JP2019179648A - Vehicular lighting fixture - Google Patents

Abstract

To suppress variation in a light irradiation direction even in a lighting fixture using a light guide having a curved emission surface of light.SOLUTION: A lighting fixture (1) includes: a light source (30); and light guide members (10, 20). The light guide member (20) has a plurality of reflection surfaces (21), makes light incident from an incidence surface (22) and guides the light by total reflection, makes light beam reflected on a reflection surface (21) into light beam having an incidence angle smaller than a critical angle, and emits the light beam from a side face (24). A surface perpendicular to an emission direction is defined as a projection surface and a center line (C) is curved on the projection surface. A position in a long-axis direction from the incidence surface (22) of the side face (24) in which light beam reflected on the reflection surface 21 is emitted is positioned to be far from the reflected reflection surface (21). A plane (S) including a normal line (N) in a minute region including a point (P) on the center line (C) and light beam (L) which passes the point (P) and is emitted from an emission surface (11) coincides with a tangent line of the center line (C) at the point (P) on the projection surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicular lamp.

  Patent Document 1 describes, for example, a surface light emitting device 1 including a light guide portion 2 and a light emitting surface portion 3. The light guide portion 2 is formed of a transparent member having a substantially rod shape having a cross section of four sides, a guide portion lens 2c is formed on one surface, and a diffusion cut portion 2b is formed on the other surface facing the rod portion. A light introduction part 2a having an LED lamp 4 is provided at at least one end of the light source. The light emitting surface part 3 includes a number of cylindrical lens-like light emitting surface part lenses 3a in accordance with the number of light guide parts used. The light guide portion and the light emitting surface portion are opposed to each other with an appropriate interval so that almost the entire surface of the light emitting surface portion lens emits light by light from the guide portion lens. Light from the LED lamp 4 is introduced into the light guide portion 2. At this time, the light reaching the boundary between the light guide portion 2 and the atmosphere travels toward the other end of the light guide portion 2 while repeating internal reflection. Light that reaches the guide lens 2c at an angle less than the total internal reflection angle is emitted from the lens 2c to the outside, that is, to the atmosphere.

JP 2005-285667 A

  However, in the surface light emitting device 1 of Patent Document 1, when the guide lens 2c is formed in a bent shape as viewed from the light emitting surface portion 3, it is difficult to keep the light irradiation direction constant.

  The present invention has been made in view of the above-described circumstances, and even when a light guide formed with a curved shape from which light is emitted as viewed from the direction in which light is emitted is used. The variation in the irradiation direction can be suppressed.

  A vehicular lamp according to the present invention is a lamp mounted on a vehicle, and includes a light source that emits light and a plurality of first reflecting surfaces formed along a major axis direction, and the light emitted from the light source Light is incident from an incident surface formed at an end, the incident light is guided by total reflection in the major axis direction, and a light beam reflected by the first reflective surface has an incident angle that is greater than a critical angle. A first light guide member that emits from the side surface as a small light beam, and a second light guide member that enters the light beam emitted from the side surface and exits from the output surface, and is emitted from the output surface. The direction in which the first light beam having the highest luminous intensity is emitted among the light rays is defined as an emission direction, and a plane perpendicular to the emission direction is defined as a projection surface. The emission surface includes a first long side and a first long side. And on the projection plane, the first long side and the second long side A line on the emission surface passing through the center between the two long sides is a center line, the center line is curved on the projection surface, and a light beam reflected by the first reflection surface is emitted. The position of the long axis direction from the end portion of the side surface is positioned farther than the reflected first reflecting surface, and the normal line of the minute region including the point on the center line and the point are A plane including the second light beam having the highest luminous intensity emitted from the emission surface coincides with a tangent of the center line at the point on the projection surface.

  According to the present invention, variation in the light irradiation direction can be suppressed even when a light guide formed with a curved surface from which light is emitted when viewed from the direction in which the light is emitted is used.

It is a perspective view which shows the structure of the vehicle lamp which concerns on 1 of embodiment. It is a block diagram which shows the structure of the light guide rod of the vehicle lamp which concerns on 1 of embodiment. It is a block diagram which shows the structure of the light guide rod of the vehicle lamp which concerns on 1 of embodiment. It is sectional drawing which shows the structure of the light guide rod of the vehicle lamp which concerns on 1 of embodiment. It is sectional drawing which shows the structure of the vehicle lamp which concerns on 1 of embodiment. It is a block diagram which shows the structure of the vehicle lamp which concerns on 1 of embodiment. It is a block diagram which shows the structure of the vehicle lamp which concerns on 1 of embodiment. It is a fragmentary sectional view which shows the structure of the light guide rod of the vehicle lamp which concerns on 1 of embodiment. It is an optical path figure of the light ray which advances the inside of the light guide rod of the vehicle lamp which concerns on 1 of embodiment. It is a figure showing the refraction of the light ray in the substance surface. It is an optical path figure of a light ray shown with a perspective view of a vehicular lamp concerning 1 of an embodiment. It is an optical path figure of the light ray which advances the inside of the light-guide plate of the vehicle lamp which concerns on 1 of embodiment. It is the figure which showed the form with which the vehicle lamp which concerns on 1 of embodiment was mounted in the vehicle.

