JP2014175198A - Projector type headlight and projection lens for projector type headlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector type headlight capable of suppressing luminous intensity unevenness appearing in a belt-like light distribution pattern extending to a substantially constant width nearby above a cutoff line along the cutoff line.SOLUTION: A projector type headlight 10 includes a projection lens 14 which is arranged on an optical axis extending in vehicle front/rear directions, a reflecting surface 12a which is arranged behind the projection lens 14, a light source 16 which is arranged behind a rear-side focus of the projection lens 14, and a light shield member 18 which is arranged between the projection lens 14 and light source 16, and cuts off light, traveling upward, of light transmitted through the projection lens 14 to irradiate the front, and is so configured as to form a light distribution pattern including a cutoff line defined by the light shield member 18. At least a part of a surface of the projection lens 14 includes a plurality of concave lens cut surfaces which have perpendicular sectional shapes which are straight lines in contact with a projection reference surface of the surface of the projection lens 14 at both ends and extend in a substantially horizontal direction, and are concave to the projection reference surface.

Description

  The present invention relates to a projector-type headlamp and a projection lens for the projector-type headlamp, and more particularly to a projector-type headlamp configured to form a light distribution pattern including a cut-off line and a projection used therefor Related to lenses.

  Conventionally, in the field of vehicular lamps, a projector-type headlamp configured to form a light distribution pattern including a cut-off line has been proposed (see, for example, Patent Document 1).

  6A is a longitudinal sectional view of the projector-type headlamp 200 described in Patent Document 1, and FIG. 6B is a front view of the vehicle facing the front of the vehicle by light emitted from the projector-type headlamp 200 forward. It is the elements on larger scale of the light distribution pattern P formed on the virtual vertical screen (it is arrange | positioned about 25m ahead from the vehicle front).

  As shown in FIG. 6A, the projector-type headlamp 200 includes a projection lens 210 disposed on an optical axis AX extending in the vehicle front-rear direction, and a rear side focal point F behind the projection lens 210. The light source 220 arranged, the reflector 230 that reflects light from the light source 220 forward and toward the optical axis AX, and the reflected light from the reflector 230 arranged at the rear focal point F of the projection lens 210 And a shade 240 that partially shields the shade.

  In the projector type headlamp 200 having the above-described configuration, from the viewpoint of suppressing the spectral color appearing in the vicinity of the upper part of the cutoff line due to the spectral phenomenon generated when the light from the light source 220 reflected by the reflector 230 passes through the projection lens 210. As shown in FIG. 6B, a strip-shaped light distribution pattern Pa extending at a substantially constant width along the cutoff line CL is formed in the vicinity of the upper side of the cutoff line CL.

  The band-shaped light distribution pattern Pa is formed by light emitted from a plurality of lens elements 212n (concave lens cut surface and convex lens cut surface) formed on the front surface 212 of the projection lens 210.

  Each lens element 212n, as shown in FIG. 7 (a), has a vertical cross-sectional shape of a corrugated shape with respect to the reference surface 212D of the front surface 212, and in a substantially horizontal direction (in FIG. 7 (a)). It is configured as a lens cut surface that is convex and concave with respect to the reference surface 212D, extending in a direction substantially perpendicular to the paper surface.

  The light emitted from a set of lens elements 212n (for example, a total of two lens cut surfaces including a lower concave lens cut surface 212n and an upper convex lens cut surface 212n in FIG. 7A) has one luminous intensity distribution (for example, , The luminous intensity distribution La) in FIG. 7B is formed. As shown in FIG. 7B, this is due to the luminous intensity distribution La1 formed by the emitted light from the lower concave lens cut surface 212n in FIG. 7A and the emitted light from the upper convex lens cut surface 212n. This is because the formed luminous intensity distribution La2 is formed in substantially the same position and in substantially the same shape, and becomes a combined luminous intensity distribution La.

  In FIG. 7A, reference numerals P1 ′, P2 ′, and P3 ′ respectively denote a position near the lower end of the straight line (exit position) that is the vertical cross-sectional shape of the lower concave lens cut surface 212n, and a lower concave lens cut. A position near the upper end of the straight line that is the vertical cross-sectional shape of the surface 212n (exit position), and an intermediate position (exit position) between the straight lines P1 'and P2' that are the vertical cross-sectional shape of the lower concave lens cut surface 212n. ing. Reference numerals P1 ′, P2 ′, and P3 ′ in FIG. 7B denote positions on the luminous intensity distribution La1 formed by the light emitted from the positions P1 ′, P2 ′, and P3 ′ in FIG. Represents.

