Endoscope system

• US 6,582,362 B2
• Filed: 07/13/2001
• Issued: 06/24/2003
• Est. Priority Date: 07/14/2000
• Status: Active Grant

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Konno, Mitsujiro
• Primary Examiner(s): MULCAHY, JOHN M
• Application Number:
  US09/903,866
• Publication Number:
  US 20020055669A1
• Time in Patent Office: 711 Days
• Field of Search: 600/112, 600/162, 600/167, 600/168, 348/65, 359/656-661, 359/368, 359/379, 359/380
• US Class Current: 600/167
• CPC Class Codes: A61B 1/00188 with focusing or zooming features
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• CPC Class Codes: A61B 1/051 Details of CCD assembly

Abstract

An endoscope system in which a normal observation image and a near observation image are photographed by a solid-state image sensor upon operation of a focus adjustment device for changing a focal length and a working distance satisfies:

WD_Wide>WDtele

f_wide≧f_tele

where f_wide is a focal length in a normal observation mode, WD_wide is a working distance in the normal observation mode, f_tele is a focal length in a near observation mode, and WD_tele is a working distance in the near observation mode. Whereby, the endoscope system is provided with a wide depth of field so as to allow even a person without considerable skills to easily manipulate the system in the magnifying observation mode, is able to improve accuracy of diagnosis information by enhancing seeming resolution of the magnified information, and is able to improve accuracy of diagnosis by facilitating discussion among a plurality of medical doctors.

Claims

1. An endoscope system which is adjustable to a plurality of object distances and which is provided with a photographing optical system to display an image for magnifying observation, comprising:

an optical system which allows switching between a normal observation image and a near observation image by operation of a focus adjustment device for changing a focal length and a working distance;

a solid-state image sensor which photographs an image formed by said optical system;

an image display unit which displays the image;

an image control device which generates an image to be displayed on said image display unit on the basis of information from said solid-state image sensor and which controls switching between image processing modes;

a calculating device which calculates optical amounts representing a situation of said optical system; and

an optical system control device which controls said optical system;

wherein in operation of said focus adjustment device, the following conditions are satisfied;

2. An endoscope system in which a normal observation image and a near observation image are photographed by a solid-state image sensor upon operation of a focus adjustment device for changing a focal length and a working distance,

wherein the following conditions are satisfied:

 

WD_wide>

WD_tele

3. An endoscope system according to claim 2, further comprising a light adjustment device for maintaining a constant brightness of an image on said display unit, which image varies in accordance with change of the working distance associated with operation of said focus adjustment device.

5. An endoscope system according to claim 2 or 4, wherein the following condition is satisfied:

6. An endoscope system according to claim 5, further satisfying the following conditions:

7. An endoscope system according to claim 6, further comprising a control device that supplies a control signal to said focus adjustment device on the basis of a signal from said solid-state image sensor, wherein switching control of image processing modes in accordance with a situation of the optical system is performed on the basis of said control signal.

8. An endoscope system according to claim 5, further satisfying the following conditions:

9. An endoscope system according to claim 8, further comprising a control device that supplies a control signal to said focus adjustment device on the basis of a signal from said solid-state image sensor, wherein switching control of image processing modes in accordance with a situation of the optical system is performed on the basis of said control signal.

10. An endoscope system according to claim 2 or 4, wherein the following condition is satisfied:

11. An endoscope system according to claim 2, 3 or 4, further comprising a control device that sets, at least in the near observation mode, a ratio of an amount of possible image information α

appearing on said solid-state image sensor to an amount of image information β

displayed on said display unit to be α

/β

≧

1.

12. An endoscope system according to claim 11, wherein said calculating device performs re-calculation upon a value of α

/β

which is set by said image control device as calculating the optical amounts being fed back.

13. An endoscope system according to claim 11, wherein said control device is configured to prevent degraded video on a marginal portion of the image in the near observation mode to be displayed.

14. An endoscope system according to claim 13, wherein a center position w1 of the image information displayed on said image display unit corresponds to a point existing in a central area 25% of the possible image information on said solid-state image sensor.

15. An endoscope system according to claim 11, wherein a center position w1 of the image information displayed on said image display unit corresponds to a point existing in a central area 25% of the possible image information on said solid-state image sensor.

16. An endoscope system according to claim 2, 3 or 4, further satisfying the following condition:

17. An endoscope system according to claim 2, 3 or 4, further satisfying the following condition:

18. An endoscope system according to claim 2, 3 or 4, wherein an effective aperture diameter ratio F_no is variable in such a range that a value in said range is equal to or smaller than a diffraction limit.

19. An endoscope system according to claim 18, wherein the following condition is satisfied:

4. An endoscope system in which a normal observation image and a near observation image are photographed by a solid-state image sensor upon operation of a focus adjustment device for changing a focal length and a working distance,

wherein the following conditions are satisfied: