Electronic-endoscope light source unit for setting shading period

• US 20010037052A1
• Filed: 07/05/2001
• Published: 11/01/2001
• Est. Priority Date: 03/25/1998
• Status: Active Grant

• Current Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Inventors: Yamanaka, Kazuhiro, Higuchi, Mitsuru, Takeuchi, Shinji, Ayame, Daisuke
• Granted Patent: US 6,413,211 B2
• Time in Patent Office: Days
• US Class Current: 600/178
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

The present invention is a unit for eliminating the fluctuation of luminous energy reduction by keeping the response time of a shading mechanism constant even if a diaphragm opening degree differs when reading every pixel by setting a shading period. This unit is provided with a shading mask having a quadrangular or V-shaped opening and moves a shading shutter in the horizontal direction perpendicular to the vertically moving direction of a diaphragm plate. Therefore, a shading period is set in accordance with the constant response time of the shading shutter and the rate of luminous energy reduction becomes constant. Moreover, a high-quality static image having a stable brightness can be obtained by reading the signal of every pixel obtained by a CCD through one-time exposure while using the shading period and then pixel-mixing signals. Furthermore, it is possible to use the Archimedean spiral for the outer periphery of the diaphragm plate or the shading shutter.

Claims

1. An electronic-endoscope light source unit for setting a shading period, comprising:

first shading means for shading a light-source luminous flux in a predetermined shading direction; and

second shading means for shading the light-source luminous flux in a shading direction almost perpendicular to the shading direction of the first shading means, wherein one of the first shading means and the second shading means is used as a diaphragming mechanism and the other shading means is used as a fully-closed shading mechanism for setting a fully-closed shading period for reading the signal of every pixel accumulated in an image pickup device.

2. The electronic-endoscope light source unit for setting a shading period according to

claim 1

, wherein a shading mask having a quadrangular opening is set, and the diaphragm member of the diaphragming mechanism is made to move along the top and bottom sides or the right and left sides of the quadrangular opening, and the shading shutter of the fully-closed shading mechanism is moved along the other two sides.

3. The electronic-endoscope light source unit for setting a shading period according to

claim 1

, wherein the second shading means has a shading member whose outer periphery is formed like the Archimedean spiral and the outer periphery of the shading member is made to move in a direction almost perpendicular to the shading direction of the first shading means so as to shade the light-source luminous flux.

4. The electronic-endoscope light source unit according to

claim 1

, wherein the electronic-endoscope light source unit is applied to an electronic endoscope having an image-pickup-device driving circuit for reading the signal of every pixel accumulated in a solid-state image pickup device by using a shading period to set the shading period by the fully-closed shading mechanism.

5. The electronic-endoscope light source unit according to

claim 4

, wherein the image-pickup-device driving circuit executes the under-image-pickup-device-outputting pixel-mixing read mode for outputting video signals accumulated in an image pickup device by mixing them between upper and lower lines to form a dynamic image and the every-pixel read mode for reading the signal of every pixel accumulated in the image pickup device through one-time exposure by using the shading period to form a static image.

6. An electronic-endoscope light source unit for setting a shading period, comprising:

a shading mask for controlling the passing range of a light-source luminous flux by its almost-V-shaped opening;

first shading means provided with a shading member to be rotated about the V-shape intersection of the opening of the shading mask to shade the V-shaped opening in accordance with the rotation of the shading member; and

second shading means provided with a shading member to be moved in a direction almost perpendicular to the rotational direction of the shading member of the first shading means to shade the V-shaped opening by the shading member;

wherein one of the first shading means and the second shading means is used as a diaphragming mechanism and the other shading means is used as a fully-closed shading mechanism for setting a fully-closed shading period for reading the signal of every pixel accumulated in an image pickup device.

7. The electronic-endoscope light source unit for setting a shading period according to

claim 6

, wherein the first shading means is used as the fully-closed shading mechanism and the second shading means is used as the diaphragming mechanism.

8. The electronic-endoscope light source unit for setting a shading period according to

claim 6

, wherein

a shading member whose outer periphery is formed like the Archimedean spiral is used as the first shading means or second shading means.

9. The electronic-endoscope light source unit according to

claim 6

, wherein the light source unit is applied to an electronic endoscope having an image-pickup-device driving circuit for executing the under-image-pickup-device-outputting pixel-mixing read mode for outputting video signals accumulated in an image pickup device by mixing them between upper and lower lines to form a dynamic image and the every-pixel read mode for reading the signal of every pixel accumulated in the image pickup device through one-time exposure by using the shading period to form a static image and the shading period is set by the fully-closed shading mechanism.