  In the surface light emitting device 1 of Patent Document 1, a plurality of diffusion cut portions 2 b are provided on the back surface of the light guide portion 2. The diffusion cut portion 2b is for emitting the light incident from the light guide portion 2 from the guide portion lens 2c. The diffusion cut portion 2b is visually recognized by an observer when the surface light emitting device 1 is not emitting light. For this reason, the appearance of the surface light emitting device 1 when not emitting light is impaired.

  In the embodiment described below, for example, the appearance of the surface light emitting device 1 when it is not emitting light is suppressed by the diffusion cut portion 2b.

  The light beam emitted from the guide part lens 2 c of the light guide part 2 is inclined with respect to the direction of light traveling in the light guide part 2. In this case, when the guide lens 2c and the light emitting surface 3 are bent as viewed from the direction in which the light from the surface light emitting device 1 is emitted, the light emitted from the guide lens 2c is bent first. It is necessary to further incline toward a certain light emitting surface portion 3. Therefore, the light beam emitted from the light emitting surface portion 3 is emitted inclined with respect to the direction in which the light of the surface light emitting device is irradiated.

<Explanation of coordinates in the figure>
In the following embodiments, for ease of explanation, the coordinate axes of the xyz orthogonal coordinate system and the coordinate axes of the x′y′z ′ orthogonal coordinate system are shown in the drawings. In the following drawings, the scale of dimensions may be different depending on the constituent elements.

  First, the coordinate axes of the xyz coordinate system are shown.

  The z-axis direction is a direction in which the lamp irradiates light. The z-axis direction is the main emission direction of the light emitted from the lamp. The emission direction is a direction in which a light beam having the highest luminous intensity is emitted from the light emitted from the emission surface 11. The direction in which the lamp emits light is the direction in which the light beam having the highest luminous intensity is emitted among the emitted light. The direction in which the lamp emits light is the optical central axis direction in which the lamp emits light. That is, the z-axis direction is the direction of the main optical axis of the lamp.

  A plane perpendicular to the radiation direction of the maximum luminous intensity of light emitted from the vehicular lamp 1 is an xy plane. A plane perpendicular to the radiation direction of the maximum luminous intensity of light emitted from the emission surface 11 is an xy plane. The emission direction is the + z-axis direction. The plane perpendicular to the emission direction is the xy plane.

  In the following embodiments, in order to facilitate the explanation, the illumination direction of the lamp is assumed to be the front of the vehicle as an example. The + z-axis direction is, for example, the front of the vehicle. The −z-axis direction is, for example, the rear of the vehicle. Therefore, “viewing from the exit direction” and “viewing from the front of the vehicle” means viewing the −z direction side from the + z direction side. “Looking from the rear of the vehicle” means viewing the + z-axis direction side from the −z-axis direction side. Moreover, a front view is a figure when the vehicle lamp 1 is seen from the front of the vehicle.

  The y-axis direction is a normal direction with respect to the ground when the vehicle is placed in a stationary state on the ground. The + y axis direction is, for example, the upward direction. That is, the + y-axis direction is a sky direction. The y-axis direction is, for example, the downward direction. That is, the −y axis direction is the direction of the ground.

  The plane perpendicular to the xy plane and perpendicular to the plane (zx plane) on which the vehicle is placed stationary on the ground is the yz plane.

  “Viewing from above the vehicle” means viewing the −y axis direction side from the + y axis direction side. On the other hand, “viewing from below the vehicle” means viewing the + y-axis direction side from the −y-axis direction side. The top view is a view of the vehicular lamp 1 as seen from above the vehicle.

  The x axis is an axis perpendicular to the yz plane. The + x-axis direction is the left side when looking forward from the rear of the vehicle. The −x-axis direction is the right side when looking forward from the rear of the vehicle.

  Next, the coordinate axes of the x'y'z 'coordinate system are shown in each figure.

The x′y′z ′ coordinates are coordinates along the center line C ₂ of the emission surface 11 of the light guide plate 10. The center line C ₂ of the emission surface 11 is a line passing through the centers of the upper side 11 a and the lower side 11 b on the emission surface 11. The upper side 11 a and the lower side 11 b are the long sides of the emission surface 11. The upper side 11a is opposed to the lower side 11b. Center line C ₂ includes a curved portion.

