JP4743142B2 - Vehicle lighting - Google Patents

Description

  The present invention relates to a vehicular lamp, and more particularly to a vehicular lamp that can efficiently use light from a light source.

  In a vehicular lamp having a light source and a reflector, a part of the reflected light from the reflector is shielded by the light source and is not irradiated in front of the lamp, so that light loss occurs. For this reason, in such a vehicular lamp, there is a problem that the light from the light source should be used efficiently.

  Further, for example, in a vehicular lamp such as a headlamp, a fog lamp, and a cornering lamp, diffusion light distribution control that smoothly attenuates the light intensity in the horizontal direction or the vertical direction is employed. Moreover, it is preferable that such diffused light distribution control is performed with high accuracy with a compact and simple configuration. The technique described in patent document 1 is known for the conventional vehicle lamp regarding this subject.

JP 2005-108555 A

  An object of this invention is to provide the vehicle lamp which can utilize the light from a light source efficiently.

To achieve the above object, a vehicular lamp according to the present invention includes a light source composed of a semiconductor light emitting element, a reflector that reflects light from the light source and irradiates the front of the lamp, and diffuses or diffuses light from the light source. e Bei a lens to irradiate the front of the widening to the lamp, the light source is disposed in front of the lamp than the reflector, forward of the lamp than said lens said light source an the optical axis of the reflector And a range in which the reflected light is shielded by the lens and is not irradiated in front of the lamp among the reflecting surfaces of the reflector is referred to as a reflected light loss range D, and is based on the optical axis of the reflector. A light incident range α from the light source to the reflector, a light incident range β from the light source to the lens, and a light incident range γ from the light source to the reflected light loss range D are defined. When a feature in that it has an incident range of light alpha in the reflector, the incident range of light beta in the lens, the relationship between the incident range of the light gamma is α>β> γ in the reflected light loss range D To do.

In this vehicular lamp, the lens is disposed on the optical axis of the reflector and in front of the lamp (forward with respect to the irradiation direction of the reflector) relative to the light source, so that the light from the light source is transmitted by both the lens and the reflector. Irradiates in front of the lamp. Thereby, there exists an advantage by which the light from a light source is utilized efficiently.
In this vehicular lamp, the size relationship between the reflector and the lens and the positional relationship between the light source and the light source depend on the relationship between the light incident range α from the light source to the reflector and the light incident range β from the light source to the lens. Be bound. Thereby, since the loss of light resulting from the positional relationship between the light source and the reflector is reduced, there is an advantage that the light from the light source is efficiently utilized.
Further, in this vehicular lamp, since the incident range γ of light to the reflected light loss range D is optimized, the reflected light from the reflector that is shielded by the lens and is not irradiated in front of the lamp is reduced. Thereby, there is an advantage that light loss is reduced and light from the light source is efficiently utilized.

  In the vehicular lamp according to the present invention, the light source is disposed on the optical axis of the reflector and on the optical axis of the lens.

  In this vehicular lamp, light from the light source properly enters both the reflector and the lens. Thereby, there exists an advantage by which the light from a light source is utilized efficiently in both a reflector and a lens.

  Further, in the vehicular lamp according to the present invention, the optical axis of the light source is oriented in the vertical direction when the lamp is installed.

  This vehicular lamp has an advantage that light distribution suitable for the lamp can be obtained.

  In addition, the vehicular lamp according to the present invention is such that when the angle formed by the reflected light of the reflector and the optical axis of the reflector is called a reflection angle θ ′, the reflected light in the incident range γ avoids the lens. The reflection angle θ ′ of the reflecting surface of the reflector in the incident range γ is defined so as to be irradiated in front of the light.

  In this vehicular lamp, since the reflected light in the incident range γ is emitted in front of the lamp while avoiding the lens, there is an advantage that the light from the light source is efficiently used without waste.

  Further, in the vehicle lamp according to the present invention, when the angle formed between the reflected light of the reflector and the optical axis of the reflector is called a reflection angle θ ′, at least a part of the reflecting surface of the reflector is a predetermined free-form surface. In addition, in the free-form surface, the reflection angle θ ′ of the reflected light changes n-th continuously as it goes from the center to the end of the reflector.

  In this vehicular lamp, the reflection angle θ ′ of the reflected light of the reflector changes continuously in the nth order from the center to the end of the reflector, so that it is approximately the center of the irradiation range (near the HV point). The intensity of the irradiation light changes smoothly from the edge toward the edge (diffuse light distribution pattern). In addition, since the reflection surface is a free-form surface, it is easy to set the reflection angle θ ′ to change continuously n-th order. That is, since the reflection angle θ ′ can be set in detail on a free-form surface, the accuracy of the luminous intensity distribution of the irradiated light is improved. Thereby, there exists an advantage which can perform the diffused light distribution control of a lamp accurately.

