from the light source 10 at a single focal point, it is also possible to form the plurality of total reflection surfaces 22 rotationally symmetric with respect to the optical axis AX of the light source 10. In this case, although the difficulty of molding the light guide member 20 decreases, it becomes more difficult to freely design each optical system. In this embodiment, the left total reflection surface 22L and the right total reflection surface 22R are formed as curved surfaces that are not rotationally symmetric with respect to the optical axis AX of the light source 10. The left total reflection surface 22L and the right total reflection surface 22R may be formed symmetrically in the left-right direction, for example. In such a case, it becomes easier to focus the light from the light source 10 at each of the focal points FL2 and FR2, thereby increasing the degree of freedom in designing the optical system.

[0051] The focal point of each total reflection surface 22 is located forward of the focal point of the corresponding exit surface 24 ( FIG. 3 ). In this embodiment, the focal point FL2 of the left total reflection surface 22L is located forward of the focal point FL4 of the corresponding first left exit surface 241L. Therefore, the first left optical system OS1L can form a light distribution pattern that is diffused in the left-right direction. Furthermore, the focal point FR2 of the right total reflection surface 22R is located forward of the focal point FR4 of the corresponding first right exit surface 241R. Therefore, the first right optical system OS1R can form a light distribution pattern that is diffused in the left-right direction.

[0052] (First Modification) In the first embodiment described above, the plurality of first incident surfaces 211 and second incident surfaces 212 are arranged in the left-right direction, but the arrangement direction of the plurality of incident surfaces is not limited to the left-right direction. The plurality of first incident surfaces 211 and second incident surfaces 212 may also be arranged in the up-down direction.

[0053] Fig. 4 is a perspective view from above illustrating a light source module 1X for a vehicle headlamp according to a first modified example. Fig. 5 is a cross-sectional view taken along line V-V in Fig. 4. In the configuration shown in Fig. 4, the same components as those shown in Fig. 1 are designated by the same reference numerals, and their description will be omitted. In the configuration shown in Fig. 5, the same components as those shown in Fig. 3 are designated by the same reference numerals, and their description will be omitted.

[0054] As illustrated in FIGS. 4 and 5, a light source module 1X for a vehicle headlamp includes a single light source 10 and a single light guide member 20X.

[0055] 5 , a first upper incident surface 211U and a first lower incident surface 211D that face each other in the up-down direction appear as the first incident surface 211. In this modification, the first upper incident surface 211U is located above the light source 10. The first lower incident surface 211D is located below the light source 10.

[0056] In this modification, first light exit surface 241 and front light exit surface 242 are arranged in the vertical direction. More specifically, front light exit surface 242 is located between two first light exit surfaces 241 in the vertical direction.

[0057] The first exit surface 241 has a first upper exit surface 241U and a first lower exit surface 241D. The first upper exit surface 241U is located higher than the front exit surface 242. The first upper exit surface 241U is configured to direct light that has entered the first upper incident surface 211U forward to form part of a low-beam light distribution pattern. The first lower exit surface 241D is located lower than the front exit surface 242. The first lower exit surface 241D is configured to direct light that has entered the first lower incident surface 211D forward to form part of a low-beam light distribution pattern.

[0058] The total reflection surface 22 has an upper total reflection surface 22U and a lower total reflection surface 22D. The upper total reflection surface 22U is located above the first upper incident surface 211U. The upper total reflection surface 22U is configured to focus light incident on the first upper incident surface 211U from the light source 10 at a focal point FU2 and to totally reflect the light toward the first upper exit surface 241U. The lower total reflection surface 22D is located below the first lower incident surface 211D. The lower total reflection surface 22D is configured to focus light incident on the first lower incident surface 211D from the light source 10 at a focal point FD2 and to totally reflect the light toward the first lower exit surface 241D.

[0059] The first cutoff line forming portion 231 has a first upper cutoff line forming portion 231U and a first lower cutoff line forming portion 231D. The first upper cutoff line forming portion 231U is located between the first upper incident surface 211U and the first upper exit surface 241U. The first upper cutoff line forming portion 231U is configured to totally reflect a portion of light traveling from the first upper incident surface 211U to the first upper exit surface 241U. The first lower cutoff line forming portion 231D is located between the first lower incident surface 211D and the first lower exit surface 241D. The first lower cutoff line forming portion 231D is configured to totally reflect a portion of light traveling from the first lower incident surface 211D to the first lower exit surface 241D.

