Optical element, extended optical element comprising optical element, and lamp housing

1. An optical element comprising:

a polygonal column-shaped transparent body which has four inner wall surfaces that surround a rectangular column-shaped space having a square-shaped opening when seen in a plan view, four outer wall surfaces that are respectively parallel to the inner wall surfaces, two outer wall surfaces which are perpendicular to a diagonal line of the square-shaped opening, the two outer wall surfaces facing each other, and two side wall surfaces that are perpendicularly connected to at least one of the two outer wall surfaces and are connected to at least one of the four outer wall surfaces,

wherein, in the transparent body, a distance between the two outer wall surfaces facing each other is longer than the diagonal line,

wherein light perpendicularly incident on one outer wall surface of the two outer wall surfaces facing each other undergoes repetitive total reflection on the inner wall surfaces and the outer wall surfaces and, finally, exits along almost the same axis as a light axis of light incident through the other outer wall surface of the two outer wall surfaces facing each other, and

wherein a cuboid-shaped protrusion portion formed by the two side wall surfaces and the one of the two outer wall surfaces does not contribute to path changes caused by the total reflection of light.

2. The optical element according to claim 1 ,

wherein a refractive index is 1.41 or higher.

3. The optical element according to claim 1 which consists of any one of acryl, polycarbonate, cycloolefin-based resin, and glass or a mixture of two or more of these materials.

4. The optical element according to claim 1 , further comprising:

a screen that covers side surfaces other than the two outer wall surfaces facing each other.

5. A lamp housing comprising:

an optical element comprising:

a polygonal column-shaped transparent body which has four inner wall surfaces that surround a rectangular column-shaped space having a square-shaped opening when seen in a plan view, four outer wall surfaces that are respectively parallel to the inner wall surfaces, two outer wall surfaces which are perpendicular to a diagonal line of the square-shaped opening, the two outer wall surfaces facing each other, and two side wall surfaces that are perpendicularly connected to at least one of the two outer wall surfaces and are connected to at least one of the four outer wall surfaces,

wherein, in the transparent body, a distance between the two outer wall surfaces facing each other is longer than the diagonal line, and

wherein light perpendicularly incident on one outer wall surface of the two outer wall surfaces facing each other undergoes repetitive total reflection on the inner wall surfaces and the outer wall surfaces and, finally, exits along almost the same axis as a light axis of light incident through the other outer wall surface of the two outer wall surfaces facing each other, and

a lamp disposed in a rectangular column-shaped space surrounded by the four inner walls of the optical element.

6. The lamp housing according to claim 5 , further comprising:

a reflection plate having an arc sectional shape which reflects light from the lamp in the rectangular column-shaped space of the optical element.

7. The lamp housing according to claim 5 , further comprising:

a reflection plate that covers at least a part of the four outer wall surfaces of the optical element and/or a diffusion plate.

8. The lamp housing according to claim 5 , further comprising:

a reflection plate that covers a top surface of the optical element.

9. An optical element comprising:

a main body portion formed by connecting two prismatic bodies having parallelogram-shaped bottom surfaces having inner angles of 45° and 135° using one side surface of each of the two prismatic bodies as a connection surface so that the 45° inner angles and the 135° inner angles of the respective parallelogram-shaped bottom surfaces come close to each other; and

at least one cuboid-shaped protrusion portion which protrudes outside from a surface facing the connection surface of the main body portion and has a surface parallel to the surface facing the connection surface;

wherein the main body portion and the at least one cuboid-shaped protrusion portion have an integrated structure.

10. The optical element according to claim 9 ,

wherein the two prismatic bodies have the same shape.

11. An optical element comprising:

a polygonal column-shaped transparent body which has four inner wall surfaces that surround a rectangular column-shaped space having a square-shaped opening when seen in a plan view, four outer wall surfaces that are respectively parallel to the inner wall surfaces, two outer wall surfaces which are perpendicular to a diagonal line of the square-shaped opening, the two outer wall surfaces facing each other, and two side wall surfaces that are perpendicularly connected to at least one of the two outer wall surfaces and are connected to at least one of the four outer wall surfaces,

wherein, in the transparent body, a distance between the two outer wall surfaces facing each other is longer than the diagonal line, and

light perpendicularly incident on one outer wall surface of the two outer wall surfaces facing each other undergoes repetitive total reflection on the inner wall surfaces and the outer wall surfaces and, finally, exits along almost the same axis as a light axis of light incident through the other outer wall surface of the two outer wall surfaces facing each other which is constituted by bringing the protrusion portions close to each other so that two optical elements, each of which according to claim 10 , are symmetrically disposed and combined together.

12. An extended optical element which is formed by combining one or more optical elements according to claim 10 with the optical element comprising:

a polygonal column-shaped transparent body which has four inner wall surfaces that surround a rectangular column-shaped space having a square-shaped opening when seen in a plan view, four outer wall surfaces that are respectively parallel to the inner wall surfaces, two outer wall surfaces which are perpendicular to a diagonal line of the square-shaped opening, the two outer wall surfaces facing each other, and two side wall surfaces that are perpendicularly connected to at least one of the two outer wall surfaces and are connected to at least one of the four outer wall surfaces,

wherein, in the transparent body, a distance between the two outer wall surfaces facing each other is longer than the diagonal line, and

light perpendicularly incident on one outer wall surface of the two outer wall surfaces facing each other undergoes repetitive total reflection on the inner wall surfaces and the outer wall surfaces and, finally, exits along almost the same axis as a light axis of light incident through the other outer wall surface of the two outer wall surfaces facing each other, whereby one outer wall surface and the other outer wall surface of the two outer wall surfaces facing each other are extended.

13. An optical element which is formed by disposing two prismatic bodies having parallelogram-shaped bottom surfaces having inner angles of 45° and 135° so that, when seen in a plan view, one of two sides of one prismatic body which constitute the 45° inner angle is brought into contact with the corresponding side of the other prismatic body so as to form an angle of 90° and connecting side surfaces of the two prismatic bodies as a single surface to one surface of a parallel plate;

wherein the two prismatic bodies and a parallel plate have an integrated structure.

14. The optical element according to claim 13 ,

wherein the two prismatic bodies have the same shape.

15. An optical element comprising:

a polygonal column-shaped transparent body which has four inner wall surfaces that surround a rectangular column-shaped space having a square-shaped opening when seen in a plan view, four outer wall surfaces that are respectively parallel to the inner wall surfaces, two outer wall surfaces which are perpendicular to a diagonal line of the square-shaped opening, the two outer wall surfaces facing each other, and two side wall surfaces that are perpendicularly connected to at least one of the two outer wall surfaces and are connected to at least one of the four outer wall surfaces,

wherein, in the transparent body, a distance between the two outer wall surfaces facing each other is longer than the diagonal line, and

light perpendicularly incident on one outer wall surface of the two outer wall surfaces facing each other undergoes repetitive total reflection on the inner wall surfaces and the outer wall surfaces and, finally, exits along almost the same axis as a light axis of light incident through the other outer wall surface of the two outer wall surfaces facing each other which is constituted by symmetrically disposing two optical elements, each of which according to claim 14 , so that side surfaces facing the other side surfaces of the prismatic bodies face each other.