  Similarly, reference numerals P4 ′, P5 ′, and P6 ′ in FIG. 7A denote a position (exit position) near the lower end of a straight line that is a vertical sectional shape of the upper convex lens cut surface 212n, and an upper convex lens cut surface, respectively. A position near the upper end of a straight line having a vertical cross-sectional shape of 212n (outgoing position), and an intermediate position (outgoing position) between straight lines P4 ′ and P5 ′ of a vertical cross-sectional shape of the upper convex lens cut surface 212n. . Reference numerals P4 ′, P5 ′, and P6 ′ in FIG. 7B denote positions on the luminous intensity distribution La2 formed by the light emitted from the positions P4 ′, P5 ′, and P6 ′ in FIG. Represents.

  As described above, in the projector-type headlamp 200 having the above-described configuration, one luminous intensity distribution is obtained in units of a pair of lens elements 212n (that is, in units of two lens cut surfaces including a concave lens cut surface and a convex lens cut surface). It is meant to be adjusted.

Japanese Patent No. 4597890

  However, in the projector-type headlamp 200 configured as described above, when the luminous intensity distribution in the strip-shaped light distribution pattern Pa is changed in a gradation in the vertical direction, unevenness in luminous intensity occurs in the strip-shaped light distribution pattern Pa. There is.

  For example, as shown in FIG. 8, in the region of the vertical width W in the strip-shaped light distribution pattern Pa, two luminous intensity distributions La and Lb having different peaks and vertical widths are formed, thereby forming the strip-shaped light distribution. When the luminous intensity distribution in the pattern Pa is changed in a gradation in the vertical direction, the luminous intensity distribution in the vertical direction changes sharply (see the oblique straight line L1 (dotted line) in FIG. 8), and the luminous intensity distribution La and luminous intensity distribution Lb This is due to the appearance of a valley V due to the difference in luminous intensity.

  The present invention has been made in view of such circumstances, and in a projector-type headlamp configured to form a light distribution pattern including a cutoff line, along the cutoff line in the vicinity of the upper side of the cutoff line. An object of the present invention is to provide a projector-type headlamp capable of suppressing unevenness in luminous intensity appearing in a strip-shaped light distribution pattern extending at a substantially constant width, and a projection lens used therefor.

  In order to achieve the above object, an invention according to claim 1 is directed to a projection lens disposed on an optical axis extending in a vehicle front-rear direction, a reflecting surface disposed behind the projection lens, and a rear of the projection lens. A light source disposed behind the side focal point, reflected near the optical axis by the reflecting surface, and transmitted through the projection lens to emit light emitted forward; and disposed between the projection lens and the light source A light distribution pattern including a cut-off line defined by the light shielding member, and a light shielding member that blocks upward light among the light from the light source that is transmitted through the projection lens and irradiated forward In the projector-type headlamp configured to form, at least a part of the surface of the projection lens has a vertical cross-sectional shape, and both ends are straight lines in contact with the emission reference plane of the surface of the projection lens, and Extending substantially horizontally, characterized in that it comprises a plurality of concave cut surface concave relative to the exit reference plane.

  According to the first aspect of the present invention, the following advantages are obtained.

  First, in a projector-type headlamp configured to form a light distribution pattern including a cut-off line, the luminous intensity appearing in a band-shaped light distribution pattern extending at a substantially constant width along the cut-off line in the vicinity of the upper part of the cut-off line Unevenness can be suppressed.

  In the first aspect of the present invention, since one luminous intensity distribution can be adjusted in units of one concave lens cut surface, in the vicinity of the upper part of the cut-off line as compared with the prior art (Japanese Patent No. 4597890). In a specific vertical width region in the band-shaped light distribution pattern extending with a substantially constant width along the cut-off line, it is possible to form a light intensity distribution with more peaks (twice the conventional technology) with different peaks and vertical widths. In addition, the luminous intensity distribution can be adjusted so that the luminous intensity distribution in the vertical direction of the band-shaped light distribution pattern changes gradually, and as a result, the influence of the valley that appears due to the luminous intensity difference is suppressed. It is because it is possible.

  Second, it becomes easy to make the cutoff line moderately blurred and to set the sharpness coefficient G value within the target range.

