JP2015079660A - Vehicle lighting appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle lighting appliance which is improved in light utilization efficiency, and reducible in size.SOLUTION: A vehicle lighting appliance 10 comprises a first lens part 12, a second lens part 14, a light guide part 16 and a light source 18 which are arranged in the order from a vehicle front side toward a vehicle rear side, in which light from the light source 18 is guided by the light guide part 16, permeates the second lens part 14 and the first lens part 12 in the order, and then is radiated frontward to form a low-beam light distribution pattern. A lower end edge of an emission face of the light guide part includes a stepped edge part having a shape corresponding to a cut-off line, and is arranged in the vicinity of a reference shaft, the first lens part and the second lens part constitute a projection lens 24 whose focus is located in the vicinity of the stepped edge part, the emission face of the light guide part 16 and an incident face of the second lens part 14 are in surface-contact with each other, and a rear focal plane of the projection lens 24 substantially coincides with the stepped edge part.

Description

  The present invention relates to a vehicular lamp, and more particularly, to a vehicular lamp including a light source and a lens disposed in front of the light source.

  Conventionally, in the field of vehicular lamps, a light source and a lens disposed in front of the light source are provided, and direct light from the light source is transmitted forward through the lens, and the upper edge includes a cut-off line. There has been proposed a vehicular lamp configured to form a beam light distribution pattern (see, for example, Patent Document 1).

  FIG. 8 is a perspective view of the vehicular lamp 200 described in Patent Document 1. FIG.

  As shown in FIG. 8, the vehicular lamp 200 described in Patent Document 1 includes a light source 210, a convex lens 220 disposed in front of the light source 210, and an additional lens 230 disposed so as to surround the convex lens 220. A part of the direct light from the light source 210 (light having a high relative intensity emitted in a narrow-angle direction with respect to the reference axis AX extending in the vehicle front-rear direction) passes through the convex lens 220 and is irradiated forward, and the light source 210 Another part of the direct light from the light (light having a low relative intensity emitted in the wide-angle direction with respect to the reference axis AX) enters the additional lens 230 and is internally reflected inside the additional lens 230 to change the course. Then, the light beam is irradiated forward, and a light distribution pattern for a passing beam including a cut-off line at the upper end edge is formed.

Japanese Patent No. 5196314

  However, in the vehicular lamp 200 having the above-described configuration, another part of the direct light from the light source 210 (light with low relative intensity emitted in the wide-angle direction with respect to the reference axis AX) is used by the action of the additional lens 230. Therefore, although the light use efficiency is improved, the additional lens 230 is disposed so as to surround the convex lens 220, and therefore, there is a problem that the vehicular lamp 200 is correspondingly enlarged.

  This invention is made | formed in view of such a situation, and it aims at providing the vehicle lamp which can improve light utilization efficiency and can be reduced in size.

  In order to achieve the above object, the invention described in claim 1 includes a first lens unit, a second lens unit, a light guide unit, and a light source, which are sequentially arranged from the vehicle front side toward the vehicle rear side, After the light from the light source is guided by the light guide unit, the light is transmitted through the second lens unit and the first lens unit in this order and irradiated forward to form a light distribution pattern for passing beam. In the lamp, the first lens unit and the second lens unit are disposed on a reference axis extending in a vehicle front-rear direction, and the light guide unit receives light from the light source inside the light guide unit. Including an incident surface and an exit surface from which light from the light source incident on the inside of the light guide portion exits, and is disposed above the reference axis, and a lower end edge of the exit surface of the light guide portion is Including a stepped edge portion having a shape corresponding to a cut-off line, The first lens unit and the second lens unit are arranged in the vicinity of each other to form a projection lens whose focal point is positioned in the vicinity of the stepped edge unit, and the light source includes a horizontally long light emitting surface, The horizontally long light emitting surface is disposed above the reference axis and in the vicinity of the reference axis in a state of being opposed to the incident surface in the vicinity of the incident surface of the light guide unit. The incident surface of the lens unit is in surface contact, and the rear focal plane of the projection lens is substantially coincident with the stepped edge portion.

  According to the first aspect of the present invention, it is possible to provide a vehicular lamp that can improve light utilization efficiency and can be miniaturized.