  Further, in the vehicular lamp according to the present invention, when an angle formed between the light emitted from the lens and the optical axis of the lens is referred to as an emission angle θ, at least a part of the exit surface of the lens is a predetermined free-form surface. In addition, in the free-form surface, the exit angle θ of the exit light changes continuously in the order of n from the center to the end of the lens.

  In this vehicular lamp, since the exit angle θ of the exit light of the lens changes continuously n-order from the center to the end of the lens, it starts from substantially the center of the irradiation range (near the HV point). The intensity of the irradiated light changes smoothly toward the end (diffuse light distribution pattern). Further, since the exit surface is a free-form surface, it is easy to set the exit angle θ to change n-th order continuously. That is, since the exit angle θ can be set in detail on a free-form surface, the accuracy of the luminous intensity distribution of the irradiated light is improved. Thereby, there exists an advantage which can perform the diffused light distribution control of a lamp accurately.

  In the vehicular lamp according to the present invention, the lens is disposed on the optical axis of the reflector and in front of the light source with respect to the light source (forward with respect to the irradiation direction of the reflector), so that light from the light source is transmitted between the lens and the reflector. Both are irradiated in front of the lamp. Thereby, there exists an advantage by which the light from a light source is utilized efficiently.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

  1 to 3 are a perspective view (FIG. 1), a plan view (FIG. 2), and a side view (FIG. 3) showing a vehicular lamp according to an embodiment of the present invention. FIG. 4 is an explanatory view showing the operation of the vehicular lamp described in FIG. FIG. 5 is a perspective view showing a reflector of the vehicle lamp shown in FIG. 6-8 is explanatory drawing which shows the structure and effect | action of the reflector described in FIG. 9-12 is explanatory drawing which shows the example of a design of the reflector described in FIG. FIG. 13 is a perspective view showing a lens of the vehicular lamp shown in FIG. 14-16 is explanatory drawing which shows the structure and effect | action of the vehicle lamp described in FIG. 17 and 18-3 are explanatory diagrams illustrating design examples of the lens illustrated in FIG.

[Vehicle lamp]
The vehicular lamp 1 is applied to, for example, a headlamp, a fog lamp, a cornering lamp, and the like, and includes a light source 2, a lens 3, and a reflector 4 (see FIGS. 1 to 3). The light source 2 is composed of a semiconductor light emitting element. The light source 2 includes, for example, a plurality of arranged LEDs (light emitting diodes), and emits light in a substantially hemispherical shape. The lens 3 is disposed in front of the light source 2 and diffuses or widens light from the light source 2 to irradiate the front of the lamp. The lens 3 is configured based on a convex lens made of resin or glass such as PMMA (Polymethylmethacrylate), for example. The reflector 4 is disposed behind the light source 2 and reflects the light from the light source 2 to irradiate the front of the lamp. The reflector 4 is configured by a parabolic free-form surface, for example.

  Here, an XYZ orthogonal coordinate system is taken with the optical axis of the lamp as the Z axis (see FIGS. 1 to 3). Further, the vertical direction is the Y axis and the horizontal direction is the X axis in the lamp installation state. At this time, the light source 2, the lens 3, and the reflector 4 are arranged as follows.

  First, the light source 2 is disposed on the optical axis Z. Next, the lens 3 is disposed on the optical axis Z and in front of the light source 2 (in front of the illumination direction of the lamp). At this time, the reference point O of the incident surface 31 of the lens 3 is arranged on the optical axis Z, and the optical axis of the lens 3 and the optical axis Z of the lamp coincide (the reference point O of the incident surface 31 of the lens 3). May not be arranged on the optical axis Z). Further, the light source 2 is disposed at the pseudo back focus point F of the lens 3. Next, the reflector 4 is disposed on the optical axis Z and behind the light source 2 (backward with respect to the illumination direction of the lamp). At this time, the reference point O ′ of the reflector 4 is arranged on the optical axis Z, and the optical axis of the reflector 4 and the optical axis Z of the lamp coincide (the reference point O ′ of the reflector 4 is on the optical axis Z). Does not have to be placed). Further, the light source 2 is disposed at the pseudo focus point F ′ of the reflector 4. That is, in this embodiment, the optical axis of the lens 3 and the optical axis of the reflector 4 are on a common optical axis Z. Further, the pseudo back focus point F of the lens 3 and the pseudo focus point F ′ of the reflector 4 coincide with each other, and the light source 2 is disposed on the points F and F ′.

  In the vehicular lamp 1, when the light source 2 emits light, the radiated light enters from the incident surface 31 of the lens 3 and is irradiated from the exit surface 32 of the lens 3 to the front of the lamp. Further, the radiated light is reflected by the reflecting surface of the reflector 4 and is irradiated in front of the lamp. Then, a predetermined light distribution pattern is formed by these irradiation lights (see FIG. 4).