  In the invention described in claim 1 as well, in comparison with the prior art (Japanese Patent No. 4597890), the upper and lower specific distributions in the band-shaped light distribution pattern extending at a substantially constant width along the cutoff line in the vicinity of the upper part of the cutoff line. A light intensity distribution in which the light intensity distribution can be formed more in the width region than in the peak and the vertical width (twice that of the prior art), and the light intensity distribution in the vertical direction of the band-shaped light distribution pattern changes gently. As a result of being able to adjust the respective light intensity distributions so as to satisfy the above, it is possible to suppress the influence of the valley that appears due to the light intensity difference.

  Third, the spectral color that appears due to the spectral phenomenon that occurs when light from the light source reflected by the reflecting surface passes through the projection lens in the vicinity of the upper part of the cutoff line can be made inconspicuous.

  This is because the light emitted forward from the plurality of concave lens cut surfaces formed on the front surface of the projection lens forms a band-shaped light distribution pattern extending substantially along the cutoff line in the vicinity of the upper part of the cutoff line. Is due to

  The present invention can also be specified as the projection lens for a projector type headlamp as follows.

  In the projection lens used for the projector type headlamp, at least a part of the surface of the projection lens has a vertical cross-sectional shape, a straight line whose both ends are in contact with the output reference plane of the surface of the projection lens, and in a substantially horizontal direction. A projection lens for a projector-type headlamp, which extends and includes a plurality of concave lens cut surfaces that are concave with respect to the emission reference surface.

  According to the present invention, in a projector-type headlamp configured to form a light distribution pattern including a cut-off line, a band-shaped light distribution pattern extending at a substantially constant width along the cut-off line in the vicinity of the upper part of the cut-off line. It is possible to provide a projector-type headlamp that can suppress unevenness in luminous intensity that appears, and a projection lens used therefor.

1 is a longitudinal sectional view of a projector-type headlamp 10 that is an embodiment of the present invention. (A) Perspective view of the projection lens 14, (b) Front view, (c) Longitudinal sectional view. (A) Concave lens cut surface 22n formed in the circle in FIG. 2 (c) and a diagram showing the optical path of the emitted light from the concave lens cut surface 22n, (b) Each lens cut shown in FIG. 3 (a) It is an example of luminous intensity distribution LA and LB (AA cross section in FIG. 4) formed with the emitted light from the surface 22n. A partial enlarged view of a light distribution pattern P formed on a virtual vertical screen (disposed approximately 25 m ahead of the front of the vehicle) facing the front of the vehicle by light irradiated forward from the projector-type headlamp 10 It is. It is an example of luminous intensity distribution LA, LB, LC, LD (AA cross section in FIG. 4) formed by the emitted light from each lens cut surface 22n. (A) The longitudinal cross-sectional view of the conventional projector type headlamp 200, (b) It is an example of the light distribution pattern formed with the conventional projector type headlamp 200. FIG. (A) A diagram showing a set of lens elements 212n (concave lens cut surface and convex lens cut surface) formed in a circle in FIG. 6A and an optical path of light emitted from the set of lens elements 212n. b) It is an example (AA cross section in FIG.6 (b)) of luminous intensity distribution La1, La2, La formed by the emitted light from each lens cut surface 212n shown to Fig.7 (a). It is an example of luminous intensity distribution La, Lb formed by the emitted light from each lens cut surface 212n.

  Hereinafter, a projector type headlamp 10 according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a projector type headlamp 10 according to an embodiment of the present invention.

  A projector-type headlamp 10 is a projector-type lamp unit configured to form a low-beam light distribution pattern, and as shown in FIG. 1, is a projection lens arranged on an optical axis AX extending in the vehicle front-rear direction. 14, a reflector 12 including a reflecting surface 12 a disposed behind the projection lens 14, and disposed behind the rear focal point F of the projection lens 14, reflected by the reflecting surface 12 a toward the optical axis AX and projected toward the projection lens 14. A light source 16 that transmits light that passes through the projection lens 14 and emits light emitted forward, and is disposed between the projection lens 14 and the light source 16. The light-shielding member 18 which shields the light which goes to, and the holding member 20 etc. which hold | maintain these are provided.

