WO2011078008A1

WO2011078008A1 - Vehicle headlight

Info

Publication number: WO2011078008A1
Application number: PCT/JP2010/072449
Authority: WO
Inventors: 大輔棚橋
Original assignee: コニカミノルタオプト株式会社
Priority date: 2009-12-24
Filing date: 2010-12-14
Publication date: 2011-06-30
Also published as: JPWO2011078008A1

Abstract

Disclosed is a vehicle headlight that can be made more compact and that is also highly efficient and has excellent cutoff properties. The vehicle headlight (100) is provided with a surface-emitting light source (2), a first reflecting mirror (1), and a lens (3); uses the z-axis facing the direction of vehicle progression; uses the position of the vertex of the first reflecting mirror (1) that has curvature as the coordinate origin (P) and has the light source (2) disposed within the yz plane on the center of curvature of the first reflecting mirror (1) when the horizontal direction intersecting the z-axis is the x-axis and the vertical direction is the y-axis; and fulfills formula (1) when the focal point on the light source (2) side of the first reflecting mirror (1) that is closest to the vertex from the position of the origin (P) is a first focal point, another focal point is a second focal point, the distance from the position of the origin (P) to the position of the first focal point is F1, the distance from the position of the origin (P) to the position of the second focal point is F2, and the distance from the position of the origin (P) to the position of a focal point on the reverse side of the lens (3) in the z-axis direction is F. Formula (1) |F-F1| ≦ |F2|(mm)

Description

Vehicle headlamp

The present invention relates to a vehicle headlamp.

In recent years, small and lightweight headlights have been desired from the viewpoint of environmental considerations, and white LEDs are expected to be used as the light source of the headlights.

Sufficient brightness is one of the performance requirements for headlights. This is an essential requirement for the basic performance of headlights. In order to achieve sufficient luminance, an approach from two directions is required to increase the efficiency of the optical system and increase the amount of light of the light source itself.

The former approach is to improve the light utilization efficiency by devising the configuration of the optical system. However, if the optical system is downsized, it becomes difficult to maintain the efficiency of the optical system, and therefore it is essential to increase the light quantity of the light source. Therefore, it is necessary to increase the amount of light of the latter approach, that is, the light source itself, but there is a limit to increasing the amount of light with a single LED chip, and it is difficult to secure necessary power. The form of using is generally used.

As described above, in a headlight optical system using LEDs as a light source, it is required to reduce the size of the optical system, and it is necessary to use a plurality of LED chips. The area must be relatively large. This means that the light source cannot be regarded as a point light source, and in considering the configuration of the optical system, it is necessary to consider the spatial expansion of the light emission position.

Conventionally, as an optical system for a headlight, an optical system composed of an elliptical reflecting mirror and a projection lens is known (see, for example, Patent Documents 1 to 3). In this case, the light is condensed on the ellipsoidal surface of the ellipsoidal reflector, and light that is substantially parallel to the front of the vehicle is emitted by the projection lens. When the light source is a point light source, perfect parallel light can be emitted by adjusting the parameters of the ellipsoid and the projection lens. However, in such an optical system, when the area of the light source becomes relatively large with respect to the size of the optical system, all the light cannot be emitted as parallel light, and the length in the depth direction (vehicle traveling direction) is long. There is a problem that shortening is difficult.

In addition, as an optical system for headlights, a configuration using an elliptical reflecting mirror and a parabolic reflecting mirror in combination is known (for example, see Patent Document 4). In this case, a light source is arranged at the first focal point of the elliptical surface of the elliptical reflector, basically the second focal point of the elliptical surface and the focal point of the paraboloid are approximately matched, and the light is condensed by the elliptical surface of the elliptical reflective mirror. Instead of a projection lens, parallel light is emitted on a parabolic surface. According to such a structure, when a point light source is used, the light reflected by the ellipsoid can be made into parallel light. Moreover, in patent document 4, according to optical paths, such as an optical path reflected from an ellipsoid and then reflected by a paraboloid, or an optical path directly incident on a paraboloid, the paraboloid is divided to make each region an optimal shape. By setting, it is set as the structure which can make all the emitted light into a substantially parallel light. These configurations have an advantage that the size in the vehicle traveling direction can be shortened because the optical path is bent compared to an optical system including an elliptical reflecting mirror and a projection lens.