  The light use efficiency is improved because the light source (light emitting surface) is disposed in the vicinity of the incident surface of the light guide unit in a state facing the incident surface, so that almost all of the light from the light source (light emitting surface) This is because the light enters the light guide from the incident surface of the light guide.

  The downsizing is possible because the light utilization efficiency can be improved without using the additional lens described in the prior art (for example, Japanese Patent No. 5196314).

  According to a second aspect of the present invention, in the first aspect of the present invention, the first lens unit has a planar optical surface whose exit surface is orthogonal to the reference axis, and its incident surface faces the vehicle rear side. The second lens unit has an optical surface convex toward the front of the vehicle and an incident surface convex toward the rear of the vehicle. It is characterized by being configured as a substantially spherical lens as a whole.

  According to invention of Claim 2, since the 2nd lens part and the light guide part are comprised as another member which isolate | separated physically, each can be manufactured easily. Further, the light guide portion can be made of a material having high heat resistance, and the second lens portion can be made of a transparent resin.

  According to a third aspect of the invention, in the first or second aspect of the invention, the curvature of the exit surface of the second lens portion is smaller than the curvature of the entrance surface of the first lens portion.

  According to the third aspect of the present invention, the projection lens can be configured as a lens from which spherical aberration is removed and which has less aberration that satisfies the Abbe sine condition. As a result, it is possible to form a light distribution pattern for a passing beam having a clear cut-off line that does not generate (or hardly generates) illusion light due to coma aberration or the like above the horizontal line while increasing the far-field illuminance.

  This is because the projection lens is composed of a first lens part and a second lens part (in particular, an exit surface and an entrance surface of the first lens part and an exit surface of the second lens part) instead of a single lens, and This is because the curvature of the exit surface of the second lens unit is made smaller than the curvature of the entrance surface of the first lens unit.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the second lens part and the light guide part are incident on the exit surface of the light guide part and the incident on the second lens part. It is characterized by being configured as an integral lens body in which there is no surface contact with the surface.

  According to the fourth aspect of the present invention, it is possible to eliminate a light amount loss at the interface between the second lens unit and the light guide unit.

  The invention according to claim 5 is the invention according to any one of claims 1 to 5, wherein the light incident on the rear focal plane is incident on the inside of the light guide section, and the lower end surface of the light guide section. After being internally reflected, the light from the light source that reaches the back focal plane and the inside of the light guide unit, and reaches the back focal plane without being internally reflected by the lower end surface of the light guide unit. A light intensity distribution corresponding to the low beam light distribution pattern is formed by the light from the light source, and the light intensity distribution is reversely projected forward by the projection lens, thereby forming the low beam light distribution pattern. It is characterized by that.

  According to the fifth aspect of the present invention, it is possible to form a light distribution pattern for a passing beam including a hot zone (high luminous intensity region) in the vicinity of the horizontal line and having excellent distance visibility.

  ADVANTAGE OF THE INVENTION According to this invention, the light utilization efficiency can improve and the vehicle lamp which can be reduced in size can be provided.

It is a longitudinal cross-sectional view of the vehicle lamp 10 of this embodiment. 1 is a perspective view of a vehicular lamp 10 (lens holder 20 omitted). 3 is an optical path diagram of light from a light source 18. FIG. Example of light distribution pattern P _Lo for passing beam formed on a virtual vertical screen (located about 25 m ahead from the front of the vehicle) facing the front of the vehicle by light emitted forward from the vehicular lamp 10 It is. 3 is a perspective view of a light guide unit 16. FIG. It is the arrow line view (front view) seen from the arrow A direction in FIG. 4 is an enlarged view of the vicinity of an incident surface 16b of the light guide unit 16. FIG. 1 is a perspective view of a vehicular lamp 200 described in Patent Document 1. FIG.

  Hereinafter, a vehicular lamp 10 according to an embodiment of the present invention will be described with reference to the drawings.

1 is a longitudinal sectional view of a vehicular lamp 10 according to the present embodiment, FIG. 2 is a perspective view (lens holder 20 omitted), FIG. 3 is an optical path diagram of light from a light source 18, and FIG. 4 is a front view from the vehicular lamp 10. the light irradiated is an example of directly facing the virtual vertical screen low-beam light distribution pattern P _Lo formed on (located about 25m forward from the vehicle front) to the vehicle front.