  The reflecting surface 12a of the reflector 12 is a reflecting surface that reflects light from the light source 16 forward, reflects it toward the optical axis AX, and collects the light near the rear focal point F of the projection lens 14. Specifically, the reflecting surface 12a has an elliptical shape including a first focal point F1 and a second focal point F2 in cross-sectional shape including the optical axis AX, and its eccentricity gradually increases from the vertical cross section toward the horizontal cross section. Is a spheroid reflection surface (such as a spheroid or a free-form surface similar to this). The reflector 12 is fixed to the holding member 20 at the lower end of the periphery.

  The light from the light source 16 reflected by the reflecting surface 12a (vertical cross section) is focused on the second focal point F2 (focal point F of the projection lens 14), then passes through the projection lens 14 and is irradiated forward. On the other hand, the light from the light source 16 reflected by the reflecting surface 12a (horizontal cross section) passes through the projection lens 14 without being condensed at the second focal point F2 (focal point F of the projection lens 14), and the second focal point. It crosses at the front position of F2 (focal point F of the projection lens 14) and is irradiated forward as light that diffuses in the horizontal direction.

  The light source 16 is reflected toward the front by the reflecting surface 12a toward the optical axis AX, enters the projection lens 14 (lens portion 14a) from the rear surface 24 of the projection lens 14 (lens portion 14a), and is on the front surface. A light source that emits light emitted from 22 and irradiated forward is disposed at the first focal point F1 (or the vicinity thereof) of the reflecting surface 12a.

  As the light source 16, for example, a ceramic (or metal) substrate (not shown) and a light source module including a semiconductor light emitting element mounted on the substrate can be used. The semiconductor light emitting element (light source 16) is, for example, a semiconductor light emitting element such as an LED (for example, a light emitting diode including a 1 mm square light emitting surface × 4), and a predetermined interval is provided on the surface of a ceramic (or metal) substrate. It is mounted in a line to form a horizontally long light emitting surface (light emitting part).

  The semiconductor light emitting element (light source 16) may be a semiconductor light emitting element having a structure in which a light emitting color LED (or laser diode) is combined with a yellow fluorescent material (for example, YAG fluorescent material) covering the LED. It may be a semiconductor light emitting device having a structure combining LEDs (or laser diodes) of RGB three colors, or may be a semiconductor light emitting device having another structure. The semiconductor light emitting element (light source 16) may be one or more.

  The light source 16 has a horizontally-long rectangular light emitting surface facing upward, the long side of the horizontally long rectangular light-emitting surface and the optical axis AX are orthogonal (or substantially orthogonal), and the horizontally-long rectangular light emitting surface and the projection lens 14 (lens portion 14a). The substrate on which the semiconductor light emitting element is mounted in a state where the rear focal point F matches (or substantially matches) is fixed to the holding member 20 and is disposed in the vicinity of the optical axis AX.

  As the light source 16, a bulb-type light source such as a discharge bulb or a halogen bulb other than the semiconductor light emitting element may be used.

  The reflection surface 12a has a range from the side of the light source 16 to the upper side (however, from the reflection surface 12a so that light from the light source 16 (horizontal rectangular light emission surface) emitted upward (hemispherical direction) may enter. (Excluding the vehicle front area through which reflected light passes) is covered in a dome shape.

  The holding member 20 includes a mirror surface 18 (light shielding member) extending from the rear focal point F of the projection lens 14 toward the light source 16. The front end edge 18a of the mirror surface 18 is not a straight line but a curved shape according to the spherical aberration of the projection lens 14 from the viewpoint of suppressing the influence of the spherical aberration of the projection lens 14 and making the cutoff line clear. ing.

  The light from the light source 16 incident on the mirror surface 18 is reflected upward, refracted by the projection lens 14 and irradiated below the cutoff line. That is, the light from the light source 16 reflected upward is folded back at the front end edge 18a (cut-off line).

  2A is a perspective view of the projection lens 14, FIG. 2B is a front view, and FIG. 2C is a longitudinal sectional view.

  The projection lens 14 is made of a transparent resin such as acrylic, and includes a lens portion 14a and a flange portion 14b disposed around the lens portion 14a as shown in FIGS. 2 (a) to 2 (c).

  The lens portion 14a is an aspheric lens including a front surface 22 (convex surface), a rear surface 24 (for example, a flat surface), and a rear focal point F on the rear surface 24 side.

  For example, the projection lens 14 (lens portion 14a) is attached to the lens holder 26 in which the flange portion 14b is held by the holding member 20 in a state where the rear focal point F is positioned at the second focal point F2 (or the vicinity thereof) of the reflecting surface 12a. It is fixed and arranged on the optical axis AX.