JP 2005-209604 A JP 2008-77890 A JP 2009-199938 A JP 2007-123027 A

However, the configuration of the conventional example is a configuration that provides the best performance when the light source can be regarded as a point light source. Therefore, when the optical system is downsized and the light source is relatively large, or when the light source has a certain size, there is a problem that sufficient performance cannot be obtained with the conventional configuration described above. It was. Specifically, the influence of the spread of the light emission position differs depending on the horizontal direction (left-right direction and front-back direction) with respect to the ground, so that sufficient performance can be obtained when the light source area becomes larger than the optical system. It was difficult.

The present invention has been made in view of the above circumstances, and in a headlight optical system using a white LED as a light source, it is possible to reduce the size, particularly the front and rear sizes, even though the reflecting surface is smooth and not divided. The purpose of the present invention is to provide a vehicular headlamp that can be made compact with high efficiency and excellent cut-off characteristics.

According to one aspect of the invention, a surface emitting light source;
A first reflector;
A lens, and
Taking the z-axis toward the vehicle traveling direction, the horizontal direction orthogonal to the x-axis and the vertical direction as the y-axis, the vertex position of the first reflecting mirror having the curvature is taken as the origin of coordinates,
In the yz plane,
The light source is provided on the curvature center side of the first reflecting mirror;
The focal point closest to the vertex on the light source side of the first reflecting mirror from the origin position of the coordinates is the first focal point, and the other focal point is the second focal point,
The distance from the origin position of the coordinates to the position of the first focus is F1,
The distance from the origin position of the coordinates to the position of the second focus is F2,
Provided is a vehicular headlamp that satisfies the following expression (1), where F is the distance from the coordinate origin position to the focal position on the rear side in the Z-axis direction of the lens.

| F-F1 | ≦ | F2 | (mm) ... Formula (1)

According to the present invention, it is possible to obtain an illumination distribution with high efficiency, compactness, and excellent cut-off characteristics.

It is a schematic side view when the vehicle headlamp in the present embodiment is viewed from the side. It is a schematic diagram of the vehicle headlamp shown in FIG. It is the perspective view which showed the specific example of the lens. (A) is the side view which showed the light ray at the time of arrange | positioning the light-shielding member, (b) is the front view at the time of seeing from the front. (A) is the figure which showed the light ray when not arrange | positioning an auxiliary reflecting mirror, (b) is the figure which showed the light ray when the auxiliary reflecting mirror is arrange | positioned. It is a schematic diagram for demonstrating the term at the time of prescribing | regulating the efficiency of an optical system. It is the schematic diagram which showed the arrangement | positioning relationship between the vehicle headlamp and screen at the time of obtaining the illumination intensity distribution of emitted light, (a) is a top view, (b) is a front view when it sees from a vehicle advancing direction. is there. It is an illumination intensity distribution of the emitted light of Example 1. FIG. It is an illumination intensity distribution of the emitted light of Example 2. It is an illumination intensity distribution of the emitted light of Example 3. It is an illumination intensity distribution of the emitted light of Example 4. It is an illuminance distribution of the emitted light of Example 5. It is an illumination intensity distribution of the emitted light of Example 6. 10 is an illuminance distribution of emitted light in Example 7. It is an illuminance distribution of the emitted light of Example 8. It is an illuminance distribution of the emitted light of Example 9. It is an illumination intensity distribution of the emitted light of Example 10. It is an illumination intensity distribution of the emitted light of Example 11. It is an illuminance distribution of the emitted light of Example 12. It is an illuminance distribution of the emitted light of Example 13. It is an illuminance distribution of the emitted light of Example 14. It is an illumination intensity distribution of the emitted light of the comparative example 1. It is an illumination intensity distribution of the emitted light of the comparative example 2. It is an illumination intensity distribution of the emitted light of the comparative example 3. It is an illumination intensity distribution of the emitted light of the comparative example 4.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view of the vehicle headlamp according to the present embodiment as viewed from the side, and FIG. 2 is a schematic diagram of the vehicle headlamp shown in FIG.