The z ′ axis is parallel to the center line C ₂ of the light guide plate 10. Alternatively, the z ′ axis is parallel to the tangent line of the center line C ₂ of the light guide plate 10. The x′y ′ plane is a plane perpendicular to the z ′ axis. x'y 'plane is a plane perpendicular to the tangent of the vertical plane or center line C ₂ on the center line C _2. And x'y 'plane section perpendicular to the center line C _2. That is, the x′y ′ plane is a plane perpendicular to the tangent at the point P ₁ on the center line C ₂ of the emission surface 11. The + z ′ axis direction is a direction in which light travels through the light guide rod 20, for example.

  The y ′ axis is, for example, an axis parallel to the emission surface 11 on the x′y ′ plane. For example, on the x′y ′ plane, the emission surface 11 has a linear shape. The upper side 11a is, for example, the side on the + y′-axis direction side of the emission surface 11. The lower side 11b is, for example, a side on the −y′-axis direction side of the emission surface 11.

For example, the y ′ axis is parallel to a straight line connecting the center P ₄ of the light guide bar 20 and the midpoint P ₅ of the reflection surface 12 of the light guide plate 10 on the x′y ′ plane. Point P ₄ is a point on the center line C ₁ of the light guide bar 20. The + y ′ axis direction is the direction from the point P ₄ to the point P ₅ . The + y′-axis direction is a direction from the center P _{4 of the} light guide bar 20 toward the midpoint P _{5 of the} reflecting surface 12. -Y 'axis direction is a direction from the midpoint _{P 5} of the reflecting surface 12 to the center _{P 4} of the light pipe 20.

  The x ′ axis is an axis perpendicular to the y′z ′ plane. The x ′ axis is orthogonal to the y ′ axis on the x′y ′ plane. For example, the x ′ axis is parallel to the bottom surface 13 of the light guide plate 10 on the x′y ′ plane. For example, the x ′ axis is parallel to the upper surface 14 of the light guide plate 10 on the x′y ′ plane. The + x′-axis direction is the direction from the reflecting surface 12 to the emitting surface 11. The light traveling through the light guide plate 10 toward the exit surface 11 travels in the + x′-axis direction.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.

<Configuration of vehicle lamp 1>
Below, the structure of the vehicle lamp 1 is demonstrated with reference to FIGS.

  FIG. 1 is a perspective view showing the configuration of the vehicular lamp 1. As shown in FIG. 1, the vehicular lamp 1 includes a light guide plate 10, a light guide bar 20, and a light source 30.

<< Light source 30 >>
The light source 30 emits light. The light source 30 is disposed at the end of the light guide bar 20. The light source 30 is installed, for example, facing one end surface (incident surface 22) of the light guide bar 20. For example, the light emitting surface 31 of the light source 30 and the incident surface 22 of the light guide bar 20 are parallel to each other. Further, a straight line connecting the center of the incident surface 22 and the center of the light emitting surface 31 is, for example, perpendicular to the light emitting surface 31. The light guide bar 20 is an example of a light guide member.

≪Light guide bar 20≫
FIG. 2 is a configuration diagram (top view) showing the configuration of the light guide rod of the vehicular lamp. FIG. 3 is a configuration diagram (front view) showing the configuration of the light guide rod of the vehicular lamp. FIG. 4 is a cross-sectional view showing the configuration of the light guide rod of the vehicular lamp. The D1-D1 cross section shown in FIGS. 2 and 7 is the x′y ′ plane. The D2-D2 cross section shown in FIGS. 3 and 6 is the x′y ′ plane.

  The light guide bar 20 guides light emitted from the light source 30. The light guide bar 20 makes light emitted from the light source 30 enter from the end thereof. The light guide bar 20 guides the light emitted from the light source 30 by reflecting the light from the side surface. The light guide bar 20 guides the incident light in the major axis direction by total reflection. The major axis direction of the light guide bar 20 is the z′-axis direction. The light guide bar 20 emits a light beam having an incident angle on the side surface 24 smaller than the critical angle from the side surface 24. The light guide bar 20 makes the light beam reflected by the reflecting surface 21 a light beam having an incident angle on the side surface 24 smaller than the critical angle. Light rays having an incident angle on the side surface 24 smaller than the critical angle are emitted from the side surface 24. The light guide bar 20 emits the guided light toward the light guide plate 10.

The light guide bar 20 includes an incident surface 22 and a reflective surface 21. The light guide bar 20 has, for example, a bar shape extending along a curved line bent in two dimensions or three dimensions. That is, the center line _{C 1} of the light guide bar 20 is, for example, a two-dimensional curved or three-dimensional curves.

  The incident surface 22 is incident on the light emitted from the light source 30. The incident surface 22 is formed at the end of the light guide bar 20. The incident surface 22 is, for example, an end surface of the light guide bar 20.

  For example, the incident surface 22 is disposed to face the light emitting surface 31 of the light source 30. For example, a straight line connecting the center of the light emitting surface 31 of the light source 30 and the center of the incident surface 22 of the light guide bar 20 is perpendicular to the incident surface 22 of the light guide bar 20.