  As shown in FIG. 2B, the front surface 22 of the projection lens 14 (lens portion 14a) has an upper region 22A, a lower region 22B, and an upper region 22A and a lower region that are vertically separated from the optical axis AX. A central region 22C between 22B is included.

  Each of the upper region 22A and the lower region 22B includes a plurality of concave lens cut surfaces 22n. The central region 22C is configured with a surface shape that remains the reference surface 22D of the front surface 22 of the projection lens 14 (lens portion 14a).

  FIG. 3A shows the concave lens cut surface 22n formed in the circle in FIG. 2C and the optical path of the emitted light from the concave lens cut surface 22n. FIG. 3B is an example of light intensity distributions LA and LB (AA cross section in FIG. 4) formed by the light emitted from each lens cut surface 22n shown in FIG.

  As shown in FIG. 3A, each of the plurality of concave lens cut surfaces 22n has a vertical cross-sectional shape that is a straight line whose both ends are in contact with the output reference surface 22D of the surface 22 of the projection lens 14 (lens portion 14a), and the output It is configured as a concave lens cut surface that is concave with respect to the output reference surface 22D and extends in an arc along the reference surface 22D in a substantially horizontal direction (a direction substantially orthogonal to the middle paper surface in FIG. 3A). Each concave lens cut surface 22n is disposed adjacently in the vertical direction in the upper region 22A and the lower region 22B.

  The lower end of the straight line that is the vertical cross-sectional shape of each concave lens cut surface 22n is continuous with the upper end of the straight line that is the vertical cross-sectional shape of another concave lens cut surface 22n disposed adjacently below the concave lens cut surface 22n. . Similarly, the upper end of the straight line that is the vertical cross-sectional shape of each concave lens cut surface 22n is continuous with the lower end of the straight line that is the vertical cross-sectional shape of another concave lens cut surface 22n disposed adjacent to the concave lens cut surface 22n. doing. As a result, between the concave lens cut surfaces 22n arranged adjacent to each other in the vertical direction, an edge e extending in a substantially horizontal direction (a direction substantially orthogonal to the middle sheet surface in FIG. 3A) is formed.

  Each concave lens cut surface 22n can adjust one luminous intensity distribution in units of one concave lens cut surface 22n. Specifically, one luminous intensity distribution (peak and vertical width) can be adjusted by adjusting the inclination and vertical width (area of the concave lens cut surface 22n) of one concave lens cut surface 22n.

  For example, the luminous intensity distribution LA in FIG. 3B can be formed by adjusting the inclination and vertical width of the concave lens cut surface 22n as in the lower lens cut surface 22n in FIG. . Further, for example, the luminous intensity distribution LB in FIG. 3B can be formed by adjusting the inclination and vertical width of the concave lens cut surface 22n as in the upper lens cut surface 22n in FIG. .

  3A, reference numerals P1, P2, and P3 respectively denote a position (exit position) near the lower end of a straight line that is a vertical sectional shape of the lower concave lens cut surface 22n, and a lower concave lens cut surface 22n. This represents a position (exit position) near the upper end of a straight line having a vertical cross-sectional shape, and an intermediate position (exit position) between the straight lines P1 and P2 being a vertical cross-sectional shape of the lower concave lens cut surface 22n. Reference numerals P1, P2, and P3 in FIG. 3B represent positions on the luminous intensity distribution LA formed by light emitted from the positions P1, P2, and P3 in FIG.

  Similarly, reference numerals P4, P5, and P6 in FIG. 3A denote a position near the lower end of the straight line (outgoing position) that is a vertical sectional shape of the upper concave lens cut surface 22n, and a vertical position of the upper concave lens cut surface 22n, respectively. This represents a position (exit position) near the upper end of a straight line having a cross-sectional shape and an intermediate position (exit position) between P4 and P5 of the straight line being a vertical cross-sectional shape of the upper concave lens cut surface 22n. Symbols P4, P5, and P6 in FIG. 3B represent positions on the luminous intensity distribution LB formed by light emitted from the positions P4, P5, and P6 in FIG.

  Since the projector-type headlamp 10 of the present embodiment is configured to form a low-beam light distribution pattern using a projection lens 14 (convex lens), the light emitted from each position P1 to P6 is directed in the direction of diffusion. .

