JP5647499B2 - Vehicle lighting - Google Patents

Description

  The present invention relates to a vehicular lamp.

  Conventionally, as a vehicular lamp such as a headlight for an automobile, a lamp using a semiconductor light emitting element and a phosphor as a light source is known (see, for example, Patent Document 1). In this type of vehicle lamp, by irradiating the phosphor with excitation light (for example, blue light) from the semiconductor light emitting element, the light emitted by excitation of the phosphor (for example, yellow light) and the excitation light are mixed and visible. Light (for example, white light) is emitted, and this visible light is projected forward of the vehicle by an optical system such as a projection lens.

Japanese Patent No. 4124445

  However, in the above conventional vehicle lamp, a part of the excitation light is regularly reflected by the phosphor and is emitted as it is from the projection lens or the like without being mixed into a predetermined color. Partial color unevenness occurs.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the vehicle lamp which can suppress the color nonuniformity of a projection image.

In order to solve the above-mentioned problem, the invention described in claim 1
A semiconductor light emitting device;
A phosphor that receives excitation light emitted from the semiconductor light emitting element and emits visible light;
A condensing optical system for condensing the excitation light emitted from the semiconductor light emitting element toward one surface of the phosphor;
A projection lens that projects visible light emitted from the phosphor to the front of the vehicle;
In a vehicle lamp comprising:
The projection lens has a diffusing portion for diffusing the excitation light incident on the projection lens from the phosphor, and is disposed to face one surface of the phosphor,
The diffusing portion is formed in a portion of the projection lens that is irradiated with the excitation light that is condensed by the condensing optical system and specularly reflected by the phosphor .

Invention according to claim 2,
A semiconductor light emitting device;
A phosphor that receives excitation light emitted from the semiconductor light emitting element and emits visible light;
A condensing optical system for condensing the excitation light emitted from the semiconductor light emitting element toward one surface of the phosphor;
A projection lens that projects visible light emitted from the phosphor to the front of the vehicle;
In a vehicle lamp comprising:
The projection lens has a focal point located in the vicinity of the phosphor, and has a diffusing portion that diffuses the excitation light incident on the projection lens from the phosphor, and faces the other surface of the phosphor. Arranged so that
The diffusing portion is formed by performing uneven processing on a portion of the projection lens that is irradiated with the excitation light condensed by the condensing optical system and transmitted through the phosphor. It is characterized by.

The invention according to claim 3 is the vehicle headlamp according to claim 1 or 2 ,
The semiconductor light emitting element emits laser light.

  According to the present invention, since the projection lens has a diffusing portion that diffuses the excitation light incident on the projection lens from the phosphor, when a part of the excitation light that has not been made visible by the phosphor enters the projection lens. The excitation light is diffused by the diffusion unit. Therefore, it is possible to prevent the excitation light from being emitted from the projection lens with the intensity emitted from the semiconductor light emitting element, and to suppress color unevenness in the projected image.

It is a sectional side view of the vehicle lamp in 1st embodiment. It is a figure for demonstrating the optical path in the vehicle lamp in 1st embodiment. It is a sectional side view of the vehicle lamp in 2nd embodiment. It is a figure for demonstrating the optical path in the vehicle lamp in 2nd embodiment.

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

[First embodiment]
FIG. 1 is a side sectional view of a vehicular lamp 3 according to a first embodiment of the present invention.
As shown in this figure, the vehicular lamp 3 is a so-called direct projection headlight, and includes a laser diode (hereinafter referred to as LD) 31, a condenser lens 37, a phosphor 32, and a projection lens 35. I have.

  Among these, the LD 31 is a semiconductor light emitting element according to the present invention, and emits blue laser light as excitation light of the phosphor 32 upward. The LD 31 has a laser emission port that is long in the left-right direction (the direction perpendicular to the paper in FIG. 1), and emits laser light that is wide in the left-right direction.

  The condensing lens 37 is a condensing optical system according to the present invention. The condensing lens 37 is disposed above the LD 31 and directs the blue light emitted upward from the LD 31 toward the main surface of the phosphor 32 disposed further upward. To collect light. More specifically, the condensing lens 37 condenses the blue light from the LD 31 to the approximate center in the thickness direction through the main surface of the phosphor 32.

