Optical element and optical device

Patent metadata

Field	Value
Publication number	US-9864111-B2
Application number	US-201414514985-A
Country	US
Kind code	B2
Filing date	Oct 15, 2014
Priority date	Nov 20, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

An optical element of an embodiment includes an optical element made of a material transparent to light, the optical element including: a back surface facing the front surface; and a connection surface. The front surface includes a recessed surface in a region facing the connection surface. The recessed surface has a point closest to the connection surface as a closest point, and has a first singular point other than the closest point.

First claim

What is claimed is:

1. A light receiving optical element made of a material transparent to light, the optical element comprising:
a front surface having a first surface, a second surface and a third surface;
a back surface facing the front surface; and
a fourth surface connecting to the third surface,
wherein the front surface includes a recessed surface in a region facing the fourth surface,
the recessed surface includes the second surface and the third surface,
the recessed surface has a point closest to the fourth surface as a closest point, and has a first singular point being a discontinuous slope point other than the closest point,
the second surface is situated between the first surface and the third surface,
the first singular point is a boundary point between the second surface and the third surface,
the back surface has a fifth surface and a sixth surface,
a second singular point being a discontinuous slope point is included in the back surface,
the second singular point is a boundary point between the fifth surface and the sixth surface,
the fifth surface is connected to the front surface, and
the sixth surface is situated on the side of the fourth surface,
wherein rays are incident from the first surface,
the rays being incident from the first surface are reflected on the fifth surface and the sixth surface,
the rays being reflected on the fifth surface are reflected on the second surface,
a portion of the rays being reflected on the second surface are reflected on the third surface,
a portion of the rays being reflected on the second surface are introduced into the fourth surface,
the rays being reflected on the sixth surface are reflected on the third surface, and
the rays being reflected on the third surface are introduced into the fourth surface.

2. The light receiving optical element according to claim 1 , wherein the back surface includes a reflection surface subjected to reflection coating, or includes a reflection surface being physically in contact with the back surface.

3. The light receiving optical element according to claim 1 , wherein the recessed surface of the front surface includes a reflection surface subjected to reflection coating from the first singular point to the closest point, or includes a reflection surface being physically in contact with the recessed surface.

4. The light receiving optical element according to claim 1 , wherein a through hole is provided from the front surface to the back surface.

5. The light receiving optical element according to claim 1 , wherein a first point is taken in the fourth surface,
a distance of a line connecting the first point and the first singular point is a first distance,
a point having a distance from the first point larger than the first distance is a second point in the recessed surface, and
an angle θ 1 made by a normal line in the second point and a line from the second point to the first point satisfies an (expression 1):

θ
1

≥

sin

-
1

⁡

(

1
n

)

,

(

Expression
⁢

⁢
1

)

where the refractive index of the optical element is n.

6. The light receiving optical element according to claim 5 , wherein a first point is taken in the fourth surface,
a distance of a line connecting the first point and the first singular point is a first distance,
a point having a distance from the first point smaller than the first distance is a third point in the recessed surface, and
an angle θ 2 made by a normal line in the third point and a line from the third point to the first point satisfies an (expression 2):

θ
2

<

sin

-
1

⁡

(

1
n

)

,

(

Expression
⁢

⁢
2

)

where the refractive index of the optical element is n.

7. The light receiving optical element according to claim 1 , wherein an orthogonal point is included in the fourth surface, and
the orthogonal point is a point that a perpendicular line from the first singular point to the fourth surface and the fourth surface cross each other at a right angle.

8. The light receiving optical element according to claim 1 , wherein, among normal lines in points on the recessed surface,
a normal line that becomes parallel to the fourth surface exists.

9. The light receiving optical element according to claim 1 , wherein a plane is included in the front surface.

10. The light receiving optical element according to claim 6 , wherein a fourth point is taken in the recessed surface,
a normal line in the fourth point is perpendicular to the fourth surface, and
an angle θ 3 made by a line connecting the fourth point and the second singular point, and the normal line in the fourth point satisfies an (expression 3):

θ
3

≥

sin

-
1

⁡

(

1
n

Assignees

• Toshiba Kk

Inventors

• Ohno Hiroshi
• Yamamoto Kazushige
• Shibasaki Soichiro

Classifications

• Y10T428/24322

  Composite web or sheet · CPC title

• Y10T428/24612

  Composite web or sheet · CPC title

• Y10T428/24479

  including variation in thickness · CPC title

• G02B19/0042

  for use with direct solar radiation · CPC title

• G02B19/0028

  refractive and reflective surfaces, e.g. non-imaging catadioptric systems · CPC title