  At this time, the lens 3 is disposed on the optical axis Z of the reflector 4 and in front of the lamp (in front of the irradiation direction of the reflector 4) with respect to the light source 2, so that the light from the light source 2 is transmitted to the lens 3 and the reflector. 4 irradiates the front of the lamp respectively (see FIG. 4). Thereby, there exists an advantage by which the light from a light source is utilized efficiently. For example, in a configuration in which the lamp is composed only of a light source and a reflector, a part of the reflected light from the reflector is shielded by the light source and is not irradiated in front of the lamp, resulting in light loss.

[Light source position]
In the vehicular lamp 1, the light source 2 is preferably disposed on the optical axis of the reflector 4 and on the optical axis of the lens 3 (see FIG. 3). In such a configuration, the light from the light source 2 properly enters both the reflector 4 and the lens 3. Thereby, there exists an advantage by which the light from the light source 2 is utilized efficiently in both the reflector 4 and a lens. For example, if the light source 2 is at a position deviated from the optical axis of the reflector (the optical axis of the lens), a desired light distribution cannot be obtained by the reflector (lens).

  For example, in this embodiment, the optical axis of the reflector 4 and the optical axis of the lens 3 coincide with the optical axis Z of the lamp (see FIG. 3). Further, the center of the light source 2 is arranged at a point on the optical axis Z where the pseudo back focus point F of the lens 3 and the pseudo focus point F ′ of the reflector 4 coincide. Therefore, the light from the light source 2 efficiently enters both the reflector 4 and the lens 3, and a desired light distribution is obtained by both the reflector 4 and the lens.

[Light axis direction of light source]
Further, in the vehicular lamp 1, it is preferable that the light source 2 is arranged so that the optical axis of the light source 2 faces the vertical direction (vertical direction upper side or vertical direction lower side) in the lamp installation state (FIG. 3). Thereby, there exists an advantage by which the light distribution suitable for the vehicle lamp 1 is obtained. For example, the configuration in which the optical axis of the light source 2 is directed upward in the vertical direction when the lamp is installed facilitates the light distribution for the high beam of the headlamp (see FIGS. 3 and 4). On the contrary, the configuration in which the optical axis of the light source 2 is directed downward in the vertical direction when the lamp is installed facilitates the light distribution for the fog lamp (not shown).

  For example, in this embodiment, the optical axis Z is set so as to face the traveling direction and the horizontal direction of the vehicle when the lamp is installed (see FIG. 1). In addition, the X axis is set in the horizontal direction and the horizontal direction of the vehicle, and the Y axis is set in the vertical direction. The light source 2 is on the optical axis Z of the lamp (on the optical axis of the lens 3 and on the optical axis of the reflector 4), and the pseudo back focus point F of the lens 3 and the pseudo focus point F ′ of the reflector 4 coincide with each other. (See FIG. 3). The light source 2 is arranged so that its optical axis (normal direction of the light emitting surface of the LED chip) coincides with the Y axis. Thereby, in the installation state of the lamp, the optical axis of the light source 2 is set so as to face the upper side in the vertical direction, and the light distribution for the high beam of the headlamp is realized (see FIG. 4).

[Light incident range on reflector and lens]
In the vehicular lamp 1, when the light incident range α from the light source 2 to the reflector 4 and the light incident range β from the light source 2 to the lens 3 are defined with reference to the optical axis of the reflector 4, It is preferable that the light incident range α in the reflector 4 and the light incident range β in the lens 3 have a relationship of α> β (see FIGS. 2 and 3).

  In such a configuration, the size relationship between the reflector 4 and the lens 3 and the positional relationship between the light source 2 and the reflector 4 are such that the light incident range α from the light source 2 to the reflector 4 and the light incident range β from the light source 2 to the lens 3 are as follows. It is restrained by the relationship. In addition, since the light incident range α of the reflector 4 and the light incident range β of the lens 3 have a relationship of α> β, an optical system having the reflector 4 as a main and the lens 3 as a sub is configured. Thereby, since the loss of the light resulting from the positional relationship of the light source 2 and the reflector 4 is reduced, there exists an advantage that the light from a light source is utilized efficiently. For example, in a configuration in which the light incident range α at the reflector and the light incident range β at the lens have a relationship of α <β (not shown), the reflected light of the reflecting surface of the reflector 4 is shielded by the lens 3 and the lamp. Since the range that is not irradiated in front of the light (hereinafter referred to as the reflected light loss range D; see FIGS. 2 and 3) increases, the loss of light increases.