As shown in FIGS. 1 and 2, the vehicular lamp 10 according to the present embodiment is arranged in order from the front side of the vehicle toward the rear side of the vehicle, the first lens unit 12, the second lens unit 14, and the light guide unit. 16 and the light source 18, as shown in FIG. 3, after the light from the light source 18 is guided by the light guide unit 16, the light is transmitted through the second lens unit 14 and the first lens unit 12 in this order. As shown in FIG. 4, it is configured as a vehicular lamp that is irradiated and forms a passing beam light distribution pattern P _Lo including a cut-off line CL (CL1 to CL3) at its upper edge.

  As shown in FIG. 1, the first lens portion 12 is a planar optical surface having a front surface 12a (hereinafter referred to as an emission surface 12a) having an infinite radius of curvature, and a rear surface 12b (hereinafter referred to as an incident surface 12b). ) Is configured as a plano-convex lens having a convex optical surface (an optical surface having a negative curvature) toward the vehicle rear side. In the present embodiment, the exit surface 12a of the first lens unit 12 is configured as a planar optical surface orthogonal to a reference axis AX (also referred to as an optical axis) extending in the vehicle front-rear direction, and the first lens The radius of curvature of the incident surface 12b of the portion 12 is set to about 48 mm.

  The first lens unit 12 is held by the lens holder 20 and disposed on the reference axis AX. The lens holder 20 is fixed to the front surface 22a of the heat sink 22 and arranged at the position shown in FIG.

  The second lens portion 14 has a front surface 14a (hereinafter referred to as an emission surface 14a) having a convex optical surface (an optical surface having a positive curvature) toward the vehicle front side, and a rear surface 14b (hereinafter referred to as an incident surface 14b). ) Is configured as a lens portion including a generally spherical lens portion and a flange portion 14c of an optical surface convex toward the vehicle rear side. In the present embodiment, the exit surface 14a of the second lens portion 14 is an optical surface convex toward the front side of the vehicle (an optical surface having a positive curvature) and is optimized to have an aspheric shape that satisfies the following polynomial. ing.

  Each variable in the polynomial used in the present embodiment is as shown in the following table.

  The second lens portion 14 is disposed on the reference axis AX with the flange portion 14c held by the light guide portion 16 in a state where the incident surface 14b is in surface contact with the exit surface 16a of the light guide portion 16. The incident surface 14b of the second lens unit 14 and the output surface 16a of the light guide unit 16 are bonded with a transparent adhesive such as silicon resin. The periphery of the second lens portion 14 is surrounded by a shielding portion 20a provided on the inner peripheral surface of the lens holder 20 for the purpose of covering the internal structure. In addition, the 2nd lens part 14 may be comprised in the shape where the part which does not show | play an optical function was cut.

  The first lens unit 12 and the second lens unit 14 (particularly, the emission surface 12 a and the incident surface 12 b of the first lens unit 12 and the emission surface 14 a of the second lens unit 14) have a focal point F of the emission surface of the light guide unit 16. Projection lens (hereinafter referred to as projection lens 24) located on the interface between 16a and the entrance surface 14b of the second lens unit 14 (for example, near the lower edge 16a1 (stepped edge) of the exit surface 16a of the light guide unit 16) Is configured. The curvature of field (rear focal plane) of the projection lens 24 is the interface between the exit surface 16a of the light guide unit 16 and the entrance surface 14b of the second lens unit 14 (at least the lower edge 16a1 of the exit surface 16a of the light guide unit 16). That is, it substantially coincides with the stepped edge portion).

As described above, the projection lens 24 is not a single lens, but the first lens unit 12 and the second lens unit 14 (in particular, the exit surface 12a and the entrance surface 12b of the first lens unit 12 and the second lens unit 14). By making the exit surface 14a) and the curvature of the exit surface 14a of the second lens unit 14 smaller than the curvature of the entrance surface 12b of the first lens unit 12, the projection lens 24 is free from spherical aberration, In addition, it can be configured as a lens with less aberration that satisfies Abbe's sine condition. As a result, a light distribution pattern for a passing beam having a clear cut-off line CL (CL1 to CL3) in which distant light is not generated (or hardly generated) due to coma aberration or the like above the horizontal line H while increasing the illuminance in the distance. P _Lo can be formed.