  The phosphor 32 is a fluorescent material that emits yellow light when excited by receiving the blue light emitted from the LD 31. The phosphor 32 is disposed above the condenser lens 37 with the main surface facing forward and obliquely downward. Yes. When the phosphor 32 receives blue light, the blue light scattered by the phosphor 32 is mixed with yellow light, so that white light is emitted radially. The phosphor 32 is configured to receive blue light from the LD 31 collected by the condenser lens 37 on the main surface and emit white light radially from the main surface to the front surface. Is formed to be substantially the same as the area of the blue light condensing spot diameter. Therefore, the phosphor 32 emits white light like a point light source having substantially the same size as the condensing spot diameter of blue light.

  The projection lens 35 is an aspherical plano-convex lens having a convex front surface, and the fluorescent lens 32 is opposed to the main surface of the phosphor 32 so that the phosphor 32 is positioned on the optical axis Ax along the front-rear direction. Located in front of the body 32. The projection lens 35 has an object-side focal point located in the vicinity of the phosphor 32 and projects white light emitted from the phosphor 32 forward of the vehicle.

  In addition, a diffusing portion S is formed on the rear surface of the projection lens 35. The diffusing portion S is formed in a portion of the rear surface of the projection lens 35 that is irradiated with blue light that is condensed by the condensing lens 37 and regularly reflected by the phosphor 32 (see FIG. 2A). . The diffusing unit S diffuses the blue light that is regularly reflected by the phosphor 32 and is incident on the projection lens 35.

FIGS. 2A and 2B are diagrams for explaining an optical path in the vehicular lamp 3.
In the vehicular lamp 3 having the above configuration, as shown in FIG. 2A, the blue light (excitation light) emitted from the LD 31 is condensed on the phosphor 32 by the condenser lens 37, and most of the blue light is excited. White light is emitted forward. At this time, part of the blue light condensed on the phosphor 32 is not white light but is regularly reflected by the phosphor 32 toward the projection lens 35, but is incident on the diffusion portion S on the rear surface of the projection lens 35. Therefore, the blue light can be prevented from being emitted from the projection lens 35 with the intensity emitted from the LD 31.
As shown in FIG. 2B, the white light emitted from the phosphor 32 is irradiated from the projection lens 35 forward of the vehicle.

  According to the vehicular lamp 3 described above, the blue light that is specularly reflected without being converted into white light by the phosphor 32 is diffused by the diffusing portion S, so that the projection lens 35 remains with the intensity of the blue light emitted from the LD 31. Can be prevented, and as a result, color unevenness of the projected image can be suppressed.

  Further, if the blue light, which is laser light, is emitted as it is outside the lamp, it is not preferable in terms of safety to the human body (eye safety), but the blue light is emitted from the projection lens 35 with the high intensity emitted from the LD 31. Since this can be prevented, this safety can be ensured.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the component similar to said 1st embodiment, and the description is abbreviate | omitted.

FIG. 3 is a side sectional view of the vehicular lamp 4 according to the second embodiment of the present invention.
As shown in this figure, the vehicular lamp 4 includes an LD 41, a condenser lens 47, and a phosphor 42 in addition to a projection lens 35 configured in the same manner as in the first embodiment, and is blue. The vehicle lamp 3 is different from the vehicle lamp 3 in the first embodiment in that light is transmitted forward from the rear surface of the phosphor 42.

The LD 41 is disposed so as to emit blue light forward, and is otherwise configured in the same manner as the LD 31 in the first embodiment.
The condensing lens 47 is a condensing optical system according to the present invention, and is disposed in front of the LD 41 and directs the blue light emitted forward from the LD 41 toward the rear surface of the phosphor 42 disposed further forward. Collect light. More specifically, the condensing lens 47 condenses the blue light from the LD 41 through the rear surface of the phosphor 42 to the approximate center in the thickness direction.

  The fluorescent material 42 is the same fluorescent material as the fluorescent material 32 in the first embodiment, and is disposed in front of the condenser lens 47 with the rear surface supported by the translucent member 421. The phosphor 42 receives the blue light from the LD 41 collected by the condenser lens 47 from the rear and emits white light radially toward the front projection lens 35 so that the front surface of the projection lens 35 It is arranged in a state of facing the rear surface. In addition, the phosphor 42 is irradiated with blue light that has been condensed by the condenser lens 47 and transmitted forward through the phosphor 42 to a portion of the rear surface of the projection lens 35 where the diffusion portion S is formed. (See FIG. 4A). The phosphor 42 is formed so that the area of the front surface and the rear surface is substantially the same as the area of the blue light condensing spot diameter.