In the figure, the x-axis direction is perpendicular to the traveling direction of the vehicle and horizontal to the ground (left-right direction), the y-axis direction is perpendicular to the ground (up-down direction), and the z-axis direction is the traveling direction of the vehicle. The horizontal direction.

As shown in FIGS. 1 and 2, the vehicle headlamp 100 includes a light source 2, a first reflecting mirror 1, and a lens 3.

The light source 2 emits light and is formed in a flat plate shape, for example. Here, the surface emission means that the area of the light emitting surface is 0.25 mm ² or more. The area of the light emitting surface is a rectangular area formed by a line parallel to the x axis and a line parallel to the z axis so as to surround the light emitting area of the light source 2. The area of the light emitting surface in the case of having a plurality of light sources 2 is a rectangular shape formed by a line parallel to the x axis and a line parallel to the z axis that is in contact with the light emitting region located at the outermost part so as to surround the plurality of light sources. The area. Examples of such a light source 2 include a semiconductor light emitting device such as a white LED or an organic EL device.

The light emitting surface of the light source 2 (upper surface in FIG. 2) faces the positive direction of the y-axis, and the area S of the light emitting surface of the light source 2 (upper surface in FIG. 2) is the vehicle traveling direction (z When the length in the axial direction) is L and the length in the horizontal direction (x-axis direction) orthogonal to the length is M, it can be expressed as S = M × L, and it is preferable to satisfy the following formula (4).

L ≦ 3 (mm) Expression (4)
The above expression (4) is a conditional expression in which the size of the light source 2 in the vehicle traveling direction is limited. By using the surface-emitting light source 2 that fits within the conditional expression (4), high efficiency, compactness and cut can be achieved. This is effective for obtaining an illuminance distribution with excellent off characteristics.

In FIG. 2, the light emitting surface of the light source 2 is arranged so as to be parallel to the x-axis and the z-axis, but if it is within a range of 20 ° or less with respect to the plane composed of the x-axis and the z-axis. It may be tilted. In this case, L is the length in the z-axis direction of the light emitting surface viewed from the y-axis direction.

The light source 2 is specifically composed of a plurality of LED chips and a phosphor layer formed on the LED chips (not shown). The LED chip emits light having a first predetermined wavelength. In the present embodiment, the LED chip emits blue light. However, the wavelength of the LED chip of the present invention and the wavelength of the emitted light from the phosphor are not limited, and the wavelength of the emitted light from the LED chip and the wavelength of the emitted light from the phosphor are in a complementary color relationship and the synthesized light is white. Any combination that provides light can be used.

In addition, as such an LED chip, a well-known blue LED chip can be used. As the blue LED chip, any existing one including In _x Ga _1-x N system can be used. The emission peak wavelength of the blue LED chip is preferably 440 to 480 nm. In addition, as a form of the LED chip, the LED chip is mounted on the substrate and directly radiated upward or sideward, or the blue LED chip is mounted on a transparent substrate such as a sapphire substrate, and bumps are formed on the surface thereof. Any form of LED chip, such as a so-called flip chip connection type, in which it is formed and turned over and connected to an electrode on a substrate, can be applied.

The phosphor layer has a phosphor that converts light having a first predetermined wavelength emitted from the LED chip into a second predetermined wavelength. In the present embodiment, blue light emitted from the LED chip is converted into yellow light.

The phosphor used for such a phosphor layer uses an oxide or a compound that easily becomes an oxide at a high temperature as a raw material of Y, Gd, Ce, Sm, Al, La and Ga, and converts them into a stoichiometric amount. The raw material is obtained by thoroughly mixing in a theoretical ratio. Alternatively, a coprecipitated oxide obtained by calcining a solution obtained by coprecipitation of oxalic acid with a solution obtained by dissolving a rare earth element of Y, Gd, Ce, and Sm in an acid at a stoichiometric ratio, and aluminum oxide and gallium oxide. Mix to obtain a mixed raw material. An appropriate amount of fluoride such as ammonium fluoride is mixed with this as a flux and pressed to obtain a molded body. The compact can be packed in a crucible and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a sintered body having the phosphor emission characteristics.