  In the above configuration, when the light incident range γ from the light source 2 to the reflected light loss range D is defined with reference to the optical axis Z of the reflector 4, the light incident range α in the reflector 4 and the lens 3 It is preferable that the incident range β of light and the incident range γ of light in the reflected light loss range D have a relationship of α> β> γ (see FIGS. 2 and 3). In such a configuration, since the incident range γ of the light to the reflected light loss range D is optimized, the reflected light from the reflector 4 that is shielded by the lens 3 and is not irradiated in front of the lamp is reduced. Thereby, there is an advantage that light loss is reduced and light from the light source is efficiently utilized.

  For example, in this embodiment, first, the light source 2 is configured by an LED chip that emits light in a substantially hemispherical shape (see FIGS. 2 and 3). The light source 2 is arranged on the optical axis Z of the reflector 4 and at the pseudo focus point F ′ of the reflector 4. In addition, an incident range α of light to the reflector 4 is defined based on the optical axis Z of the reflector 4. The light source 2 is disposed on the optical axis Z of the lens 3 (optical axis of the reflector 4) and at the pseudo back focus point F of the lens 3 (pseudo focus point F 'of the reflector 4). Further, an incident range β of light to the lens 3 is defined with reference to the optical axis Z of the lens 3.

  In addition, an incident range γ of light into the reflected light loss range D is defined with reference to the optical axis Z of the reflector 4. Further, the reflected light loss range D coincides with the diameter of the lens 3 (height from the optical axis Z). The diameter and shape of the reflector 4 and the diameter and shape of the lens 3 are defined so that these incident ranges α, β, and γ have a relationship of α> β> γ. Further, the incident range α of the light to the reflector 4 is in the range of α> 90 [deg]. Thereby, each incident range (alpha), (beta), (gamma) is optimized, and the light from a light source is utilized efficiently.

When there is a restriction on the diameter of the reflector 4 (height H from the Z axis), the numerical values and relationships of the incident ranges α, β, γ are defined within the restriction. For example, in this embodiment, the incident range α is set to α = 100 [deg] (opening size φ100 [mm] of the reflector 4, pseudo-focus distance 21 [mm]), and the incident range β is β = 55 [deg]. (Pseudo back focus distance 8 [mm]) and the incident range γ is set to γ = 30 [deg] .

[Reflecting surface of reflector in incident range γ]
Further, in this vehicular lamp 1, when the angle formed between the reflected light of the reflector 4 and the optical axis Z of the reflector 4 is called a reflection angle θ ′, the reflected light in the incident range γ avoids the lens 3 and avoids the lamp. It is preferable that the reflection angle θ ′ of the reflecting surface of the reflector 4 in the incident range γ is defined so as to be irradiated forward (see FIGS. 6 and 7). In such a configuration, since the reflected light in the incident range γ is emitted in front of the lamp while avoiding the lens 3, there is an advantage that the light from the light source 2 is efficiently used without waste.

  For example, in this embodiment, the reflection angle θ ′ in the incident range γ is set to θ ′ = 10 [deg] at the central portion (reference point O ′) of the reflector 4 (see FIGS. 6 and 7). Thereby, the reflected light from the incident range γ is irradiated to the front of the lamp while avoiding the lens 3 arranged in front of the reflector 4. Further, the reflection angle θ ′ continuously decreases by n-th as it goes from the central portion of the reflector 4 to the radially outer side of the reflector 4, and θ ′ = 0 [deg] at the boundary position of the incident range γ. Is set as follows. As a result, the reflected light in the incident range γ is irradiated in front of the lamp in a diffused light distribution pattern (see FIG. 8).

[Design example of free-form surface of reflector]
For example, in the diffused light distribution control of the lamp, the reflector 4 shown in FIGS. 6 and 7 is designed as follows (see FIGS. 5 and 6 and FIGS. 8 to 12). Here, a high beam light distribution pattern (see FIG. 4) of the headlamp will be described as an example.

  First, in designing, a rectangular LED chip is employed as the light source 2 (see FIG. 5). In the light source 2, the radiation intensity distribution of the emitted light substantially matches the Lambertian curve. The light source 2 is arranged so that the center point of the LED chip coincides with the pseudo focus point F ′ of the reflector 4 and the normal direction of the LED chip is directed upward in the vertical direction (Y-axis positive direction). Further, the reflecting surface of the reflector 4 is constituted by a parabolic free-form surface, and this reflecting surface has a parameter having parameters in two directions of a rotation direction (u direction) and a radiation direction (w direction) with respect to the reference point O ′. Is set (see FIG. 9).

