Electronic-endoscope light source unit for setting shading period

• US 6,334,845 B1
• Filed: 03/23/1999
• Issued: 01/01/2002
• Est. Priority Date: 03/25/1998
• Status: Expired due to Term

• Current Assignee: Fujinon Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Inventors: Daisuke, Ayame, Shinji, Takeuchi, Yamanaka, Kazuhiro, Higuchi, Mitsuru
• Primary Examiner(s): MULCAHY, JOHN M
• Application Number:
  US09/274,301
• Time in Patent Office: 1,015 Days
• Field of Search: 600/109, 600/160, 600/180, 600/181, 348/22, 348/68, 348/69, 348/220, 348/221, 362/574
• US Class Current: 600/181
• 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:

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.

2. The electronic-endoscope light source unit for setting a shading period according to claim 1, wherein the first shading means is used as the fully-closed shading mechanism and the second shading means is used as the diaphragming mechanism.

3. The electronic-endoscope light source unit for setting a shading period according to claim 1, wherein

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

4. The electronic-endoscope light source unit according to claim 1, 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.