  FIG. 4 shows a light distribution pattern P formed on a virtual vertical screen (arranged about 25 m ahead from the front of the vehicle) that faces the front of the vehicle by light emitted forward from the projector-type headlamp 10. FIG.

  As shown in FIG. 4, the light distribution pattern P formed by the light irradiated forward from the projector-type headlamp 10 has an upper end at the cut-off line CL defined by the front end edge 18a of the mirror surface 18 (light shielding member). The light distribution pattern is suitable for the low beam light distribution pattern included in the portion. The light distribution pattern P includes a strip-shaped light distribution pattern PA extending in a substantially constant width (for example, a vertical width of about 0.5 °) along the cutoff line CL in the vicinity of the upper side of the cutoff line CL.

  The band-shaped light distribution pattern PA is formed by light emitted from the upper region 22A and the lower region 22B (that is, a plurality of concave lens cut surfaces 22n) formed on the front surface 22 of the projection lens 14 (lens portion 14a). .

  For example, as shown in FIG. 3B, the luminous intensity distribution LA formed by the emitted light from the lower concave lens cut surface 22n in FIG. 3A has a peak in the middle of the vertical direction, and Then, the luminous intensity distribution has a curved shape in which the luminous intensity decreases as it goes up and down from the peak position. Similarly, the luminous intensity distribution LB formed by the emitted light from the upper concave lens cut surface 22n in FIG. 3A has a peak larger than the luminous intensity distribution LA in the middle of the vertical direction, and from the peak position. The light intensity decreases as it goes up and down, and the light intensity distribution is a curved light intensity distribution that is narrower than the light intensity distribution LA.

  The luminous intensity distribution LB has a larger peak than the luminous intensity distribution LA, and the vertical width is narrower than the luminous intensity distribution LA. In order to obtain such a luminous intensity distribution, the inclination and vertical width of each concave lens cut surface 22n (concave lens) This is because the area of the cut surface is adjusted.

  As described above, in the present embodiment, one luminous intensity distribution LA, LB can be adjusted in units of one concave lens cut surface 22n.

  This produces the following advantages.

  For example, by forming a plurality of luminous intensity distributions having different peaks and vertical widths in the region of the vertical width W in the band-shaped light distribution pattern, the luminous intensity distribution in the band-shaped light distribution pattern is changed in a gradation in the vertical direction. In this case, according to the conventional technique (Japanese Patent No. 4597890), N luminous intensity distributions having different peaks and vertical widths (for example, two luminous intensity distributions La and Lb) in the region of the vertical width W in the strip-shaped light distribution pattern Pa. In the present embodiment, in the region of the vertical width W in the band-shaped light distribution pattern PA, N × 2 (that is, twice the conventional technology) having different peaks and vertical widths can be formed. ) (For example, four luminous intensity distributions LA, LB, LC, and LD, see FIG. 5).

  In the prior art (Japanese Patent No. 4597890), N luminous intensity distributions having different peaks and vertical widths (for example, two luminous intensity distributions La and Lb in the region of the vertical width W in the band-shaped light distribution pattern Pa. FIG. (Refer to Fig. 1) can only be formed because the light intensity distribution is adjusted in units of a pair of lens cut surfaces (that is, a unit of two lens cut surfaces including a concave lens cut surface and a convex lens cut surface). is there.

  In this embodiment, in the region of the vertical width W in the strip-shaped light distribution pattern PA, N × 2 (that is, twice the conventional technology) luminous intensity distributions (for example, four luminous intensity distributions LA) having different peaks and vertical widths. , LB, LC, and LD (see FIG. 5) can be formed because the light intensity distribution is adjusted in units of one concave lens cut surface 22n.

  As a result, in this embodiment, as shown in FIG. 5, the luminous intensity distribution in which the luminous intensity distribution in the vertical direction changes gently (see an oblique straight line (dotted line) in FIG. 5), and the valley that appears due to the luminous intensity difference The influence can be suppressed.

  In FIG. 5, the light intensity distributions LA to LD change in a gradation shape so that each concave lens cut surface 22n has an inclination and a vertical width (the concave lens cut surface of the concave lens cut surface). This is because the area is adjusted.

  As described above, according to the projector type headlamp 10 of the present embodiment, the following advantages are produced.

  First, in the projector-type headlamp 10 configured to form the light distribution pattern P including the cut-off line CL, a strip-shaped distribution extending at a substantially constant width along the cut-off line CL in the vicinity of the upper part of the cut-off line CL. Luminance unevenness appearing in the light pattern PA can be suppressed.