The reflection surface 21 is formed on the side surface of the light guide bar 20. The reflecting surface 21 is formed along the long axis direction of the light guide bar 20. The reflection surface 21 is formed with a flat surface, for example. If the center line C ₁ is a straight line, the tip of the top line 25 of the reflection plane 21 is, for example, is perpendicular to the traveling direction of light (z 'axis). The top line 25 is, for example, on the x′y ′ plane. In the case where the reflected light is bent centerline C ₁ position of the side surface 24 to reach the summit line 25 is inclined with respect to the light traveling direction (z 'axis).

  The reflecting surface 21 reflects incident light. The light reflected by the reflecting surface 21 reaches the side surface. The incident angle with respect to the side surface of the light reflected by the reflecting surface 21 is smaller than the critical angle. Therefore, the light reflected by the reflecting surface 21 is emitted from the side surface.

  The reflecting surface 21 is, for example, a prism. The reflective surface 21 may be a printed pattern that diffusely reflects incident light, for example. The print pattern is, for example, a dot pattern.

A plurality of reflecting surfaces 21 are formed in the direction along the center line C ₁ of the light guide bar 20. In the first embodiment, the plurality of reflecting surfaces 21 are continuously formed in the direction along the center line C ₁ of the light guide bar 20. In the first embodiment, the plurality of reflecting surfaces 21 are formed side by side in the direction along the center line C ₁ of the light guide bar 20.

<< Light guide plate 10 >>
The light guide plate 10 includes an upper surface 14, a lower surface 13, and an emission surface 11. The light guide plate 10 can include a reflective surface 12. The light guide plate 10 receives a light beam emitted from the side surface 24 of the light guide bar 20. The light guide plate 10 emits the incident light beam from the emission surface 11.

  The light guide plate 10 has, for example, a plate shape. The emission surface 11 and the reflection surface 12 are formed on, for example, plate-shaped side surfaces. The light guide plate 10 reflects the light incident from the light guide rod 20 by the reflection surface 12 and guides it to the emission surface 11. The light guide plate 10 has, for example, a two-dimensional or three-dimensional curved shape.

FIG. 5 is a cross-sectional view showing the configuration of the vehicular lamp 1. 5 shows the cross section perpendicular to the center line C _2. The center line C ₂ contains curves. Therefore, "the cross section perpendicular to the center line C _2" is a cross-section perpendicular to the tangent of the centerline C _2. In FIG. 5, x'y'z 'coordinates are used.

The light guide bar 20 is disposed along the light guide plate 10. Therefore, to coincide with the plane perpendicular to the center line C to a plane perpendicular to ₁ to the center line C _2. Plane perpendicular to the center line C ₂ is also perpendicular centerline C _1.

  As shown in FIG. 5, the lower surface 13 of the light guide plate 10 is a surface on the −y′-axis direction side of the light guide plate 10. The upper surface 14 of the light guide plate 10 is a surface on the + y′-axis direction side of the light guide plate 10. The lower surface 13 and the upper surface 14 are disposed to face each other.

Center line _{C 2} is the x'y 'plane, which is a line on the exit surface 11 passing through the center of the upper side 11a and lower side 11b. Center line C ₂ is curved in Y'z 'plane. In the first embodiment, for example, on a cross section perpendicular (x'y 'plane) to the center line C ₂ of the exit surface 11 of the light guide plate 10 is parallel to the lower surface 13 and upper surface 14. Further, in the cross section perpendicular the center line C ₂ exit surface 11 of the light guide plate 10 (x'y 'plane), for example, are perpendicular to the output surface 11 and bottom surface 13. On a cross section perpendicular to the center line C ₂ of the exit surface 11 of the light guide plate 10 (x'y 'plane), for example, is perpendicular to the emission surface 11 and the upper surface 14. Further, in the cross section perpendicular to the center line _{C 2} of the exit surface 11 of the light guide plate 10 (x'y 'plane), the angle _{A 4} of the reflecting surface 12 and lower surface 13 is, for example, 45 degrees. The center line C ₂ is indicated by a point in the x'y 'plane.

  The emission surface 11 includes an upper side 11a and a lower side 11b. The lower side 11b is opposed to the upper side 11a.

FIG. 6 is a configuration diagram (front view) showing the configuration of the vehicular lamp 1. As shown in FIG. 6, the plane S is, the normal vector N ₂ of the small region including the P ₁ arbitrary point on the exit surface 11, a plane including the light beam emitted to the point P ₁ from the street exit surface 11 is there. Point _{P 1} is, for example, a point on the center line _{C 2.} Here, light L ₅ emitted from the exit surface 11 is parallel to z-axis.

