Capsule type endoscope

Abstract

A capsule type endoscope includes an illumination device, an imaging device, and a transparent cover covering the illumination device and the imaging device. The imaging device has an objective optical system and an image sensor. When the objective optical system satisfies Condition (1) described below and a white cylinder with a reflectance of 90%, satisfying Condition (3) described below, is observed, illuminance of the imaging surface of the image sensor satisfies Condition (2) described below, in a state where a longitudinal center axis of a capsule coincides with the center axis of the white cylinder with a reflectance of 90%. ω≧50°   (1) T 1 ×0.5≦T 2   (2) D =1.2×Φ   (3) where ω is a half of a field angle of the objective optical system, T 1 is the maximum illuminance in an area on the imaging surface of the image sensor corresponding to a field region of the objective optical system, T 2 is illuminance at a position on the imaging surface of the image sensor corresponding to a half of the maximum image height of the objective optical system, D is the inside diameter of the white cylinder, and Φ is the outside diameter of the capsule type endoscope.

1 - 10 . (canceled) 
     
     
         11 . A capsule type endoscope comprising:
 an illumination system for illuminating an object with narrow-band light;   an imaging system comprising an image sensor and an objective optical system, for imaging the object; and   a transparent cover that covers the illumination system and the imaging system and transmits the narrow-band light emanating from the illumination system and reflected light reflected from the object irradiated with the narrow-band light.   
     
     
         12 . A capsule type endoscope according to  claim 11 , wherein the narrow-band light has a half-value width of 30 nm or less. 
     
     
         13 . A capsule type endoscope according to  claim 11 , wherein the narrow-band light has a peak at least at the wavelength 415 nm. 
     
     
         14 . A capsule type endoscope according to  claim 11 , wherein the illumination system comprises an LED. 
     
     
         15 . A capsule type endoscope according to  claim 11 , wherein the illumination system comprises a laser diode. 
     
     
         16 . A capsule type endoscope according to  claim 11 , wherein the illumination system comprises a white LED and a band-pass filter arranged in front of the white LED. 
     
     
         17 . A capsule type endoscope according to  claim 11 , wherein the illumination system comprises a narrow-band light source for achieving narrow-band illumination and a white light source for achieving white-light illumination. 
     
     
         18 . A capsule type endoscope according to  claim 17 , wherein the white light source comprises a narrow-band light source that emits narrow-band light and a fluorescent body arranged in front of the narrow-band light source. 
     
     
         19 . A capsule type endoscope according to  claim 17 , wherein light-receiving sensitivity of the image sensor is set in such a manner that an image that is obtained by imaging, by the imaging system, of the object as illuminated by the narrow-band light source has a brightness greater than 20% of a brightness of an image that is obtained by imaging, by the imaging system, of the object as illuminated by the white light source. 
     
     
         20 . A capsule type endoscope according to  claim 17 , wherein the narrow-band light source comprises a plurality of narrow-band light source elements and the white light source comprises a plurality of white light source elements, and the narrow-band light source elements and the white light source elements are alternately arranged along a circle surrounding the imaging system. 
     
     
         21 . A capsule type endoscope comprising:
 an illumination system for illuminating an object with narrow-band light; and   an imaging system comprising an image sensor and an objective optical system, for imaging the object;   wherein the narrow-band light has at least one of a half-value width of 30 nm or less and a peak at the wavelength 415 nm.   
     
     
         22 . A capsule type endoscope comprising:
 an illumination system for illuminating an object with illumination light;   an imaging system comprising an image sensor and an objective optical system, for imaging the object;   a narrow-band filter for transmitting, out of reflected light from the object, only wavelengths within narrow-band light, to introduce them onto the image sensor; and   a transparent cover that covers the illumination system and the imaging system and transmits the illumination light emanating from the illumination system and the reflected light.   
     
     
         23 . A capsule type endoscope according to  claim 22 , wherein the narrow-band light has a half-value width of 30 nm or less. 
     
     
         24 . A capsule type endoscope according to  claim 22 , wherein the narrow-band light has a peak at least at the wavelength 415 nm. 
     
     
         25 . A capsule type endoscope according to  claim 22 , wherein the illumination system comprises a white LED. 
     
     
         26 . A capsule type endoscope according to  claim 22 , wherein the narrow-band filter is changed in wavelength to transmit out of the reflected light. 
     
     
         27 . A capsule type endoscope according to  claim 26 , wherein the narrow-band filter is a liquid crystal member that is changed, by a current applied thereto, in wavelength to transmit. 
     
     
         28 . A capsule type endoscope according to  claim 26 , wherein the narrow-band filter has an air space formed between two substrates arranged in parallel, and the air space varies in accordance with a voltage applied to the two substrates. 
     
     
         29 . A capsule type endoscope according to  claim 26 , wherein the narrow-band filter is changed in wavelength to transmit, as synchronized with irradiation with the illumination light by the illumination system. 
     
     
         30 . A capsule type endoscope according to  claim 26 , wherein the narrow-band filter is a hologram filter. 
     