Next, in a horizontal sectional view (XZ sectional view) of the reflector 4, a single color having an arbitrary wavelength (for example, 656 [nm]) from the pseudo focus point F ′ to each node point P ′ (u, w) on the reflecting surface. Optical path tracking is performed with light incident. Next, a range (incidence range γ) for performing diffusion light distribution control is set, and a node point P ′ (diffusion start point P ′ ₀ (reference point 0) and diffusion end point P ′ ₀₁ ) corresponding to the boundary of this range. Is selected (see FIG. 6). Then, the emission angle θ ′ on the reflecting surface is set so that the reflected light of the node point P ′ changes in the radial direction of the reflector 4 at a predetermined diffusion light distribution angle around the optical axis Z. Specifically, the reflected light of the node point P ′ ₀ is reflected at the reflection angle θ ′ _{0 with} respect to the optical axis Z, and the node point P ′ ₀₁ at the outer end of the range of the diffused light distribution control. The reflecting surface of the reflector 4 is set so that the reflected light is parallel to the optical axis Z (θ ′ ₀₁ = 0).

Next, the reflection angle θ ′ of the reflected light is set for each node point P ′ within the range where diffusion light distribution control is performed (between the diffusion start point P ′ ₀ and the diffusion end point P ′ ₀₁ ) ( (See FIG. 6). At this time, based on a ₀₁ 'reflection angle theta of _{01' 0} and the diffusion end point P 'reflected angle theta of _0' spread start point P, 'reflection angle theta' each node point P is set. Specifically, the reflection angle θ ′ decreases (to θ ′ = 0) as it goes in the radiation direction of the reflector 4 (the direction from the diffusion start point P ′ ₀ to the diffusion end point P ′ ₀₁ , the w direction). As shown in FIG. 9, interpolation is performed using an n-order function (see FIG. 9).

In this embodiment, the reflection angle θ ′ _{0 of} the diffusion start point P ′ ₀ is set to θ ′ ₀ = 10 [deg] in the horizontal sectional view of the reflector 4 (see FIG. 6). Then, the reflection angle θ ′ of each node point P ′ from the diffusion start point P ₀ to the diffusion end point P ₀₁ is set by interpolation with a 1.0 order function. That is, the reflection angle θ ′ of each node point P ′ is set so that the reflection angle θ ′ gradually approaches θ ′ = 0 as it goes from the diffusion start point P ₀ to the diffusion end point P ₀₁ . In addition, each node point P ′ on the reflecting surface is set so that the node point group on the right side in the horizontal direction and the node point group on the left side in the horizontal direction are symmetric about the optical axis Z in the horizontal sectional view of the reflector 4. Is done.

  In the range where the diffused light distribution control is not performed (the range outside the incident range γ in the radial direction of the reflector 4), the reflected light is reflected so that the reflected light is parallel to the optical axis Z (θ ′ = 0). The angle θ ′ is set.

Next, in the vertical cross-sectional view (XZ cross-sectional view) of the reflector 4, the same processing as that in the horizontal cross-sectional view (XZ cross-sectional view) is performed to determine a node point group on the reflecting surface (see FIG. 7). ). For example, a boundary point in the vertical direction upper side of the range (incidence range gamma) subjected to diffused light distribution control with diffusion end point P _'02. In this case, 'are set to ₍₀₂ = 0 [deg], the diffusion starting point P parallel to the optical axis Z is _02' reflection angle theta of the reflected light at ₀₂ 'diffusion end point _{P θ)' 0 (θ '} 0 = 10 The reflection angle θ of each reflected light from [deg]) to the diffusion end point P ′ ₀₂ is set by interpolation with a 1.0 order function.

  Next, in the front view (XY plan view) of the reflector 4, a node point group on the reflecting surface in the range between the horizontal cross section (XZ cross section) and the vertical cross section (XZ cross section) of the reflector 4 is determined (FIG. 9). At this time, based on the reflection angle θ ′ of the node point group in the horizontal section and the reflection angle θ ′ of the node point group in the vertical section, the interpolation by the n-order function is performed in the rotation direction (u direction) around the reference point O ′. And the exit angle θ ′ of the entire reflecting surface is set. Then, a node point group on the reflecting surface is set so that the reflected light is reflected at the reflection angle θ ′.

  Next, a free curved surface of the reflecting surface is formed so as to pass through all the set node points. At this time, a NURBS curved surface (see FIG. 12) is performed with an arbitrarily set rank and control points. As a result, a free-form surface is formed such that the reflection angle θ ′ changes parametrically in the rotation direction (u direction) and the radiation direction (w direction) about the optical axis Z.

  FIGS. 10A and 10B show an image (emitted chip image) of the light source 2 projected on the screen via the reflector 4 described above. In these drawings, an image of the light source 2 in the range of the upper side in the vertical direction and the left side in the horizontal direction is shown. The V axis indicates the vertical direction, and the H axis indicates the horizontal direction. Note that the image of the light source 2 in the range on the upper side in the vertical direction and on the right side in the horizontal direction is V-axis symmetric with respect to the image of the light source 2 in the range on the upper side in the vertical direction and on the left side in the horizontal direction.