The angle A ₀ is an angle between the plane S and the ground (zx plane) when the emission surface 11 is viewed from the front (+ z axis side) of the vehicle. A point on the upper side 11a of the closest exit surface 11 to the point _{P 1} to point _{P 2.} The point P ₂ is a point on the upper side 11 a of the emission surface 11. Further, the point on the lower side 11b of the nearest exit surface 11 to the point _{P 1} and point _{P 3.} Point P ₃ is a point on the lower side 11 b of the emission surface 11. The angle of the tangent line and the ground and (xz plane) of the upper side 11a at point _{P 2,} for example, equal to the angle _{A 0.} The angle of the tangent line and the ground and (xz plane) of the upper side 11b at the point _{P 3} is, for example, equal to the angle _{A 0.}

FIG. 7 is a configuration diagram (top view) showing the configuration of the vehicular lamp 1. Hereinafter, with reference to FIG. 7, the case of being projected onto the zx plane (viewed from the top of the vehicle) will be described. A straight line extended from the point _{P 1} to the z-axis direction and the straight line SL _1. The light beam L ₅ emitted from the point P ₁ travels on the straight line SL ₁ . An angle formed by the normal line Nv of the emission surface 11 at the point P ₁ and the straight line SL ₁ (light ray L ₅ ) is defined as an angle A ₁ . A straight line SL ₂ straight lines overlaps the ray reaching the point P ₁ proceeds through the light guide plate 10. The acute angle formed between the straight line SL ₁ and the straight line SL ₂ and the angle _{A 2.} Let the refractive index of the light guide plate 10 be the refractive index np. Angle _{A 2} is represented by the following formula (1). However, arcsin (X) means an inverse trigonometric function. arcsin (X) is an angle Y such that sin (Y) = X. Further, “·” in the following formula means multiplication. Further, “/” in the following expression means division.
A ₂ = arcsin ((1 / np) · sin (A ₁ )) (1)

<Shape and position relationship on the cross section perpendicular to the center line C _2>
Referring to FIG. 5 below, illustrating the positional relationship between the shape of the cross section perpendicular to the center line C _2. That is a description of on the cross section perpendicular to the center line C _2. Cross section perpendicular to the center line C ₂ is a plane parallel to the x'y 'plane.

  The cross-sectional shape of the light guide bar 20 in the x′y ′ plane is, for example, a circular shape. Note that the cross-sectional shape of the light guide rod 20 in the x′y ′ plane is not limited to a circular shape as long as light can be guided.

Point _{P 4} is a point on the center line _{C 1.} That is, the point P ₄ is the center point of the light guide bar 20. A point P ₅ is the midpoint of the reflecting surface 12 of the light guide plate 10. The point P ₄ is located on the extension line of the perpendicular line SL ₃ extending from the point P ₅ to the lower surface 13.

The radius R of the light guide bar 20 is smaller than the distance from the point P ₄ to the lower surface 13.

The reflection surface 21 is formed on the side surface of the light guide bar 20. The reflecting surface 21 is formed on the extension of the vertical line SL _3. The reflecting surface 21 is arranged on the opposite side of the light guide plate 10 with respect to the point P _4. The reflecting surface 21 is disposed on an extension of a line connecting the point P ₄ and the point P _5. That is, the reflective surface 21 is farther from the point _{P 5} than the point _{P 4.}

<Shape and positional relationship of the section including the center line C _2>
FIG. 8 is a partial cross-sectional view showing the configuration of the light guide rod 20 of the vehicular lamp 1. Figure 8 shows a cross-sectional shape of the light guide rod 20 in the plane including the center line C ₁ and the perpendicular SL _3. FIG. 8 shows a shape in which the light guide bar 20 is cut along a plane that includes the center line C ₁ of the light guide bar 20 and is parallel to the y′z ′ plane. The center line C ₁ Since comprises a curve, including a curved cross-sectional shape of the light guide bar 20. FIG. 8 shows the cross-sectional shape of the curved surface as a plane.

This will be described below with reference to FIG. That is a description of on the cross section of the light pipe 20 in the plane including the center line C ₁ and the perpendicular SL _3.

Light traveling inside the light guide bar 20, for example, traveling in the direction of the center line C ₁ while being reflected by the side surfaces 23, 24 of the light guide bar 20. In FIG. 8, the light traveling inside the light guide rod 20 travels in the + z′-axis direction. The reflecting surface 21 reflects light traveling inside the light guide bar 20. The reflecting surface 21 reflects light toward the side surface 24 of the light guide bar 20. For example, the reflecting surface 21 reflects light toward the opposing side surface 24.