  The light guide unit 16 includes an optical surface 16b on the vehicle rear side where light from the light source 18 enters the light guide unit 16 (hereinafter referred to as an incident surface 16b), and light from the light source 18 that enters the light guide unit 16 inside. , And an optical surface 16a (hereinafter referred to as an emission surface 16a) on the vehicle front side. The incident surface 16b is configured as a planar optical surface. In the present embodiment, the incident surface 16b is configured as a planar optical surface perpendicular to the reference axis AX. The exit surface 16a is configured as a concave optical surface toward the vehicle rear side corresponding to the entrance surface 14b of the second lens unit 14 so that the entrance surface 14b of the second lens unit 14 is in surface contact. .

  The light guide unit 16 is fixed to the front surface 22a of the heat sink 22 and is disposed above the reference axis AX. The lower end edge 16a1 of the exit surface 16a of the light guide unit 16 includes a stepped edge portion corresponding to the cut-off line CL (CL1 to CL3), and is disposed in the vicinity of the reference axis AX.

  5 is a perspective view of the light guide unit 16, and FIG. 6 is an arrow view (front view) seen from the direction of arrow A in FIG.

  As shown in FIGS. 5 and 6, the lower end edge 16a1 (stepped edge portion) of the light exit surface 16a of the light guide portion 16 is a side e1 corresponding to the left horizontal cutoff line CL1, and a side corresponding to the right horizontal cutoff line CL2. e2 and a side e3 corresponding to an oblique cut-off line CL3 connecting the left horizontal cut-off line CL1 and the right horizontal cut-off line CL2. The lower end surface 16c of the light guide unit 16 is connected to the lower end edge 16b1 of the incident surface 16b by extending the lower end edge 16a1 (stepped edge portion) of the emission surface 16a to the vehicle rear side along the reference axis AX. It is configured as an optical surface having a different shape. The lower end surface 16c of the light guide part 16 is disposed slightly below the lower end edge (lower long side) of the light emitting surface 18b1 constituting the light source 18 (see FIG. 6).

  The first lens unit 12, the second lens unit 14, and the light guide unit 16 may be made of polycarbonate (PC), or other transparent resins such as acrylic (PMMA), cycloolefin polymer (COP), and silicon resin. It may be made of glass or glass.

  In this embodiment, since the 2nd lens part 14 and the light guide part 16 are comprised as another member which isolate | separated physically, each can be manufactured easily. In addition, the light guide unit 16 can be made of a material having high heat resistance (for example, glass), and the second lens unit 14 can be made of a transparent resin. In addition, since the light guide part 16 is arrange | positioned near the light source 18 which generate | occur | produces heat | fever, it is preferable to make it into a product with high heat resistance.

  As shown in FIG. 6, the light source 18 includes a semiconductor light emitting element 18b such as a white LED light source including a metal substrate 18a and a horizontally long light emitting surface 18b1 (1 × 4 mm in this embodiment). On the surface of the substrate 18a, three semiconductor light emitting elements 18b (in this embodiment, three white LED light sources having a luminous flux of about 1000 lm) are mounted in a line in the horizontal direction to form a horizontally-long rectangular light emitting surface. The semiconductor light emitting element 18b is not limited to a white LED light source, and may be a white LD light source. The number of the semiconductor light emitting elements 18b is not limited to three and can be an appropriate number.

The directivity of light emitted from the light source 18 (light emitting surface 18b1) is Lambertian and can be expressed as I (θ) = I ₀ × cos θ. This represents the spread of light emitted from the light source 18 (light emitting surface 18b1). However, I (θ) represents the luminous intensity in the direction inclined by the angle θ from the optical axis of the light source 18 (light emitting surface 18b1) (extending in the direction perpendicular to the light emitting surface 18b1 through the approximate center of the light emitting surface 18b1). I ₀ represents the luminous intensity on the optical axis of the light source 18 (light emitting surface 18b1). In the light source 18 (light emitting surface 18b1), the luminous intensity on the optical axis (θ = 0) is maximized.