[0060] In this manner, the light guide member 20X has a plurality of first optical systems OS1 and second optical systems OS2 arranged in the vertical direction.

[0061] The first optical system OS1 has a first upper optical system OS1U and a first lower optical system OS1D. The first upper optical system OS1U is composed of a first upper incident surface 211U, a first upper cutoff line forming portion 231U, and a first upper exit surface 241U. The first lower optical system OS1D is composed of a first lower incident surface 211D, a first lower cutoff line forming portion 231D, and a first lower exit surface 241D.

[0062] Next, the way in which light L1 travels will be described with reference to Figure 5. The way in which light L2 travels in this modified example is the same as the way in which light L2 travels in the first embodiment, and therefore a description thereof will be omitted. Here, the way in which light L1 emitted upward from the light source 10 travels will be described. The way in which light L1 emitted downward from the light source 10 travels is the same as the way in which light L1 emitted upward from the light source 10, and therefore a description thereof will be omitted.

[0063] 5 , a portion of light L1 emitted upward from light source 10 is incident on first upper incident surface 211U and guided into light guide member 20. Light L1 is refracted by the lens surface of first upper incident surface 211U and guided to upper total reflection surface 22U. Light L1 that reaches upper total reflection surface 22U is totally reflected by upper total reflection surface 22U, passes near first upper cutoff line forming portion 231U, and reaches first upper exit surface 241U. At this time, a portion of light L1 is totally reflected by first upper cutoff line forming portion 231U and reaches first upper exit surface 241U, and another portion of light L1 that passes above first upper cutoff line forming portion 231U without being totally reflected also reaches first upper exit surface 241U. In this manner, the light guide member 20X forms a part of a low-beam light distribution pattern by the first upper incident surface 211U, the first upper cutoff line forming portion 231U, and the first upper exit surface 241U.

[0064] Similarly, the light guide member 20X forms a part of a low-beam light distribution pattern by the first lower incident surface 211D, the first lower cutoff line forming portion 231D, and the first lower exit surface 241D.

[0065] As described above, in the light source module 1X according to this modification, the first light exit surface 241 and the front light exit surface 242 are arranged in the vertical direction, which makes it easier to mount the light source module 1X in a limited space inside a vehicle that expands in the vertical direction.

[0066] (Second Modification) In the first embodiment and the first modification described above, the lengths of the optical systems in the front-rear direction are the same, but the lengths of the optical systems may be different from each other.

[0067] Fig. 6 is a perspective view from above illustrating a light source module 1Y for a vehicle headlamp according to a second modified example. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. In the configuration shown in Fig. 6, the same components as those shown in Fig. 4 are designated by the same reference numerals, and their description will be omitted. In the configuration shown in Fig. 7, the same components as those shown in Fig. 5 are designated by the same reference numerals, and their description will be omitted.

[0068] As illustrated in Figures 6 and 7, the light source module 1Y for a vehicle headlamp includes a single light source 10 and a single light guide member 20Y. The light guide member 20Y has a first upper optical system OS1U, a first lower optical system OS1D, and a second optical system OS2, arranged in the vertical direction. The length L10U of the first upper optical system OS1U in the front-rear direction is different from the length L10D of the first lower optical system OS1D in the front-rear direction. More specifically, the length L10D of the first lower optical system OS1D in the front-rear direction is longer than the length L10U of the first upper optical system OS1U in the front-rear direction. The first upper optical system OS1U is an example of a diffusing optical system. The first lower optical system is an example of a converging optical system. In the first upper optical system OS1U, the first upper exit surface 241UY may be formed of a cylindrical lens.

[0069] As described above, according to this modification, by changing the length of each optical system in the longitudinal direction, it is easy to mount the light source module 1Y in the limited space inside the vehicle. Furthermore, since the length L10D of the first lower optical system OS1D is longer than the length L10U of the first upper optical system OS1U in the longitudinal direction, it is easy to provide the light source module 1Y suitable for a vehicle lamp having a lamp chamber whose longitudinal dimension increases downward.