The angle A ₃ is an angle formed by the side surface 23 and the reflecting surface 21. The angle A ₃ is an angle formed by the center line C ₁ and the reflecting surface 21. The refractive index of the light guide rod 20 is defined as a refractive index nb. Angle _{A 3} satisfy the following formula (2a).
A ₃ = (90−arcsin ((1 / nb) · sin (A ₁ ))) / 2 (2a)

The constant α is a minute constant. The constant α varies depending on the incident angle of the light traveling in the light guide rod 20 on the reflecting surface 21. The constant α is adjusted so that the direction of light emitted from the vehicular lamp 1 is the + z-axis direction. Angle _{A 3} of the reflective surface 21 is expressed by the following equation (2b).
A ₃ = (90−arcsin ((1 / nb) · sin (A ₁ ))) / 2 + α (2b)

<Principle for emitting light from the light guide rod 20>
FIG. 9 is an optical path diagram of light rays traveling in the light guide rod 20 of the vehicular lamp 1. FIG. 9 shows a shape in which the light guide bar 20 is cut along a plane that includes the center line C ₁ of the light guide bar 20 and is parallel to the y′z ′ plane, as in FIG. 8. FIG. 9 is a diagram for explaining the behavior of light reflected by the reflecting surface 21. The principle that the light emitted from the light source 30 enters the light guide rod 20 from the incident surface 22 and is emitted from the light guide rod 20 will be described with reference to FIG.

  First, the light emitted from the light source 30 enters the light guide rod 20 from the incident surface 22.

  For example, the light incident on the light guide bar 20 travels through the light guide bar 20 while repeating total reflection. However, some light is incident on the reflecting surface 21. And the light path of the light reflected by the reflecting surface 21 is changed. The light whose optical path has been changed is refracted by the side surface 24 of the light guide bar 20 when it is emitted from the light guide bar 20. The light refracted by the side surface 24 of the light guide bar 20 travels in the direction of the light guide plate 10. The side surface 24 is a surface facing the reflecting surface 21.

Angle _{A 3} of the reflective surface 21 is defined by equation (2). Therefore, light rays incident on the reflecting surface 21 is emitted from the light guide rod 20 at exit angle A _1. The traveling light in the light guide rod 20 travels in the + z ′ axis direction. Therefore, the light emitted from the light guide rod 20 travels in a direction inclined in the + z ′ axis direction with respect to the normal line (y ′ axis) of the side surface 24. Exit angle A ₁ shown in FIG. 9, 'on a plane, y'Y'z an angle relative to the axis.

  The position in the major axis direction (z ′ axis) from the incident surface 22 of the side surface 24 from which the light beam reflected by the reflecting surface 21 is emitted is located farther from the reflected reflecting surface 21. Here, the major axis direction is the + z′-axis direction.

The exit angle A ₁ emitted from the light guide bar 20 is equal to the incident angle when entering the light guide plate 10. Further, the incident surface 13a and the exit surface 11 of the light guide plate 10 are optically parallel surfaces. Therefore, the emission angle from the output surface 11 is equal to the angle A _1.

The width 211 of the reflecting surface 21 is adjusted so that the light guide bar 20 emits light uniformly over the entire length. In general, the width 211 of the reflecting surface 21 increases as the distance from the light source 30 increases. Width 211 is the length of the z 'axis direction of the reflecting surface 21 (the center line _{C 1} direction).

<Principle for emitting light from the light guide plate 10>
Next, the principle in which the light emitted from the light guide bar 20 enters the light guide plate 10 and is emitted from the light guide plate 10 will be described with reference to FIGS.

  FIG. 10 is a diagram showing the refraction of light rays on the material surface. In describing the principle for emitting light from the light guide plate 10, the light refraction formula will be described with reference to FIG. 10.

The normal vector N is a normal vector of the tangent plane 40 at the point P ₆ on the material surface 50. A point P ₆ is an intersection of the light ray L ₄ incident on the material surface 50 and the material surface 50. In FIG. 10, the substance surface 50 is indicated by a broken line. Vector O is the direction vector of the ray L ₅ emitted. Vector I is the direction vector of the ray L ₄ incident. Vectors N, I, and O are unit vectors. The refractive index n1 is the refractive index of the medium on the incident side. The refractive index n2 is the refractive index of the medium on the emission side. “X” indicates an outer product of vectors. The light refraction formula is a three-dimensional extension of Snell's law. The refraction formula of the light beam is expressed by the following formula (3).
N × O = (n ₁ / n ₂ ) · N × I (3)

When the incident light ray L ₄ is reflected by the material surface 50, the refractive index n ₁ and the refractive index n ₂ are equal (n ₁ = n ₂ ). Then, equation _{(3) (n 1 / n} 2) in becomes _{1 ((n 1 / n 2} ) = 1).

The light refraction formula means that light refraction and light reflection occur in the plane S ₂ including the direction vector I and the normal vector N of the incident light beam L ₄ . That is, the plane S ₂ includes the direction vector I, the normal vector N, and the vector O. Direction vector I, the normal vector N and vector O is a vector on the plane S _2. In FIG. 10, in order to show the plane S _2, it has signed a normal N and the direction vector I by broken lines.

