Abstract:
An imaging unit provided at a tip portion of an endoscope includes: an imaging element configured to receive light and perform photoelectric conversion on the light to generate an electrical signal; an oscillator configured to generate a clock signal for driving the imaging element; a photoelectric element configured to convert the electrical signal generated by the imaging element into an optical signal and to output the optical signal to outside; a regulator configured to convert electric power input from the outside into electric power depending on each of the imaging element, the oscillator, and the photoelectric element, and to supply the converted electric power thereto. The imaging element is spaced farther than the oscillator and the photoelectric element from the regulator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of PCT international application Ser. No. PCT/JP2014/077526 filed on Oct. 16, 2014 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Application No. 2014-031767, filed on Feb. 21, 2014, incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The disclosure relates to an imaging unit provided at a tip of an insertion unit of an endoscope that is to be inserted into a subject for imaging inside of the subject. 
         [0004]    2. Related Art 
         [0005]    Conventionally, in the medical field and the industrial field, endoscopes have been used widely in a variety of examinations. Among them, a medical endoscope obtains an in-vivo image of inside of a body cavity of the subject by inserting a flexible insertion unit having an elongated shape and provided with an imaging element at a tip thereof into the body cavity of the subject such as a patient. 
         [0006]    There has been known a technique in which an imaging unit is provided at a tip portion of such endoscope. The imaging unit includes a circuit board on which an imaging element, electronic components such as a capacitor and an IC chip constituting a driving circuit for driving the imaging element, and a regulator for supplying electric power to each of the electronic components are mounted (see Japanese Patent Application Laid-open No. 2003-52628). 
       SUMMARY 
       [0007]    In some embodiments, an imaging unit provided at a tip portion of an endoscope includes: an imaging element configured to receive light and perform photoelectric conversion on the light to generate an electrical signal; an oscillator configured to generate a clock signal for driving the imaging element; a photoelectric element configured to convert the electrical signal generated by the imaging element into an optical signal and to output the optical signal to outside; a regulator configured to convert electric power input from the outside into electric power depending on each of the imaging element, the oscillator, and the photoelectric element, and to supply the converted electric power thereto. The imaging element is spaced farther than the oscillator and the photoelectric element from the regulator. 
         [0008]    The above and other features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic view illustrating a configuration of an endoscope system according to one embodiment of the present invention; and 
           [0010]      FIG. 2  is a partial sectional view of a tip portion of an endoscope in the endoscope system according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Modes for carrying out the present invention (hereinafter referred to as “embodiment(s)”) will be described below. In this embodiment, as an example of an imaging system, reference will be made to a medical endoscope system for imaging and displaying an image inside of a body cavity of a subject such as a patient. Note that the present invention is not to be limited by the embodiments below. The same reference signs are used to designate the same elements throughout the drawings. 
         [0012]      FIG. 1  is a schematic view illustrating a configuration of an endoscope system according to one embodiment of the present invention. An endoscope system  1  illustrated in  FIG. 1  includes an endoscope  2  that images an in-vivo image of the subject by inserting a tip portion thereof into the body cavity of the subject, a light source device  3  that generates illumination light to be emitted from a tip of the endoscope  2 , a processing device  4  (control device) that performs predetermined image processing on the in-vivo image imaged by the endoscope  2  as well as totally controls operation of the endoscope system  1  as a whole, and a display device  5  that displays the in-vivo image on which the image processing has been performed by the processing device  4 . 
         [0013]    First, a configuration of the endoscope  2  will be described. The endoscope  2  includes an flexible insertion unit  21  having a thin elongated shape, an operating unit  22  connected to a proximal end side of the insertion unit  21  and that receives input of various operation signals, and a universal code  23  extending from the operating unit  22  to a direction different from a direction in which the insertion unit  21  extends and incorporating various cables that connect to the light source device  3  and the processing device  4 . 
         [0014]    The insertion unit  21  includes a tip portion  24  incorporating an imaging element (imaging device) in which a picture element, which generates a signal by receiving light and performing photoelectric conversion, is two-dimensionally arranged, a bendable bent portion  25  including a plurality of bent pieces, and a long flexible pipe portion  26  connected with a proximal end side of the bent portion  25 . 
         [0015]    The operating unit  22  includes a bent knob  221  that bends the bent portion  25  in a vertical direction and a horizontal direction, a treatment tool insertion unit  222  through which a treatment tool such as a biological forceps, an electric knife, and an inspection probe are configured to be inserted into the body cavity of the subject, and a plurality of switches  223  that is an operating input unit for inputting an operating instruction signal of a peripheral device such as an air feed means, a water feed means, and an image display control in addition to the processing device  4  and the light source device  3 . The treatment tool, which is inserted through the treatment tool insertion unit  222 , appears from an opening portion (not illustrated) after going through a treatment tool channel (not illustrated) of the tip portion  24 . 