In the following description, a case where the first reflecting mirror is configured with an ellipse-based surface will be described as an example.

The first reflecting mirror 1 has a substantially semi-elliptical shape having a curvature obtained by vertically cutting an elliptical sphere having a hollow inside along a plane including the short axis 1b. However, when forming the first reflecting mirror 1, it is not necessary to cut and shape as described above, and the metal is directly shaped so that the surface shape is substantially a semi-elliptical sphere required by the first reflecting mirror 1. Alternatively, a reflecting mirror may be formed by forming a reflective surface by forming a metal reflective layer on the surface by vapor deposition or the like after molding glass or a resin substrate. The reflecting surface of the inner surface 13 (the surface facing the light source 2) of the first reflecting mirror 1 can be made of a metal such as Al or Ag or a metal film, which can easily obtain a high reflectance in a wide wavelength range. Preferably it is. The reflecting surface is preferably made of a material that hardly deteriorates against heat or light from the LED chip.

In such a first reflecting mirror 1, the cut surface 11 having a shape obtained by cutting an elliptical sphere along the short axis 1b direction faces the front in the vehicle traveling direction.

The first reflector may have an anamorphic surface.

The lens 3 is an anamorphic optical system that is provided in front of the first reflecting mirror 1 with respect to the vehicle traveling direction and has different power in the horizontal direction (x-axis direction) and the vertical direction (y-axis direction). Is desirable. As a result, it is possible to obtain an illuminance distribution having an angular distribution that is wide in the x-axis direction and narrow in the y-axis direction. The lens may be a free-form surface such as an xy polynomial, or may have a surface shape that is asymmetric left and right (x-axis direction) across the optical axis (z-axis direction). Further, it may have a surface shape that is asymmetric in the vertical direction (y-axis direction), and is more preferably an optical system having an asymmetric surface shape in all directions. An example of such an anamorphic optical system is shown in FIGS.

Further, when the apex position of the first reflecting mirror 1 is the origin P of the coordinates, the lens 3 is preferably decentered such as shifting in the y-axis direction or tilting around the x-axis with respect to the z-axis. By decentering in this way, the amount of light can be used effectively, and parallel light can be obtained. The first reflecting mirror 1 or the light source 2 is not limited to the lens 3 and may be decentered.

As shown in FIG. 2, the vertex position of the first reflecting mirror 1 is taken as the origin P of the coordinates, and the light source 2 is arranged on the curvature center side of the first reflecting mirror 1 in the yz plane. The focal point closest to the vertex on the light source 2 side of the first reflecting mirror 1 from the coordinate origin position P is the first focal point (Mf1), the other focal point is the second focal point (Mf2), and from the coordinate origin position P. The distance to the first focal position is F1, the distance from the coordinate origin position P to the second focal position is F2, the rear position (light source side) focal position of the lens 3 from the coordinate origin position P in the vehicle traveling direction z (Lf) ), The following formula (1) is satisfied.

| F−F1 | ≦ | F2 | (mm) (1)
The values of F, F1, F2, and Fb below are all values in the yz section. Further, when the first reflecting mirror does not include a vertex, the vertex of the first reflecting mirror is a point where a perpendicular line drawn from an end point closest to the light source of the first reflecting mirror to a plane including the light emitting surface of the light source 2 intersects. And

The first focus and the second focus are present when the first reflecting mirror is a surface or hyperboloid surface based on an ellipse. For example, in the case of a spherical surface or a paraboloid, the second focus does not exist. , Second focus = first focus.

Thus, by satisfying the formula (1), it is possible to obtain a highly efficient, compact and illuminance distribution with excellent cut-off characteristics. More desirably, | F−F1 | ≦ | (F1 + F2) / 2 |. If the conditional expression (1) is not satisfied, the efficiency of the optical system is lowered. If the condition | F | = | F2 | as in the prior art, the amount of light entering the lens 3 is reduced when the light source 2 is finite, and as a result, the efficiency of the optical system is lowered.