[0070] The first upper exit surface 241UY of the first upper optical system OS1U is a cylindrical lens, which can diffuse the light from the light source 10 more widely in the left-right direction than when the first upper exit surface 241UY is formed by a convex lens.

[0071] Although the embodiments of the present disclosure have been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the disclosure described in the claims. The technical scope of the present disclosure should be determined based on the scope of the disclosure described in the claims and its equivalents.

[0072] In the above-described embodiment and modified examples, the light source modules 1, 1X, and 1Y are all configured to form a low-beam light distribution pattern, but each light source module may be configured to form a high-beam light distribution pattern. In this case, each light source module does not include the cutoff line forming portion 23, and light from the light source 10 is guided to the multiple emission surfaces 24 and emitted forward of the vehicle without being totally reflected by the cutoff line forming portion 23.

[0073] The configurations described in the following items also constitute part of the present disclosure. Item 1: A light source module for a vehicle headlamp, comprising: a single light source; and a single light guide member integrally having a plurality of total reflection surfaces and a plurality of exit surfaces, wherein each of the total reflection surfaces is configured to totally reflect light from the single light source toward the corresponding one of the exit surfaces. Item 2: The light source module according to Item 1, wherein the plurality of total reflection surfaces are formed by free-form surfaces independent of each other. Item 3: The light source module according to Item 1 or 2, wherein the plurality of total reflection surfaces are not rotationally symmetric with respect to the optical axis of the light source. Item 4: The light source module according to any one of Items 1 to 3, wherein a focal point of the total reflection surface is located forward of a focal point of the corresponding one of the exit surfaces. Item 5: The light source module according to any one of Items 1 to 4, wherein the light guide member integrally has a plurality of optical systems, and wherein the lengths of the plurality of optical systems in the front-to-rear direction are different from one another. Item 6: The light source module according to item 5, wherein the light guide member has a focusing optical system and a diffusing optical system, and the length of the focusing optical system in the front-to-rear direction is longer than the length of the diffusing optical system. Item 7: The light source module according to any one of items 1 to 6, wherein the light guide member has a first incident surface and a second incident surface provided at a position directly facing the light source, and the first incident surface refracts light from the light source toward the corresponding total reflection surface, and the second incident surface refracts light from the light source toward a front exit surface different from the exit surface. Item 8: The light source module according to any one of items 1 to 7, wherein the plurality of exit surfaces are arranged in the left-right direction. Item 9: The light source module according to any one of items 1 to 7, wherein the plurality of exit surfaces are arranged in the up-down direction.

[0074] This application claims priority based on Japanese Application No. 2024-098804, filed on June 19, 2024, and incorporates by reference all of the contents of the aforementioned Japanese application.

Claims

1. A light source module for a vehicle headlamp comprising: a single light source; and a single light guide member integrally having a plurality of total reflection surfaces and a plurality of exit surfaces, wherein each of the total reflection surfaces is configured to totally reflect light from the single light source toward its corresponding exit surface.

2. The light source module according to claim 1, wherein the plurality of total reflection surfaces are formed as free-form surfaces independent of each other.

3. The light source module according to claim 1, wherein the focal point of said total reflection surface is located forward of the focal point of the corresponding light exit surface.

4. The light source module according to claim 1, wherein the light guide member has a plurality of optical systems integrally therewith, and the lengths of the plurality of optical systems in the front-to-rear direction are different from one another.

5. The light source module according to claim 4, wherein the light guide member has a focusing optical system and a diffusing optical system, and the length of the focusing optical system in the front-to-rear direction is longer than the length of the diffusing optical system.

6. The light source module according to claim 1, wherein the light guide member has a first incident surface and a second incident surface provided at a position directly opposite the light source, the first incident surface refracting light from the light source toward the corresponding total reflection surface, and the second incident surface refracting light from the light source toward a front exit surface different from the exit surface.

7. The light source module according to claim 1, wherein the plurality of light exit surfaces are arranged in the left-right direction.

8. The light source module according to claim 1, wherein the plurality of light exit surfaces are arranged in a vertical direction.

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