         [0016]    The universal code  23  has at least a light guide (not illustrated) for transmitting the illumination light from the light source device  3 , and a plurality of signal lines for transmitting a clock signal, a synchronizing signal, and the like for driving the imaging element provided at the tip portion  24  from the processing device  4 . 
         [0017]    Next, a configuration of the tip portion  24  of the endoscope  2  will be described in detail.  FIG. 2  is a partial sectional view of the tip portion  24  of the endoscope  2 . 
         [0018]    As illustrated in  FIG. 2 , the tip portion  24  has an imaging unit  240  therein. The imaging unit  240  includes an optical system  241  that forms an image of the object, an imaging element  242  that generates an image signal (image data) of the object by receiving the image of the object that has been formed by the optical system  241  and by performing photoelectric conversion thereon, an oscillator  243  that emits a signal for driving the imaging element  242 , a photoelectric element  244  that outputs the image signal that has been generated by the imaging element  242  to the processing device  4 , a regulator  245  that supplies electric power to each of components of the imaging unit  240 , and a flexible printed circuit board  246  (hereinafter, referred to as “FPC board  246 ”) on which the oscillator  243 , the photoelectric element  244 , and the regulator  245  are disposed. 
         [0019]    The optical system  241  includes a plurality of objective lenses L 1  to L 4  and forms the image of the object that is irradiated with the illumination light from the light source device  3 . Note that the optical system  241  may include a crossed prism, a condenser lens, a collimator lens, and the like. 
         [0020]    The imaging element  242  is arranged to an image formation position in which the image of the object is formed by the optical system  241 , and the imaging element  242  generates an image signal of the object by receiving the image of the object, which is formed by the optical system  241 , and by performing photoelectric conversion thereon. The imaging element  242  outputs this image signal to the photoelectric element  244 . The imaging element  242  includes a solid imaging element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging element  242  generates the image signal based on the clock signal that is output from the oscillator  243 , and outputs the generated image signal to the photoelectric element  244 . Inside the tip portion  24 , the imaging element  242  is positioned farther than the oscillator  243  and the photoelectric element  244  from the regulator  245 . 
         [0021]    The oscillator  243  generates the clock signal for driving the imaging element  242 . The oscillator  243  is disposed on an upper surface of the FPC board  246 . Inside the tip portion  24 , the oscillator  243  is positioned farther than the photoelectric element  244  from the regulator  245 . 
         [0022]    The photoelectric element  244  converts the image signal (electrical signal) that has been output from the imaging element  242  into an optical signal, and the optical signal that has been converted is output to the processing device  4 . A cable connecting the photoelectric element  244  with the processing device  4  includes an optical fiber and the like. 
         [0023]    The regulator  245  converts electric power that is supplied from the processing device  4  through the universal code  23  into electric power useable by each of the imaging element  242 , the oscillator  243 , and the photoelectric element  244  and supplies this converted electric power to each of the components. The regulator  245  is disposed on a back surface of the FPC board  246 . 
         [0024]    In the imaging unit  240  having such configuration, considering an influence of heat, the optical system  241 , the imaging element  242 , the oscillator  243 , the photoelectric element  244 , and the regulator  245  are arranged in this order from an end of the tip portion  24 . Specifically, in the imaging unit  240 , the imaging element  242 , the oscillator  243 , and the photoelectric element  244  are spaced from the regulator  245  in this order. For example, in the imaging unit  240 , when a distance between the imaging element  242  and the regulator  245  is denoted by D 1 , a distance between the oscillator  243  and the regulator  245  is denoted by D 2 , and a distance between the photoelectric element  244  and the regulator  245  is denoted by D 3 , D 1 &gt;D 2 &gt;D 3  is satisfied. 
         [0025]    According to one embodiment of the present invention described above, the optical system  241 , the imaging element  242 , the oscillator  243 , the photoelectric element  244 , and the regulator  245  are arranged in this order from the end of the tip portion  24 . The regulator  245  having the largest heating value is positioned inside the tip portion  24  farthest from the imaging element  242  which is the most affected by heat. Thus even when temperature of the tip portion  24  or temperature of the regulator  245  is increased, it is possible to reduce noise that occurs in the image signal generated by the imaging element  242 . 
         [0026]    According to some embodiments, it is possible to reduce noise that occurs in the image signal generated by the imaging element. 
         [0027]    In this way, the present invention may include various embodiments not described herein, and it is possible to add various design changes and the like within a scope of technical ideas specified by claims. 
         [0028]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.