Further, when the length from the focal position Lf on the rear side (light source side) of the lens 3 in the vehicle traveling direction z to the first surface S2 (front surface in the vehicle traveling direction) of the lens 3 is Fb, the following formula (2 ) Is preferably satisfied.

| F−F1 | ≦ | Fb | (mm) (2)
The above equation (2) is an equation that defines the positional relationship between the first reflecting mirror (position of the light source 2) 1 and the lens 3. If this condition is satisfied, the optical system is efficient, compact, and excellent in cutoff characteristics. It can be set as this structure. If this conditional expression (2) is deviated, the light flux entering the lens 3 decreases, and even if light enters the lens, the light flux does not exit forward, or total reflection occurs inside the lens and exits backward. The efficiency of the optical system is reduced. By satisfying the above formulas (1) and (2) at the same time, a synergistic effect can be expected.

Furthermore, it is preferable that F and F2 satisfy the following formula (3).

| F | <| F2 | ... Formula (3)
The above expression (3) is a relational expression between the focal position of the lens 3 and the second focal position of the first reflecting mirror 1, and a compact optical system can be obtained by satisfying this expression (3).

Moreover, it is preferable to satisfy | fill following formula (5).
(Shortest distance between the center of the light emitting surface of the light source and the first focal point of the first reflecting mirror) ² <Light emitting area: Formula (5)
The above formula (5) is a relational expression between the center position of the light emitting surface and the focal position of the first reflecting mirror 1 in the z-axis direction. By satisfying this relational expression, the illuminance distribution can be controlled more arbitrarily. Is possible. The center of the light emitting surface is the center position of the surface emitting light source 2. For example, when there are a plurality of surface emitting light sources 2, the entire surface emitting light sources 2 are parallel to the x axis and the z axis, respectively. The center of the rectangle enclosed by.

Further, when the distance from the coordinate origin position P to the first surface S2 of the lens 3 is Ls, it is preferable to satisfy the following formula (6).

Ls ≧ F2 Formula (6)
By satisfying the above formula (6), a compact and efficient optical system can be obtained.

FIG. 4 shows a case where a light shielding member is arranged in order to obtain better cut-off characteristics.

Generally, light distribution with a suitable cut-off line is required on the oncoming vehicle side, and light distribution without a cut-off line is required on the pedestrian side to check pedestrians and signs. Is needed. In order to satisfy this, it is preferable to provide a light shielding member as shown in FIG. When the vertex position of the first reflecting mirror 1 is the origin of coordinates, the light shielding member 4 shields one side in the left-right direction (x-axis direction) across the z axis inside the first reflecting mirror 1. (See FIG. 4B) It is preferable to arrange. By using the light shielding member 4 as shown in FIG. 4B, the cut-off characteristic in the left-right direction can be changed, and a good cut-off characteristic can be obtained.

FIG. 5A shows a case where no auxiliary reflecting mirror is arranged, and FIG. 5B shows a case where an auxiliary reflecting mirror is arranged.

As shown in FIG. 5B, it is preferable to dispose the auxiliary reflecting mirror 5 between the first reflecting mirror 1 and the lens 3 in the vehicle traveling direction and below the first reflecting mirror 1 in the vertical direction. . For example, it is preferable that the auxiliary reflecting mirror 5 has a substantially planar shape and is inclined with respect to the vehicle traveling direction so that the rear end portion is downward with respect to the front end portion. Such an auxiliary reflecting mirror 5 makes it possible to obtain a desired illuminance distribution. The auxiliary reflecting mirror 5 may be a plane mirror or a mirror such as a cylinder pipe.

As described above, the light source 2, the first reflecting mirror 1, and the lens 3 are configured, and by satisfying the above formula (1), the distance between the first reflecting mirror 1 and the lens 3 can be reduced. As a result, when the light source 2 is a surface light source instead of a point light source, the light source 2 can be made compact as compared with the conventional optical system, and an illuminance distribution with high efficiency and excellent cut-off characteristics can be obtained.