  The reflector 4 is provided with a light distribution having a high luminous intensity zone for obtaining visibility of 50 [m] or more in a region radially outside the incident range γ (FIGS. 6 and 6). 7 and FIG. 10-1). Further, in a region radially outward from γ, a light distribution is applied such that the reflected light is irradiated to the upper side and the side more than 20 [m] away from the lens 3 (FIG. 10-2). reference).

[Diffusion light distribution control by lens]
In this embodiment, the lens 3 has a substantially semicircular shape and is disposed only on the upper side in the vertical direction with respect to the optical axis Z (see FIGS. 1, 3 and 13). The lens 3 performs the following diffusion light distribution control.

  First, an angle formed between the light emitted from the lens 3 and the optical axis Z is referred to as an emission angle θ (see FIGS. 14 and 15). At this time, at least a part of the exit surface 32 of the lens 3 is a free-form surface, and the exit angle θ of the exit light is the center of the lens 3 (for example, the reference point O or the optical axis Z). The lens 3 is configured so as to change (increase) continuously n-th as it goes from the end toward the end. That is, the free-form surface of the exit surface 32 is formed so that the exit light is smoothly (nth-order continuously) inclined radially outward of the lens 3 as it goes from the center to the end of the lens 3. Such a free-form surface is defined by a mathematical formula (for example, a NURBS curved surface) for forming predetermined control light.

  In the vehicular lamp 1, the exit angle θ of the light emitted from the lens 3 continuously changes (increases) from the center to the end of the lens 3, so that the substantially central portion (H The intensity of the irradiated light smoothly changes (attenuates) from the vicinity of the −V point toward the end (diffuse light distribution pattern) (see FIGS. 4 and 16). Further, since the exit surface is a free-form surface, it is easy to set the exit angle θ to change n-th order continuously. That is, since the exit angle θ can be set in detail on a free-form surface, the accuracy of the luminous intensity distribution of the irradiated light is improved. Thereby, there exists an advantage which can perform the diffused light distribution control of a lamp accurately.

  For example, in this embodiment, the emission angle θ ′ of the emitted light gradually increases toward the outer side in the radial direction of the lens 3 with the optical axis Z of the reflector 4 as the center in the horizontal sectional view of the lens 3. (See FIG. 14). In such a configuration, a light distribution pattern in which the irradiation light is smoothly diffused in the horizontal direction is formed (see FIG. 16). Thereby, at the time of a high beam, a sidewalk and an opposite lane are illuminated appropriately, and the visibility of the irradiation range with respect to the horizontal direction is improved by smooth light intensity attenuation. In addition, in the cross-sectional view of the lens 3 in the vertical direction, the emission angle θ of the emitted light gradually increases as it goes outward in the radial direction of the lens 3 with the optical axis Z of the lens 3 as the center (see FIG. 15). In such a configuration, a light distribution pattern in which the irradiation light is smoothly diffused in the vertical direction is formed (see FIG. 16). Thereby, at the time of a high beam, an upper road sign and a tree are appropriately illuminated, and the visibility of the irradiation range with respect to the upper vertical direction is improved by smooth light intensity attenuation.

  In addition, in this vehicle lamp 1, it is not restricted to the above but it replaces with the lens 3 which has a free-form surface, and the existing lens may be employ | adopted.

  In the vehicular lamp 1, it is preferable that the incident surface 31 of the lens 3 is a flat surface, a convex surface or a concave surface having a single diameter (spherical surface), or other simple shapes. In such a configuration, since the exit surface 32 (free curved surface) is designed based on the entrance surface 31 having a simple shape, there is an advantage that the design of the exit surface 32 becomes easy. For example, in this embodiment, the entrance surface 31 of the lens 3 is a flat surface (see FIGS. 14 and 15).

[Design example of free-form surface of lens]
For example, in the diffusion light distribution control of the lamp, the lens 3 is designed as follows (see FIGS. 13 to 18). Here, a high beam light distribution pattern (see FIG. 4) of the headlamp will be described as an example.

  First, in designing, a rectangular LED chip is employed as the light source 2 (see FIG. 13). In the light source 2, the radiation intensity distribution of the emitted light substantially matches the Lambertian curve. Further, the light source 2 is arranged so that the center point of the LED chip coincides with the pseudo back focus point F of the lens 3 and the normal direction of the LED chip is directed upward in the vertical direction (Y-axis positive direction). Further, the entrance surface 31 of the lens 3 is a flat surface, and a patch having parameters in two directions of the rotation direction (u direction) and the radiation direction (w direction) is set on the entrance surface 31 around the reference point O. (See FIG. 17). Note that the same setting is performed when the incident surface 31 of the lens 3 is formed of a convex surface or a concave surface made of a spherical surface having a single diameter. Further, the interval between patches can be set arbitrarily.