  In this embodiment, since one luminous intensity distribution LA and the like can be adjusted in units of one concave lens cut surface 22n in this embodiment, in the vicinity of the upper part of the cut-off line CL compared to the prior art (Japanese Patent No. 4597890). In a specific vertical region W (see FIG. 5) in the band-shaped light distribution pattern PA extending at a substantially constant width along the cut-off line CL, the peak and the vertical width are different (twice that of the prior art). Distributions (see, for example, the luminous intensity distributions LA to LD in FIG. 5), and the luminous intensity distributions so that the luminous intensity distributions in the vertical direction of the strip-shaped light distribution pattern PA are gradually changed. As a result of adjusting the distribution LA or the like, it is possible to suppress the influence of the valley that appears due to the difference in luminous intensity.

  Second, it becomes easy to make the cutoff line CL moderately blurred and to set the sharpness coefficient G value within the target range.

  Also in this embodiment, compared with the prior art (Japanese Patent No. 4597890), a specific vertical width in the strip-shaped light distribution pattern PA extending at a substantially constant width along the cutoff line CL in the vicinity above the cutoff line CL. In the region W of FIG. 5 (see FIG. 5), it is possible to form a light intensity distribution (for example, the light intensity distributions LA to LD in FIG. The light intensity distribution LA can be adjusted so that the light intensity distribution in the vertical direction of the band-shaped light distribution pattern PA changes gradually, thereby suppressing the influence of the valley that appears due to the light intensity difference. Is due to what can be done.

  The sharpness coefficient G value is the sharpness coefficient of light on the cut-off line, and the lower the value, the more blurred it is (in contrast, the higher the value, the clearer it is). The G value is obtained by the following formula.

G value = (logEβ-logE (β-0.1 °))
Here, E represents the luminous intensity [unit, cd], and β represents the vertical angular position [unit, °] (AA cross-sectional direction angle). The target range of the G value is represented by minimum definition (for example, 0.13) ≦ G value ≦ maximum definition (for example, 0.40). However, the minimum sharpness and the maximum sharpness differ depending on the applicable regulations for headlamps.

  In the prior art (Japanese Patent No. 4597890), as shown in FIG. 8, the light / dark difference becomes strong due to the influence of the valley V caused by the light intensity difference between the light intensity distribution La and the light intensity distribution Lb (= the light / dark difference is clear). The G value becomes 0.40 or more, and it is difficult to make the G value within the target range.

  Third, the spectral color that appears due to the spectral phenomenon that occurs when the light from the light source 16 reflected by the reflector 12 passes through the projection lens 14 in the vicinity of the upper part of the cutoff line CL can be made inconspicuous.

  This is a belt-like shape extending with a substantially constant width along the cut-off line CL in the vicinity of the upper part of the cut-off line CL by light emitted forward from the upper region 22A and the lower region 22B formed on the front surface 22 of the projection lens 14. This is because the light distribution pattern PA is formed.

  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 ... Projector type headlamp, 12 ... Reflector, 12a ... Reflecting surface, 14 ... Projection lens, 16 ... Light source, 18 ... Light-shielding member, 20 ... Holding member, 22 ... Front side surface, 24 ... Rear side surface, 26 ... Lens holder

Claims (2)

A projection lens disposed on an optical axis extending in a longitudinal direction of the vehicle, a reflection surface disposed behind the projection lens, and disposed behind a rear focal point of the projection lens; A light source that is reflected on the projection lens and emits light that irradiates forward through the projection lens; and the light source that is disposed between the projection lens and the light source and that is transmitted forward through the projection lens A projector-type headlamp configured to form a light distribution pattern including a cut-off line defined by the light-shielding member.
At least a part of the surface of the projection lens has a vertical cross-sectional shape, both ends of which are straight lines in contact with the output reference surface of the surface of the projection lens, extend in a substantially horizontal direction, and are concave with respect to the output reference surface. A projector-type headlamp comprising a plurality of concave lens cut surfaces. In projection lenses used for projector-type headlamps,
At least a part of the surface of the projection lens has a vertical cross-sectional shape, both ends of which are straight lines in contact with the output reference surface of the surface of the projection lens, extend in a substantially horizontal direction, and are concave with respect to the output reference surface. A projection lens for a projector-type headlamp, comprising a plurality of concave lens cut surfaces.