In addition, by using the hyperboloid shape for the first reflecting mirror, the angle difference between the maximum luminous intensity region and the luminous intensity 0 region is small, that is, the gradient angle of the luminous intensity distribution from the maximum luminous intensity to the luminous intensity 0 is excellent. A headlight optical system having cut-off characteristics can be provided.

That is, F1 <| S0-P | and F <0.

At this time, the value of F2 takes the range of F2 <F (absolute value | F | <| F2 |).

Note that the hyperboloid shape referred to here is the shape in the y direction when X = 0. In other words, a biconic surface having a different curvature and shape in the x direction may be used, or an asymmetric xy polynomial surface may be used.

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples.

As shown in Tables 1 and 2 below, a light source is irradiated using vehicle headlamps (Examples 1 to 14 and Comparative Examples 1 to 4) designed so that each parameter has a predetermined value. Table 3 below shows the results of simulation of performance in the case of the above. At this time, the following design performance was evaluated in each example and comparative example. In Tables 1 and 2, d represents the axial thickness of the projection lens.

In general, a rotationally symmetric polynomial aspherical expression about the optical axis z can be expressed as follows.

Z is the sag amount of curvature, y is the height from the optical axis, R is the radius of curvature in the yz plane, and κ is the conic coefficient.

Further, generally, if the directions orthogonal to the optical axis z are x and y, the descriptive formula of the biconic surface can be expressed as follows.

Here, Rx: radius of curvature in x direction, Ry: radius of curvature in y direction, κ _x : conic coefficient in x direction, and κ _y : conic coefficient in y direction.

Xy polynomial surface equation can be expressed as follows.

Here, N is the number of polynomial coefficients, and A _i is the coefficient of the i-th term.

For the lenses used in the respective examples, Examples 3 and 5 are polynomial aspheric surfaces, Examples 4, 7, and 11 to 14 are biconic surfaces, and Example 6 is an xy polynomial surface. Further, Example 5 uses the light shielding plate shown in FIG.

[Miniaturization]
As a measure for miniaturization, the ratio R of the volume occupied by the optical system to the area of the light emitting surface was used, and the value of R was obtained for each of the examples and comparative examples. R was calculated as follows, and the results are shown in Table 4.

R = V / S [mm]
S: Area of light emitting surface [mm ² ]
V: volume of the optical system [mm ³ ] (the volume of the optical system is the maximum horizontal length of the light passage region in the optical system through which the light emitted from the light source passes before exiting the optical system × vertical direction Maximum length x maximum length in the vehicle traveling direction)
In the vehicle headlamp using the current white LED, S = 3 [mm ² ], V = 12,000,000 [mm ³ ] (maximum horizontal length: 200 [mm], vertical maximum length: 60 [Mm], the maximum length in the vehicle traveling direction: 100 [mm]) is typical, and R = 400000 [mm]. In the present invention, the case of R <62500, which is 1 / 6.4, is defined as a small optical system. For S = 4 [mm ² ], V <250,000 [mm ³ ] (horizontal maximum length: 100 [mm], vertical maximum length: 50 [mm], vehicle traveling direction maximum) It corresponds to the length [50 mm].

[High performance]
About the point that it is high performance, although it is a small optical system with respect to the light emission area of a white LED light source, the value of (eta) was calculated | required about each Example and the comparative example using the following scale (eta). η was calculated as follows, and the results are shown in Table 3. In order to satisfy the generally required performance, it is preferable that η> 1.0E ⁻⁵ (E ⁻⁵ represents 10 ⁻⁵ ).

η = optical system efficiency / R
Optical system efficiency = forward outgoing light [Lumen] / outgoing light from the light source [Lumen]
Forward: Within ± 25 ° in the horizontal direction from the vehicle traveling direction and within −10 ° to 10 ° in the vertical direction (see FIG. 6).

From the results of Table 4, it can be seen that Examples 1 to 14 can achieve both miniaturization and high performance as compared with Comparative Examples 1 to 4.