  As shown in FIG. 1, the light source 18 has a light emitting surface 18b1 in the vicinity of the light incident surface 16b of the light guide 16 and the light source 18 facing the light incident surface 16b. It is arranged above the reference axis AX and in the vicinity of the reference axis AX.

  Thus, since the light source 18 (light emitting surface 18b1) is arranged in the state facing the incident surface 16b in the vicinity of the incident surface 16b (its lower edge 16b1) of the light guide unit 16, the light source 18 (light emitting surface 18b1) is separated. Substantially all of the light enters the light guide 16 from the light incident surface 16 b of the light guide 16. The distance between the light source 18 (light emitting surface 18b1) and the incident surface 16b of the light guide unit 16 is preferably smaller from the viewpoint of efficiently making the light from the light source 18 incident, and particularly preferably 1 mm or less. . In this embodiment, the space | interval between the light source 18 (light emission surface 18b1) and the entrance plane 16b of the light guide part 16 is set to about 0.2 mm.

  FIG. 7 is an enlarged view of the vicinity of the incident surface 16b of the light guide unit 16, and represents an optical path of light from the light source 18 (light emitting surface 18b1).

As shown in FIG. 7, the light from the light source 18 (light emitting surface 18b1) that enters the light guide unit 16 is refracted by the incident surface 16b with respect to the optical axis AX ₁₈ of the light source 18 (light emitting surface 18b1). The light is condensed within a range of about 45 degrees, is guided through the light guide 16 toward the emission surface 16a (about 2 mm in this embodiment), and is emitted from the emission surface 16a. A luminous intensity distribution corresponding to the light distribution pattern P _Lo for the passing beam is formed on the exit surface 16a of the light section 16 (that is, on the rear focal plane).

  This luminous intensity distribution is incident on the inside of the light guide unit 16 and is internally reflected (total reflection) at the lower end surface 16c of the light guide unit 16 and then the light from the light source 18 (light emitting surface 18b1) reaching the rear focal plane. It is formed by light from the light source 18 (light emitting surface 18b1) that enters the light guide unit 16 and reaches the rear focal plane without being internally reflected (totally reflected) by the lower end surface 16c of the light guide unit 16. In this light intensity distribution, the area corresponding to the hot zone Z (high light intensity area, see FIG. 4) is brighter than the surrounding area.

  This is because the light source 18 (light-emitting surface 18b1) is disposed in the vicinity of the incident surface 16b (its lower end edge 16b1) of the light guide unit 16 so as to face the incident surface 16b, and the light guide unit 16 is incident. A part of the light from the light source 18 (light emitting surface 18b1) that enters the light guide unit 16 from the surface 16b is internally reflected (total reflection) by the lower end surface 16c of the light guide unit 16, and then on the rear focal plane. By going to the area corresponding to the hot zone Z (see FIG. 4).

  In addition, since the light source 18 (light-emitting surface 18b1) is disposed at a position defocused from the focal point F of the projection lens 24 to the vehicle rear side (about 2 mm in the present embodiment), the light intensity distribution 18 ( The luminance unevenness of the light emitting surface 18b1) hardly appears.

  Further, this luminous intensity distribution includes the sides e1 to e3 corresponding to the cut-off lines CL (CL1 to CL3) since the lower end edge 16a1 of the light exit surface 16a of the light guide unit 16 includes a stepped edge portion. .

By the light intensity distribution is inverted projected forward by the projection lens 24, as shown in FIG. 4, the light distribution pattern P _Lo for low beam including a cut-off line CL (CL1 to CL3) the upper edge is formed. The passing beam light distribution pattern P _Lo is a passing beam light distribution pattern that includes a hot zone Z (high luminous intensity region) in the vicinity of the horizontal line H and has excellent distant visibility.

  As described above, according to the present embodiment, it is possible to provide the vehicular lamp 10 that can improve the light utilization efficiency and can be downsized.