4A and 4B are diagrams for explaining the optical path in the vehicular lamp 4.
In the vehicular lamp 4 having the above configuration, as shown in FIG. 4A, blue light (excitation light) emitted from the LD 41 is condensed on the phosphor 42 by the condenser lens 47, and most of them are collected. White light is emitted forward. At this time, a part of the blue light collected on the phosphor 42 is not white light but passes through the phosphor 42 and travels toward the projection lens 35, but is incident on the diffusion portion S on the rear surface of the projection lens 35. Since the light is diffused, the blue light can be prevented from being emitted from the projection lens 35 with the intensity emitted from the LD 41.
As shown in FIG. 4B, the white light emitted from the phosphor 42 is irradiated from the projection lens 35 forward of the vehicle.

  According to the vehicle lamp 4 described above, the same effects as those of the vehicle lamp 3 in the first embodiment can be obtained. That is, since the blue light transmitted through the phosphor 42 without being converted into white light by the phosphor 42 is diffused by the diffusion portion S, the blue light is emitted from the projection lens 35 with the intensity emitted from the LD 41. As a result, color unevenness of the projected image can be suppressed, and safety to the human body can be ensured.

  It should be noted that the present invention should not be construed as being limited to the first and second embodiments described above, and of course can be modified or improved as appropriate.

  For example, although the LDs 31 and 41 have been described as semiconductor light emitting elements according to the present invention, the semiconductor light emitting elements are not limited to laser diodes, and may be light emitting diodes or the like.

  In addition, the LDs 31 and 41 emit blue light, and the phosphors 32 and 42 emit yellow light by the blue light. However, the present invention is not limited to this, and other configurations (excitation light and fluorescence) can be obtained. Combination with the body). Furthermore, the light emitted from the phosphors 32 and 42 is not limited to white light, and may be visible light of another color.

  In addition, the diffusing portion S is formed on a portion of the rear surface of the projection lens 35 that is irradiated with the blue light that is regularly reflected by the phosphor 32 or the blue light that is transmitted through the phosphor 42. It may not be formed over the entire range of the part. Specifically, depending on the output of the specularly reflected or transmitted blue light, the diffuser is limited to a range smaller than the portion irradiated with the blue light in consideration of color unevenness and safety of the projected image. S may be formed, and for example, it may be formed so as to be reduced to half the peak power of the blue light emitted from the LDs 31 and 41.

3,4 Vehicle lamps 31, 41 LD (semiconductor light emitting element)
32, 42 Phosphor 35 Projection lenses 37, 47 Condensing lens (condensing optical system)
S diffusion part

Claims (3)

A semiconductor light emitting device;
A phosphor that receives excitation light emitted from the semiconductor light emitting element and emits visible light;
A condensing optical system for condensing the excitation light emitted from the semiconductor light emitting element toward one surface of the phosphor;
A projection lens that projects visible light emitted from the phosphor to the front of the vehicle;
In a vehicle lamp comprising:
The projection lens has a diffusing portion for diffusing the excitation light incident on the projection lens from the phosphor, and is disposed to face one surface of the phosphor,
The vehicular lamp , wherein the diffusing portion is formed in a portion of the projection lens that is irradiated with the excitation light that is condensed by the condensing optical system and specularly reflected by the phosphor. . A semiconductor light emitting device;
A phosphor that receives excitation light emitted from the semiconductor light emitting element and emits visible light;
A condensing optical system for condensing the excitation light emitted from the semiconductor light emitting element toward one surface of the phosphor;
A projection lens that projects visible light emitted from the phosphor to the front of the vehicle;
In a vehicle lamp comprising:
The projection lens has a focal point located in the vicinity of the phosphor, and has a diffusing portion that diffuses the excitation light incident on the projection lens from the phosphor, and faces the other surface of the phosphor. Arranged so that
The diffusing portion is formed by performing uneven processing on a portion of the projection lens that is irradiated with the excitation light condensed by the condensing optical system and transmitted through the phosphor. A vehicular lamp characterized by the above . The vehicular lamp according to claim 1, wherein the semiconductor light emitting element emits laser light .

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