  The light emitted from the light guide bar 20 enters the light guide plate 10 from the incident surface 13 a of the light guide plate 10. In the first embodiment, the incident surface 13 a is formed on the lower surface 13 of the light guide plate 10. Note that the incident surface 13 a is not necessarily formed on the lower surface 13 of the light guide plate 10. For example, a step or the like may be provided between the incident surface 13 a and the lower surface 13 of the light guide plate 10.

  FIG. 11 is an optical path diagram of light rays shown in a perspective view of the vehicular lamp 1.

  As shown in FIG. 11, the light emitted from the light source 30 enters the light guide bar 20 from the incident surface 22 of the light guide bar 20. The incident surface 22 is formed at the end of the light guide bar 20. The light incident on the light guide bar 20 is guided by total reflection in the major axis direction (z′-axis direction) of the light guide bar 20. Of the guided light, a light beam whose incident angle to the side surface 24 is smaller than the critical angle is emitted from the side surface 24.

  Light emitted from the side surface 24 of the light guide bar 20 enters the light guide plate 10. The light emitted from the side surface 24 of the light guide bar 20 enters the light guide plate 10 from the incident surface 13a. The light incident on the light guide plate 10 is reflected by the reflecting surface 21. The light reflected by the reflection surface 21 reaches the emission surface 11. The light that reaches the emission surface 11 is emitted from the emission surface 11.

FIG. 12 is an optical path diagram of light rays traveling in the light guide plate 10 of the vehicular lamp 1. As shown in FIG. 12, the direction of the vector progresses light incident on the light guide plate 10 is a direction vector I _1. The light of the direction vector I ₁ reaches the reflecting surface 12. The light that reaches the reflecting surface 12 is reflected by the reflecting surface 12. The direction vector O ₁ is a direction vector of light reflected by the reflecting surface 12. Light reaching the reflecting surface 12 is totally reflected within the plane S _21. Plane _{S 21} corresponds to the plane _{S 2} shown in FIG. 10. The plane S ₂₁ is a plane including the direction vector I ₁ and the normal vector N ₁ . Normal vector N _1, the light is the normal vector at the reflecting surface 12 the point on which is reflected.

The light reflected by the reflecting surface 12 travels according to the light beam refraction formula (3). The light reflected by the reflection surface 12 proceeds in the direction of the direction vector O _1. The light reflected by the reflecting surface 12 travels in the direction of the emitting surface 11. Direction vector _{I 2} of light reaching the emission surface 11 is equal to the direction vector _{O 1.} The direction vector I ₂ is a direction vector of light rays incident on the exit surface 11. The direction vector O ₁ is a direction vector of a light ray emitted from the reflecting surface 12.

Light incident on the emission surface 11 in the direction vector I ₂ proceeds according to the refraction type light (3). Light reaching the emission surface 11 is refracted in the plane S _22. Plane _{S 22} corresponds to the plane _{S 2} shown in FIG. 10. Plane _{S 22} is a plane including the direction vector _{I 2} and the normal vector _{N 2.} The planar _{S 22} includes a direction vector _{O 2.} Direction vector _{I 2,} normal vector _{N 2} and the vector _{O 2} is a vector on the plane _{S 22.} Light refracted by the exit surface 11 travels in the direction of the direction vector O _2. In this case, the direction vector O ₂ coincides with the + z axis direction.

As shown in FIG. 5, in the x'y 'plane, the angle between the reflecting surface 12 and lower surface 13 is A _4. Also, as shown in FIG. 6, on the xy plane, the angle formed by the tangent to the center line C _{2 at} the point P ₁ and the ground (xz plane) is equal to the angle A ₀ . In the xy plane, the angle of the tangent line and the ground and (xz plane) of the upper side 11a at point _{P 2} is equal to the angle _{A 0.} In the xy plane, the angle of the tangent line and the ground and (xz plane) of the upper side 11b at the point _{P 3} is equal to angle _{A 0.} The point P ₁ is a point on the emission surface 11. A point on the upper side 11a of the closest exit surface 11 to the point _{P 1} to point _{P 2.} Further, the point on the lower side 11b of the nearest exit surface 11 to the point _{P 1} and point _{P 3.}

The plane S ₂₂ is a plane including a normal vector N ₂ of a minute region including the point P ₁ on the emission surface 11 and a light ray emitted through the point P ₁ . Rays which is the point P ₁ as emitted, for example, is emitted to the + z axis direction. The angle A ₀ is an angle formed by the plane S _{22 and the} ground (zx plane) when the emission surface 11 is viewed from the front (+ z axis side) of the vehicle.

A plane S ₂₂ including the normal N _{2 of the} minute region including the point P ₁ on the center line C ₂ and the light beam L ₅ having the highest luminous intensity that passes through the point P ₁ and is emitted from the emission surface 11 is defined on the xy plane. This coincides with the tangent of the center line C _{2 at} the point P ₁ .

