Vehicle-purpose lighting tool

• US 20080291685A1
• Filed: 05/21/2008
• Published: 11/27/2008
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Misawa, Akihiro, Oba, Tatsuya, Arakawa, Tetsuya
• Granted Patent: US 7,815,345 B2
• Time in Patent Office: Days
• US Class Current: 362/459
• CPC Class Codes: B60Q 1/2696 Mounting of devices using LEDs
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21S 43/237 rod-shaped
• CPC Class Codes: F21S 43/241 of complex shape
• CPC Class Codes: F21S 43/249 with two or more light sources being coupled into the light guide
• CPC Class Codes: F21S 43/315 using total internal reflection
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A vehicle-purpose lighting tool is featured by comprising: a light-conducting member having a front light-emitting plane, a rear plane having a concave/convex shape, and a side edge plane; and a light source arranged at a position opposite to the side edge plane; in which within external light which is entered via the front light-emitting plane into the light-conducting member, a portion of the external light which is directly traveled to the side edge plane is totally reflected on a boundary plane of the side edge plane portion; a plurality of reflecting portions are formed on the rear plane and are coupled to each other via a coupling portion in such a direction that the reflecting portions are separated apart from the side edge plane side; and distances between the plurality of reflecting portions and the front light-emitting plane are changed in a discontinuous manner along the separating direction.

Claims

1. A vehicle-purpose lighting tool comprising:

a light-conducting member having a front light-emitting plane, a rear plane having a concave/convex shape, and a side edge plane; and

a light source arranged at a position opposite to the side edge plane;

wherein;

within external light which is entered via the front light-emitting plane into the light-conducting member, a portion of the external light which is directly traveled to the side edge plane is totally reflected on a boundary plane of the side edge plane portion;

a plurality of reflecting portions are formed on the rear plane and are coupled to each other via a coupling portion in such a direction that the reflecting portions are separated apart from the side edge plane side; and

distances between the plurality of reflecting portions and the front light-emitting plane are changed in a discontinuous manner along the separating direction.

2. The vehicle-purpose lighting tool as claimed in claim 1 wherein:

a reflecting treatment is not performed with respect to said coupling portion.

3. The vehicle-purpose lighting tool as claimed in claim 1, wherein:

an angle “

θ

”

defined between a plane defined by the reflecting portions and the side edge plane, another angle “

θ

₁”

defined between the front light-emitting plane and the side edge plane, an incident angle “

θ

₂”

of the light of the light source with respect to the side edge plane, and a refractive index “

n”

of the light-conducting member can satisfy the below-mentioned relative equation;

θ

=[180°

−

θ

₁−

sin<sup>−

1</sup>{sin(90°

−

θ

₁/n)+sin<sup>−

1</sup>{(sin θ

₂)/n}}/2

4. The vehicle-purpose lighting tool as claimed in claim 1 wherein:

when images of said reflecting portions are projected by light along a direction of an optical axis of said light source with respect to a plane located parallel to said side edge plane, respective projection images of said reflecting portions are not overlapped with each other.

5. The vehicle-purpose lighting tool as claimed in claim 1 wherein:

a gap is not essentially produced between said projection images adjacent to each other.

6. The vehicle-purpose lighting tool as claimed in claim 1, wherein:

said coupling portion is provided with a plane which totally reflects thereon the external light entered via said front light-emitting plane into said light-conducting member, or another plane which passes therethrough said external light so as to re-enter the passed external light from said coupling portion into said light-conducting member.

7. The vehicle-purpose lighting tool as claimed in claim 1, wherein:

said light source is an LED (Light-emitting Diode) lamp.