Next, an arbitrary wavelength (for example, 656 [nm]) from the pseudo back focus point F to each node point P (u, w) of the patch on the incident surface 31 in the horizontal sectional view of the lens 3 (XZ sectional view). The monochromatic light is incident and the optical path is traced. Next, a range to be subjected to diffusion light distribution control is set, and node points P (diffusion start point P ₀ (reference point 0) and diffusion end point P ₁ ) corresponding to the boundary of this range are selected (see FIG. 14). ). The exit angle θ at the exit surface 32 is set so that the incident light at the node points P ₀ and P ₁ spreads outward in the radial direction of the lens 3 at a predetermined diffusion light distribution angle with the optical axis Z as the center. The Specifically, the incident light at the node point P _{0 on} the optical axis Z is emitted at an emission angle θ = 0 parallel to the optical axis Z, and at the outer end of the range of diffusion light distribution control. The exit surface 32 of the lens 3 is set so that incident light at a certain node point P ₁ exits radially outward of the lens 3 at a predetermined exit angle θ = θ ₁ .

Next, for the incident light at each node point P within the range where diffusion light distribution control is performed (between the diffusion start point P ₀ and the diffusion end point P ₁ ), the emission angle θ of the emission light is set (see FIG. 14). At this time, the emission angle θ of each emission light is set with reference to the emission angle θ = 0 with respect to the incident light at the diffusion start point P _{0 and} the emission angle θ = θ ₁ with respect to the incident light at the diffusion end point P ₁ . Specifically, the n-th order is such that the emission angle θ increases in the radiation direction centered on the reference point O (the direction from the diffusion start point P ₀ toward the diffusion end point P ₁ , the w direction). Interpolation is performed using a function (see FIG. 9). Then, the node point group of the exit surface 32 with respect to the node point group of the entrance surface 31 is set according to each set exit angle θ.

In this embodiment, the emission angle θ ₁ of the emitted light with respect to the incident light at the diffusion end point P ₁ is set to θ ₁ = 10 [deg] in the horizontal sectional view of the lens 3 (see FIG. 14). Then, the exit angle θ of each exit light from the diffusion start point P ₀ to the diffusion end point P ₁ is interpolated by a 1.0 order function. In addition, each node point on the exit surface 32 is set so that the node point group on the right side in the horizontal direction and the node point group on the left side in the horizontal direction are symmetric about the optical axis Z in the horizontal sectional view of the lens 3. The

Next, in the vertical cross-sectional view (XZ cross-sectional view) of the lens 3, the same processing as that in the horizontal cross-sectional view (XZ cross-sectional view) is performed, and the node point of the exit surface 32 with respect to the node point group of the entrance surface 31 A group is determined (see FIG. 15). For example, a boundary point in the vertical direction upper side of the range subjected to diffused light distribution control with diffusion end point P _2. At this time, is set to the injection angle theta ₂ is theta ₂ = 2 of the emitted light [deg] in the diffusion end point P _2, the exit angle theta of the emitted light reaching the diffusion end point P ₁ from the spread start point P ₀ 1 . Interpolated by 0th order function.

  Next, in the front view (XY plane view) of the lens 3, the node point group of the emission surface 32 in the range between the horizontal cross section (XZ cross section) and the vertical cross section (XZ cross section) of the lens 3 is determined ( FIG. 15). At this time, based on the exit angle θ of the node point group in the horizontal section and the exit angle θ of the node point group in the vertical section, interpolation by an n-order function is performed in the rotation direction (u direction) around the reference point O. Thus, the exit angle θ of the entire exit surface 32 is set. Then, the node point group of the emission surface 32 is set so that the emission light is emitted at the emission angle θ.

  Next, the free-form surface of the exit surface 32 is formed so as to pass through all the set node points. At this time, a NURBS curved surface (see FIG. 12) is performed with an arbitrarily set rank and control points. As a result, a free-form surface is formed such that the emission angle θ of the emitted light changes parametrically around the optical axis Z in the rotation direction (u direction) and the radiation direction (w direction).

  FIGS. 18A to 18C show images (emitted chip images) of the light source 2 projected on the screen through the lens 3 described above. In these drawings, an image of the light source 2 in the range of the upper side in the vertical direction and the left side in the horizontal direction is shown. The V axis indicates the vertical direction, and the H axis indicates the horizontal direction. The image of the light source 2 in the range on the upper side in the vertical direction and on the right side in the horizontal direction is V-axis symmetric with respect to the image of the light source 2 in the range on the upper side in the vertical direction and on the left side in the horizontal direction.