Here, the plane S ₂₂ is optically the same plane as the plane S ₂₁ . Here, “optically” means that a light beam that is structurally reflected by a reflecting surface or the like and whose traveling direction is changed is represented by a single optical axis as an optical system. . “Optically” means that the optical system is represented by one optical axis on one plane.

  As described above, the vehicular lamp 1 according to the first embodiment emits light forward of the vehicle. The vehicular lamp 1 can obtain a luminance distribution with increased uniformity on the exit surface 11.

  Further, the light guide plate 10 does not include a fine structure such as the reflecting surface 21. The light guide bar 20 is disposed on the −y axis direction side of the light guide plate 10. The light guide bar 20 includes a reflective surface 21. Thus, when the vehicular lamp 1 is turned off, the fine structure such as the reflecting surface 21 cannot be seen through the emission surface 11. Thereby, the design of the vehicular lamp 1 can be improved.

  As the light source 30 in the vehicular lamp 1, various things such as an incandescent bulb or a laser diode can be used in addition to an LED (Light Emitting Diode).

  The light guide rod 20 may be formed of, for example, an acrylic resin, a phenyl-based or dimethyl-based silicon resin, or the like. The light guide plate 10 may be formed of, for example, an acrylic resin, a phenyl-based or dimethyl-based silicon resin, or the like.

  FIG. 13 is a view showing a form in which the vehicular lamp 1 is mounted on the vehicle 9. FIG. 13 is a view of the vehicle 9 as viewed from the front, and shows the right half of the vehicle 9. The vehicular lamp 1 is disposed below the headlight 91. FIG. 13 shows a windshield 92 and a tire 93.

  The vehicular lamp 1 can be applied to, for example, a vehicle width lamp. Further, the vehicular lamp 1 is applied to a tail lamp, a direction indicator, a brake lamp, a backlight, a front fog lamp, a daylight, a cornering lamp, a hazard lamp, and the like. Alternatively, the vehicular lamp 1 can be applied to a combination lamp of these combinations.

  In each of the above-described embodiments, there are cases where terms such as “parallel” or “vertical” indicating the positional relationship between components or the shape of the component are used. These represent that a range that takes into account manufacturing tolerances and assembly variations is included. For this reason, when the description showing the positional relationship between the parts or the shape of the part is included in the claims, it indicates that the range including a manufacturing tolerance or an assembly variation is taken into consideration.

  Moreover, although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

DESCRIPTION OF SYMBOLS 1 Vehicle lamp, 10 Light guide plate, 11 Output surface, 11a Upper side, 11b Lower side, 12 Reflective surface, 13 Lower surface of light guide plate, 13a Incident surface, 14 Upper surface of light guide plate, 20 Light guide rod, 21 Reflective surface, 211 Prism Width, 22 entrance surface, 23, 24 side surface, 25 top line, 30 light source, 31 light emitting surface, 40 tangential plane, 50 material surface, 9 vehicle, 91 headlight, 92 windshield, 93 tire, A ₀ , A ₁ , A ₂ , A ₃ , A ₄ angles, C ₁ , C ₂ centerline, E ₁ , E ₂ , E ₃ enlarged view, I incident light, L ₁ , L ₂ , L ₃ , L ₄ , L ₅ light, N , N ₁ , N ₂ normal vector, O, O1 ray direction vector, P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ points, R radius, S ₁ , S ₂ plane, SL ₁ , SL ₂ , SL ₃ straight line, Nv normal, α constant number.

Claims (2)

A lamp mounted on a vehicle,
A light source that emits light and a plurality of first reflecting surfaces formed along a major axis direction, and the light emitted from the light source is incident from an incident surface formed at an end portion, and the incident light A first light guide member that emits light reflected by the first reflecting surface from the side surface as a light beam having an incident angle smaller than a critical angle;
A second light guide member that enters the light beam emitted from the side surface and emits the light beam from the emission surface;
The direction in which the first light beam having the highest luminous intensity is emitted among the light beams emitted from the emission surface is defined as an emission direction.
A plane perpendicular to the emission direction is a projection plane,
The emission surface includes a first long side and a second long side facing the first long side,
On the projection plane, a line on the emission surface passing through the center between the first long side and the second long side is a center line,
The center line is curved on the projection plane;
The position of the major axis direction from the incident surface of the side surface from which the light beam reflected by the first reflective surface is emitted is located farther than the reflected first reflective surface.
A plane including the normal of the minute region including the point on the center line and the second light ray having the highest luminous intensity that passes through the point and is emitted from the exit surface is the position of the center line at the point on the projection plane. A vehicle lamp that matches the tangent.   The second light guide member includes a second reflection surface, and the light incident from the first light guide member is reflected by the second reflection surface and guided to the emission surface. Vehicle lamps.

Images