Capsule endoscope

• US 20030171648A1
• Filed: 01/21/2003
• Published: 09/11/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Matsumoto, Shinya, Hasegawa, Akira, Takizawa, Hironobu, Suzuki, Takayuki, Segawa, Hidetake, Yokoi, Takeshi
• Granted Patent: US 6,939,295 B2
• Time in Patent Office: Days
• US Class Current: 600/109
• CPC Class Codes: A61B 1/04 combined with photographic or television appliances
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging

Abstract

A capsule endoscope is disclosed having an illumination means, an imaging system that includes an objective optical system, and a transparent cover. The invention is characterized by one of: (1) the transparent cover has a larger radius of curvature in a central region of the field of view of the objective optical system than the radius of curvature of the transparent cover in a peripheral region of the field of view of the objective optical system, or (2) the imaging system has a different near point of focus distance for a central region of the field of view than the near point of focus distance of a region that is peripheral to the central region of the field of view and the objective optical system includes a meniscus lens element of positive refractive power and a plano-convex lens element.

Claims

1. A capsule endoscope comprising:

an illumination means;

an imaging system that includes an objective optical system; and

a transparent cover which has a larger radius of curvature in a central region of the field of view of the objective optical system than the radius of curvature of the transparent cover in a peripheral region of the field of view.

2. The capsule endoscope as set forth in claim 1, and further comprising:

an image sensor; and

a transmitter which transmits electromagnetic signals containing data output by the image sensor.

3. The capsule endoscope as set forth in claim 1, wherein the transparent cover includes a central region of the field of view that is planar, and the transparent cover satisfies the following condition in a peripheral region of the field of view

1≦

r≦

5

where is the radius of curvature of a surface of the transparent cover, in mm.

4. The capsule endoscope as set forth in claim 1, wherein a central region of the field of view of the objective optical system has a different depth of field than the field of view of the objective optical system outside the central region.

5. The capsule endoscope as set forth in claim 4, wherein the near point position of the depth of field of the objective optical system within the central region is larger than the near point position of the depth of field of the objective optical system outside the central region.

6. A capsule endoscope, comprising:

an illumination means;

an imaging system that includes an objective optical system having a different near point distance for a central region of the field of view than the near point distance of the region that is peripheral to the central region of the field of view; and

a transparent cover;

wherein

the objective optical system includes a meniscus lens element of positive refractive power and a plano-convex lens element.

7. The capsule endoscope as set forth in claim 6, wherein the field of view of the objective optical system is in the range from 90°

to 140°

.

8. The capsule endoscope as set forth in claim 7, wherein lens elements of the objective optical system are made by injection molding of plastic.

9. A capsule endoscope comprising:

an illumination source;

an imaging system that includes an objective optical system; and

a transparent cover;

wherein

the transparent cover has a larger radius of curvature in a central region of the field of view of the objective optical system than the radius of curvature of the transparent cover in a peripheral region of the field of view of the objective optical system, or

the imaging system has a different near point distance for a central region of the field of view than the near point distance of a region that is peripheral to the central region of the field of view, and the objective optical system includes a meniscus lens element of positive refractive power and a plano-convex lens element.