  As shown in FIGS. 18-1 to 18-3, in this lens 3, the exit angle θ of the exit surface 32 increases from the center of the lens 3 toward the horizontal end (see FIG. 14). It can be seen that the image of the light source 2 projected on the screen is diffused in the horizontal direction (see FIG. 16). Further, since the exit angle θ of the exit surface 32 increases from the center of the lens 3 toward the upper end in the vertical direction (see FIG. 15), the image of the light source 2 projected on the screen is directed upward in the vertical direction. As can be seen from FIG.

  In such a light distribution pattern by the lens 3, a high luminous intensity zone having a maximum altitude zone is maintained in the central portion (near the HV point) (see FIG. 4). Further, the irradiation light is diffused while smoothly attenuating the luminous intensity in the horizontal direction around the optical axis Z, and is also diffused while smoothly attenuating the luminous intensity in the vertical direction (at an angle not as high as the horizontal direction). . Thereby, a light distribution pattern having a wide irradiation range in the horizontal direction and smoothly attenuating the light intensity is formed. Further, a light distribution is provided to obtain the visibility of the upper side and the side farther than 20 [m].

  As described above, the vehicular lamp according to the present invention is useful in that the light from the light source can be efficiently used.

It is a perspective view which shows the vehicle lamp concerning the Example of this invention. It is a top view which shows the vehicle lamp concerning the Example of this invention. It is a side view which shows the vehicle lamp concerning the Example of this invention. It is explanatory drawing which shows the effect | action of the vehicle lamp described in FIG. It is a perspective view which shows the reflector of the vehicle lamp described in FIG. It is explanatory drawing which shows the structure and effect | action of the reflector described in FIG. It is explanatory drawing which shows the structure and effect | action of the reflector described in FIG. It is explanatory drawing which shows the structure and effect | action of the reflector described in FIG. It is explanatory drawing which shows the example of a design of the reflector described in FIG. It is explanatory drawing which shows the example of a design of the reflector described in FIG. It is explanatory drawing which shows the example of a design of the reflector described in FIG. It is explanatory drawing which shows the example of a design of the reflector described in FIG. It is explanatory drawing which shows the example of a design of the reflector described in FIG. It is a perspective view which shows the lens of the vehicle lamp described in FIG. It is explanatory drawing which shows the structure and effect | action of the vehicle lamp described in FIG. It is explanatory drawing which shows the structure and effect | action of the vehicle lamp described in FIG. It is explanatory drawing which shows the structure and effect | action of the vehicle lamp described in FIG. It is explanatory drawing which shows the example of a design of the lens described in FIG. It is explanatory drawing which shows the example of a design of the lens described in FIG. It is explanatory drawing which shows the example of a design of the lens described in FIG. It is explanatory drawing which shows the example of a design of the lens described in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle lamp 2 Light source 3 Lens 31 Incident surface 32 Ejection surface 4 Reflector

Claims (6)

A light source composed of a semiconductor light emitting device, e Bei the reflector to be irradiated to the front of the lamp to reflect light from said light source and a lens for irradiating the front of the lamp by diffusion or widening the light from the light source,
The light source is disposed in front of the lamp with respect to the reflector, the lens is disposed on the optical axis of the reflector and in front of the lamp with respect to the light source , and
A range of the reflecting surface of the reflector where the reflected light is shielded by the lens and is not irradiated in front of the lamp is referred to as a reflected light loss range D, and from the light source to the reflector with reference to the optical axis of the reflector. When defining the light incident range α, the light incident range β from the light source to the lens, and the light incident range γ from the light source to the reflected light loss range D,
The vehicular lamp characterized in that the light incident range α in the reflector, the light incident range β in the lens, and the light incident range γ in the reflected light loss range D have a relationship of α>β> γ. .   The vehicular lamp according to claim 1, wherein the light source is disposed on an optical axis of the reflector and on an optical axis of the lens.   The vehicular lamp according to claim 2, wherein an optical axis of the light source faces a vertical direction when the lamp is installed. When the angle formed by the reflected light of the reflector and the optical axis of the reflector is called a reflection angle θ ′, the incident range is such that the reflected light in the incident range γ is irradiated in front of the lamp while avoiding the lens. The vehicular lamp according to claim 1, wherein a reflection angle θ ′ of the reflecting surface of the reflector at γ is defined. When an angle formed between the reflected light of the reflector and the optical axis of the reflector is called a reflection angle θ ′, at least a part of the reflecting surface of the reflector is formed of a predetermined free-form surface, and the free-form surface reflects the vehicular lamp according to any one of claims 1-4 for the reflection angle theta 'is the n-th order continuously varies along the edge from the central portion of the reflector of light. When the angle formed between the light emitted from the lens and the optical axis of the lens is called the emission angle θ,
At least a part of the exit surface of the lens is formed of a predetermined free-form surface, and in the free-form surface, the exit angle θ of the exit light changes continuously in the order of n from the center to the end of the lens. The vehicle lamp according to any one of claims 1 to 5 .

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