Further, as shown in FIGS. 7 (a) and 7 (b), in a position 10m away from the vehicle headlamps of Examples 1 to 14 and Comparative Examples 1 to 4, the road surface is perpendicular to the road surface. A virtual screen was provided so that the simulation was performed when the vehicle headlight was used for irradiation. The simulation was performed assuming a Lambertian LED as the light source. Illuminance distribution [lx] of the emitted light at this time is shown in FIGS. 8 to 24, the horizontal axis represents the horizontal distance [mm], and the vertical axis represents the vertical distance [mm]. Note that the illuminance distribution in the figure is a case where one vehicle headlamp is used.

Conditions with good illuminance distribution (conditions of the embodiment) are (i) a 400 lumin light source, (ii) the strongest central illuminance of 100 lx or more on the screen 10 m ahead from the light source position, and (iii) no multiple hot spots (There are no two or more places with the strongest illuminance), and (iv) it does not spread out in the y-axis direction.

8 to 24, it can be seen that Examples 1 to 14 clearly have superior illuminance distribution and higher performance than Comparative Examples 1 to 4.

DESCRIPTION OF SYMBOLS 1 1st reflective mirror 2 Light source 3 Lens 4 Light-shielding member 5 Reflector 100 Vehicle headlamp Mf1 1st focus of 1st reflective mirror Mf2 2nd focus of 1st reflective mirror Lf Focus of lens

Claims

A surface emitting light source;
A first reflector;
A lens, and
Taking the z-axis toward the vehicle traveling direction, the horizontal direction orthogonal to the x-axis and the vertical direction as the y-axis, the vertex position of the first reflecting mirror having the curvature is taken as the origin of coordinates,
In the yz plane,
The light source is provided on the curvature center side of the first reflecting mirror;
The focal point closest to the vertex on the light source side of the first reflecting mirror from the origin position of the coordinates is the first focal point, and the other focal point is the second focal point,
The distance from the origin position of the coordinates to the position of the first focus is F1,
The distance from the origin position of the coordinates to the position of the second focus is F2,
A vehicle headlamp characterized by satisfying the following formula (1), where F is a distance from a coordinate origin position to a focal position on the rear side in the z-axis direction of the lens.
| F−F1 | ≦ | F2 | (mm) (1)
2. The vehicle headlamp according to claim 1, wherein the length from the focal position of the lens to the first front surface of the lens in the vehicle traveling direction is Fb, and the following formula (2) is satisfied. .
| F−F1 | ≦ | Fb | (mm) (2)
The vehicle headlamp according to claim 1 or 2, wherein the following formula (3) is satisfied.
| F | <| F2 | ... Formula (3)
4. The vehicle headlamp according to claim 1, wherein one or both of the first reflecting mirror and the lens have different powers in the x-axis direction and the y-axis direction.
The vehicle headlamp according to any one of claims 1 to 4, wherein when a length of the light emitting surface of the light source in the z-axis direction is L, the following formula (4) is satisfied.
L ≦ 3 (mm) Expression (4)
The vehicle headlamp according to any one of claims 1 to 5, wherein a light-shielding member is disposed between the first reflecting mirror and the lens in the vehicle traveling direction.
The vehicle headlamp according to any one of claims 1 to 6, wherein a reflector is disposed between the first reflector and the lens in the vehicle traveling direction.
The vehicle headlamp according to any one of claims 1 to 7, wherein the following formula (5) is satisfied.
(Shortest distance between the center of the light emitting surface of the light source and the first focal point of the first reflecting mirror) 2 <Light emitting area: Formula (5)
The vehicle headlamp according to any one of claims 1 to 8, wherein the light source is a semiconductor light emitting element or an organic EL element.
The vehicle headlamp according to any one of claims 1 to 9, wherein the following expression (6) is satisfied, where Ls is a distance from a coordinate origin position to the first surface of the lens.
Ls ≧ F2 Formula (6)
The vehicle headlamp according to any one of claims 1 to 10, wherein the lens is shifted and decentered toward the light emitting surface side of the y axis (positive direction of the y axis) with respect to the z axis. .