     
         31 . A capsule type endoscope comprising:
 an illumination system for illuminating an object with illumination light;   an imaging system comprising an image sensor and an objective optical system, for imaging the object; and   a narrow-band filter for transmitting, out of reflected light from the object, only wavelengths within narrow-band light, to introduce them onto the image sensor,   wherein the narrow-band light transmitted through the narrow-band filter has at least one of a half-value width of 30 nm or less and a peak at the wavelength 415 nm.   
     
     
         32 . A capsule type endoscope system comprising:
 a capsule type endoscope comprising:
 an illumination system comprising a narrow-band light source, for illuminating an object with narrow-band light emanating from the narrow-band light source; 
 an imaging system comprising an image sensor and an objective optical system, for imaging the object; 
 a transparent cover that covers the illumination system and the imaging system and transmits the narrow-band light and reflected light reflected from the object irradiated with the narrow-band light; and 
 a radio-transmitting unit for radio-transmitting, outside a human body, an image signal picked up by the image sensor; 
   a receiving unit for receiving the image signal radio-transmitted from the radio-transmitting unit of the capsule type endoscope; and   a computer for processing the image signal received by the receiving unit, to cause a display unit to display a corresponding image.   
     
     
         33 . A capsule type endoscope system according to  claim 32 , wherein the narrow-band light has a half-value width of 30 nm or less. 
     
     
         34 . A capsule type endoscope system according to  claim 32 , wherein the narrow-band light has a peak at least at the wavelength 415 nm. 
     
     
         35 . A capsule type endoscope system according to  claim 32 , wherein the illumination system comprises an LED. 
     
     
         36 . A capsule type endoscope system according to  claim 32 , wherein the illumination system comprises a laser diode. 
     
     
         37 . A capsule type endoscope system according to  claim 32 , wherein the narrow-band light source comprises a white LED and a band-pass filter arranged in front of the white LED. 
     
     
         38 . A capsule type endoscope system according to  claim 32 , wherein the illumination system further comprises a white light source for illuminating the object with white light. 
     
     
         39 . A capsule type endoscope system according to  claim 38 , wherein the white light source includes a white LED. 
     
     
         40 . A capsule type endoscope system according to  claim 35 , wherein light-receiving sensitivity of the image sensor is set in such a manner that an image that is obtained by imaging, by the imaging system, of the object as illuminated by the narrow-band light source has a brightness greater than 20% of a brightness of an image that is obtained by imaging, by the imaging system, of the object as illuminated by the white light source. 
     
     
         41 . A capsule type endoscope system according to  claim 38 , wherein the narrow-band light source and the white light source irradiate the object alternately. 
     
     
         42 . A capsule type endoscope system according to  claim 38 , wherein the computer processes the image signal so that a narrow-band light image, which is obtained by imaging of the object illuminated with the narrow-band light, and a white light image, which is obtained by imaging of the object illuminated with the white light, are displayed side by side on the image display unit. 
     
     
         43 . A capsule type endoscope system according to  claim 38 , wherein the computer processes the image signal so that a narrow-band light image, which is obtained by imaging of the object illuminated with the narrow-band light, and a white light image, which is obtained by imaging of the object illuminated with the white light, are alternately displayed on the image display unit. 
     
     
         44 . A capsule type endoscope system according to  claim 32 , wherein the computer is provided with an image analysis circuit for extracting at least one of a region, a stage, and a degree of malignance, of a lesion. 
     
     
         45 . A capsule type endoscope system according to  claim 38 , wherein the computer is provided with an image analysis circuit for extracting at least one of a region, a stage, and a degree of malignance, of a lesion. 
     
     
         46 . A method of observing an inside of a patient's body using a capsule type endoscope, comprising the steps of:
 introducing the capsule type endoscope to the inside of the patient's body;   illuminating an object located inside the patient's body with narrow-band light, upon letting the narrow-band light be transmitted through a transparent dome provided at a distal end of the capsule type endoscope;   entering the narrow-band light as reflected from the object into an imaging system provided in the capsule type endoscope;   generating a narrow-band light image from the narrow-band light incident on the imaging system;   radio-transmitting the narrow-band light image outside the patient's body.   
     
     
         47 . A method of observing an inside of a patient's body using a capsule type endoscope according to  claim 46 , further comprising the steps of:
 illuminating the object inside the patient's body with white light, upon letting the white light be transmitted through the transparent dome provided at the distal end of the capsule type endoscope;   entering the white light as reflected from the object into the imaging system provided in the capsule type endoscope;   generating a white light image from the white light incident on the imaging system;   radio-transmitting the white light image outside the patient's body.   
     
     
         48 . A method of observing an inside of a patient's body using a capsule type endoscope according to  claim 47 ,
 wherein the step of illuminating the object inside the patient's body with narrow-band light and the step of illuminating the object inside the patient's body with white light are alternately repeated.   
     
     
         49 . A method of observing an inside of a patient's body using a capsule type endoscope, comprising the steps of:
 introducing the capsule type endoscope to the inside of the patient's body;   illuminating an object located inside the patient's body with illumination light, upon letting the illumination light be transmitted through a transparent dome provided at a distal end of the capsule type endoscope;   entering narrow-band light, out of reflected light from the object, into an imaging system provided in the capsule type endoscope;   generating a narrow-band light image from the narrow-band light incident on the imaging system; and   radio-transmitting the narrow-band light image outside the patient's body.