Variable transmittance optical element and imaging optical system including the same arranged at distal end of an endoscope

• US 7,514,667 B2
• Filed: 12/22/2005
• Issued: 04/07/2009
• Est. Priority Date: 12/24/2004
• Status: Expired due to Fees

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Matsumoto, Shinya
• Primary Examiner(s): Sohn; Seung C
• Application Number:
  US11/313,654
• Publication Number:
  US 20060139780A1
• Time in Patent Office: 1,202 Days
• Field of Search: 250/216, 356/450, 356/511, 356/512, 356/513
• US Class Current: 250/216
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• CPC Class Codes: G02B 17/0896 with variable magnification or multiple imaging planes, including multispectral systems systems with only refractive elements G02B15/14
• CPC Class Codes: G02B 23/243 Objectives for endoscopes
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

A variable transmittance optical element is provided in an imaging optical system of an endoscope, and includes small etalons or multiple microscopic mirror that have an effective part that allows passage of a light beam received at a unit light receiving area that corresponds to an individual pixel, or a plurality of pixels, of an image pickup device that is provided in the imaging optical system of the endoscope. Each of said small etalons or microscopic mirrors have facing surfaces that are arranged so as to be parallel to one another on a transparent substrate; and the transparent substrate and an image pickup surface of the image pickup device are positioned so that each of the small etalons or microscopic mirrors allows passage of the light beam.

Claims

1. A variable transmittance optical element that is provided in an imaging optical system of an endoscope, said variable transmittance optical element comprising:

small etalons that have an effective part that allows passage of a light beam received at a unit light receiving area that corresponds to an individual pixel, or a plurality of pixels, of an image pickup device that is provided in the imaging optical system of the endoscope;

each of said small etalons having facing surfaces that are arranged so as to be parallel to one another on a transparent substrate; and

said transparent substrate and an image pickup surface of the image pickup device are positioned so that each of the small etalons allows passage of the light beam to said unit light receiving area.

2. The variable transmittance optical element according to claim 1, wherein:

said small etalons are formed by facing substrates having a size on the order of several μ

m, and a substrate that is farther away from the image pickup surface of the image pickup device has a larger effective part than a substrate that is closer to the image pickup surface of the image pickup device.

3. A variable transmittance optical element that is provided in the imaging optical system of an endoscope, wherein:

said variable transmittance optical element includes multiple microscopic mirrors that have an effective part that allows passage of a light beam that is received at a unit light receiving area corresponding to an individual pixel, or a plurality of pixels, of an image pickup device that is provided in the imaging optical system of the endoscope and said multiple microscopic mirrors are arranged on the facing surfaces of two transparent substrates; and

at least one of the transparent substrates is moved so as to change the mutual distance between the facing microscopic mirrors.

4. The variable transmittance optical element according to claim 3, wherein:

the mutual distance between the facing microscopic mirrors increases from the center to the periphery of the variable transmittance optical element.

5. An endoscope imaging unit;

wherein

an objective lens and a variable transmittance optical element are provided;

said variable transmittance optical element includes small etalons that have an effective part that allows passage of a light beam that is received at a unit light receiving area that corresponds to an individual pixel, or a plurality of pixels, of an image pickup device that is provided in the imaging optical system of an endoscope, said small etalons being arranged on a transparent substrate; and

said transparent substrate and an image pickup surface of the image pickup device are positioned so that each of the small etalons allows passage of the light beam to said unit light receiving area.

6. The endoscope imaging unit according to claim 5, wherein:

said small etalons include small etalons ET1 having a variable peak transmittance wavelength in the wavelength range of 400 nm-600 nm and small etalons ET2 having a variable peak transmittance wavelength in the wavelength range of 600 nm-800 nm; and

images formed by pixels using light which has transmitted through small etalons ET1 and images formed by pixels using light which has transmitted through small etalons ET2 are separately obtained.

7. The endoscope imaging unit according to claim 5, wherein:

said image pickup surface of the image pickup device is divided into multiple image pickup areas;

each image pickup area is provided with an objective lens; and

said small etalons are controlled for each image pickup area.

8. The endoscope imaging unit according to claim 7, wherein the fields of view of the objective lenses overlap.

9. The endoscope imaging unit according to claim 7, wherein:

of the multiple image pickup areas, at least one image pickup area is provided with light that has transmitted through small etalons ET1, each small etalon ET1 having a variable peak transmittance wavelength in the wavelength range of 400 nm-600 nm; and

the other image pickup areas are provided with small etalons ET2, each small etalon ET2 having a variable peak transmittance wavelength in the wavelength range of 600 nm-800 nm; and

images formed at the respective image pickup areas are separately obtained.