Photographing light quantity controller for endoscope
Inactive Publication Date: 2000-02-22
ASAHI KOGAKU KOGYO KK
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- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
An object of the present invention is to provide a photographing light quantity controller for an endoscope, which is capable of accurate, illuminating light quantity control, even when the brightness of the object is remarkably low.
Problems solved by technology
However, since the output signal (voltage) from the light-receiving element is weak, the output voltage is inputted to a photographing light quantity control circuit after being amplified in an amplifier circuit.
Accordingly, when the object is distant and dark, the voltage that is inputted to the photographing light quantity control circuit is considerably low, so that the voltage value may be inaccurate and the signal processing executed in the photographing light quantity control circuit takes a great deal of time.
Consequently, the illuminating light quantity control cannot accurately be effected.
In particular, a large error may be produced in a control system wherein an exposure time is predicted from the rate of change of the integral value per unit time (differential with respect to time), immediately after the initiation of an exposure operation.
Method used
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Embodiment Construction
Referring to FIG. 1, which shows the whole arrangement of one embodiment of the present invention, reference numeral 1 denotes an endoscope. A camera (photographing device) 2 is detachably attached to an eye-piece 14 of the endoscope 1 through a photographic adapter 3.
Reference numeral 4 denotes a light source apparatus, to which is detachably connected a connector 11 of the endoscope 1. Illuminating light, that is emitted from a light source (lamp) 40, is condensed through a condenser lens 41 so as to be made incident on a light guide fiber bundle 12 in the endoscope 1.
In an illuminating light path, which extends between the light source 40 and the light guide fiber bundle 12, are provided a shutter (light source shutter) 42 which can be opened and closed to fully open and close the illuminating light path, and a variable diaphragm 43 which is capable of varying the area of passage of the illuminating light.
The illuminating light is transmitted through the light guide fiber bundle ...
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A photographing light quantity controller for an endoscope, which is used to control the quantity of illuminating light when a photograph is to be taken through the endoscope. The photographing light quantity controller comprises a device for supplying light for illuminating an object to the endoscope, a device for detecting a quantity of light that is reflected from the object and for outputting a signal in accordance with the detected quantity of light, and a device for amplifying the signal, with the amplifying device having a plurality of amplification factors which can be selected as desired. A photographing light quantity control device is provided for controlling the quantity of illuminating light that is supplied to the endoscope when a photographing operation is conducted, on the basis of the output signal from the amplifying device. A device is also provided for automatically switching over the amplification factors of the amplifying device from one to another in accordance with the brightness of the object.
Description
BACKGROUND OF THE INVENTIONThe present disclosure relates to subject matter contained in Japanese Patent Application No. 2-231361 (filed on Aug. 31, 1990), which is expressly incorporated herein by reference in its entirety.FIELD OF THE INVENTIONThe present invention relates to a photographing light quantity controller for an endoscope, which is used to control the quantity of illuminating light when a photograph is to be taken through the endoscope.Endoscopes are generally designed to be capable of not only observing the inside of a hollow organ in the patient's body but also taking a photograph of it.DESCRIPTION OF THE PRIOR ARTIn a typical conventional photographing light quantity controller for an endoscope, reflected light from an object, that is illuminated by a light source, is received and converted into an electric signal with a light-receiving element. The output of the light-receiving element is integrated to obtain an integral value. When the integral value reaches a pre...
Claims
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Login to View More IPC IPC(8): G02B23/24
CPCG02B23/2469G02B23/2484
InventorFURUYA, KATSUHIKONAKASIMA, MASAAKIENOMOTO, TAKAYUKITAKAHASHI, TADASHI
OwnerASAHI KOGAKU KOGYO KK