  The light utilization efficiency is improved because the light source 18 (light emitting surface 18b1) is disposed in the vicinity of the incident surface 16b of the light guide 16 in a state of facing the incident surface 16b, and therefore from the light source 18 (light emitting surface 18b1). This is because almost all of the light enters the light guide portion 16 from the incident surface 16b of the light guide portion 16.

  The downsizing is possible because the light utilization efficiency can be improved without using the additional lens described in the prior art (for example, Japanese Patent No. 5196314).

  Next, a modified example will be described.

  In the above embodiment, an example in which the second lens unit 14 and the light guide unit 16 are configured as separate members that are physically separated from each other has been described. However, the present invention is not limited thereto, and the second lens unit 14 and the light guide unit are configured. 16 may be configured as an integral lens body in which there is no portion where the exit surface 16a of the light guide portion 16 and the entrance surface 14b of the second lens portion 14 are in surface contact.

  In this way, it is possible to eliminate a light amount loss at the interface between the second lens unit 14 and the light guide unit 16.

  All the numerical values shown in the above embodiment are examples, and appropriate different numerical values can be used.

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle lamp, 12 ... 1st lens part, 12a ... Front side surface (emission surface), 12b ... Back side surface (incidence surface), 14 ... 2nd lens part, 14a ... Front side surface (emission surface), 14b ... rear side surface (incident surface), 14c ... flange portion, 16 ... light guide portion, 16a ... emitting surface, 16a1 ... lower end edge, 16a2 ... lower end surface, 16b ... incident surface, 18 ... light source, 18a ... substrate, 18b ... Semiconductor light emitting element, 18b1 ... Light emitting surface, 20 ... Lens holder, 20a ... Shielding part, 22 ... Heat sink, 22a ... Front, 24 ... Projection lens

Claims (5)

A first lens unit, a second lens unit, a light guide unit, and a light source arranged in order from the vehicle front side toward the vehicle rear side, and after the light from the light source is guided by the light guide unit In the vehicular lamp, the second lens unit and the first lens unit are transmitted in order and irradiated forward to form a light distribution pattern for a passing beam.
The first lens part and the second lens part are disposed on a reference axis extending in the vehicle front-rear direction,
The light guide unit includes an incident surface on which light from the light source enters the light guide unit, and an output surface on which light from the light source incident on the light guide unit exits, and the reference axis Is located above and
The lower end edge of the exit surface of the light guide part includes a stepped edge part having a shape corresponding to a cut-off line, and is disposed in the vicinity of the reference axis.
The first lens part and the second lens part constitute a projection lens whose focal point is located in the vicinity of the stepped edge part,
The light source includes a horizontally elongated light emitting surface, and the horizontally elongated light emitting surface is disposed above the reference axis and in the vicinity of the reference axis in a state facing the incident surface in the vicinity of the incident surface of the light guide unit,
The exit surface of the light guide unit and the entrance surface of the second lens unit are in surface contact,
The vehicular lamp, wherein a rear focal plane of the projection lens substantially coincides with the stepped edge portion. The first lens portion is configured as a convex lens having a planar optical surface whose exit surface is orthogonal to the reference axis and an optical surface whose incident surface is convex toward the vehicle rear side.
The second lens portion is configured as a substantially spherical lens as a whole, with an optical surface convex toward the vehicle front side and an optical surface convex toward the vehicle rear side. The vehicular lamp according to claim 1.   The vehicular lamp according to claim 1 or 2, wherein the curvature of the exit surface of the second lens portion is smaller than the curvature of the entrance surface of the first lens portion.   The second lens unit and the light guide unit are configured as an integral lens body in which there is no portion where the light exit surface of the light guide unit and the incident surface of the second lens unit are in surface contact with each other. Item 4. The vehicle lamp according to any one of Items 1 to 3. On the rear focal plane, the light from the light source that enters the light guide section and is internally reflected by the lower end surface of the light guide section and then reaches the rear focal plane, and the inside of the light guide section A light intensity distribution corresponding to the light distribution pattern for the low beam is formed by the light from the light source that reaches the rear focal plane without being internally reflected at the lower end surface of the light guide unit,
5. The vehicular lamp according to claim 1, wherein the luminous intensity distribution is reversely projected forward by the projection lens to form the passing beam light distribution pattern. 6.