Patent Publication Number: US-2015080657-A1

Title: Endoscope fogging prevention unit and endoscope

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2013-193556, filed Sep. 18, 2013, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to an endoscope fogging prevention unit and an endoscope for preventing fogging that occurs in the endoscope. 
     2. Description of the Related Art 
     An insertion section of an endoscope is inserted into a highly humid environment, such as a cavity of the body. When the insertion section is inserted into such the environment and the temperature of the insertion section that has been inserted is lower than the temperature of the environment, fogging may be occur on a surface of an optical member (such as a lens cover) provided at a distal end section of the insertion section because of a difference in temperature. There is the possibility that such fogging may interfere with observation or treatment. 
     In order to deal with the fogging, an endoscope is configured to include a fogging prevention unit provided inside a distal end section of an insertion section and configured to prevent fogging. The fogging prevention unit prevents fogging by heating the interior of the distal end section including an optical member. For that purpose, the fogging prevention unit includes a heater for heating the interior, a temperature sensor for measuring a temperature of the interior, and a substrate on which the heater and the temperature sensor are mounted. 
     An example of the above-described fogging prevention unit is disclosed is Jpn. Pat. Appln. KOKAI Publication No. 2006-282. Jpn. Pat. Appln. KOKAI Publication No. 2006-282 discloses controlling heating by a heater on the basis of a temperature detected by a temperature sensor. 
     BRIEF SUMMARY OF THE INVENTION 
     An aspect of an endoscope fogging prevention unit of the present invention includes: a distal end section including a cylindrical member, in an interior of which at least an optical member is provided; a heating section provided in the interior of the distal end section and configured to heat at least the optical member; a measuring section provided in the interior of the distal end section and configured to measure a temperature of the interior of the distal end section; a wiring substrate section including a mounting area portion in which the heating section and the measuring section are mounted, and a wiring area portion in which a wiring member connected to the heating section and the measuring section is provided; and a conducting section provided in the mounting area portion, having the lowest insulating properties against the outside in the mounting area portion, and connected to a ground of a system different from a system of the wiring member of the heating section and the measuring section. 
     Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  illustrates an interior configuration of a distal end section of an insertion section of an endoscope according to the present invention. 
         FIG. 2  illustrates a configuration of a heating unit. 
         FIG. 3  illustrates Configurations 1 and 2 of an endoscope fogging prevention system according to a first embodiment. 
         FIG. 4A  is a top view of the heating unit. 
         FIG. 4B  is a cross-sectional view cut along line  4 B- 4 B of  FIG. 4A . 
         FIG. 4C  is a cross-sectional view cut along line  4 C- 4 C of  FIG. 4A . 
         FIG. 4D  is a cross-sectional view cut along line  4 D- 4 D of  FIG. 4A . 
         FIG. 5A  is a cross-sectional view cut along line  4 C- 4 C, in which a first sealing member is provided in the state shown in  FIG. 4A . 
         FIG. 5B  is a cross-sectional view cut along line  4 D- 4 D, in which a first sealing member is provided in the state shown in  FIG. 4A . 
         FIG. 6A  is a cross-sectional view cut along line  4 C- 4 C, in which a second sealing member is provided in the state shown in  FIG. 5A , according to a second embodiment. 
         FIG. 6B  is a cross-sectional view cut along line  4 D- 4 D, in which a second sealing member is provided in the state shown in  FIG. 5A , according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a detailed description is given on the embodiments of the present invention with reference to the accompanying drawings. 
     First Embodiment  
     [Configuration] 
     A first embodiment will be described with reference to  FIGS. 1 ,  2 ,  3 ,  4 A,  4 B,  4 C,  4 D,  5 A, and  5 B. For the sake of clarity of illustration, some members are omitted in some of the drawings; for example, a bonding material  103  and a conducting section  170  are omitted in  FIG. 2 , and a first sealing member  171  is omitted in  FIG. 4A . 
     [Configuration of Distal End Section  10   a  of Endoscope] 
     As shown in  FIG. 1 , an endoscope, not shown, includes a hollow, elongated insertion section  10 , which is inserted into a lumen such as in a body cavity. The distal end section  10   a  of the insertion section  10  includes a light guide  20 , which illuminates an observation target with illumination light by guiding the illumination light thereto, and an image pickup unit  30  configured to capture an image of the observation target. The distal end section  10   a  further includes a lens frame  40  holding the image pickup unit  30 , and a drive element  50  provided in the lens frame  40  and configured to focus and zoom by driving the lens  33  of the image pickup unit  30 . 
     Since the light guide  20  is connected with a light source device, not shown, via the insertion section  10  and an operating section, not shown, of the endoscope, light is supplied to the light guide  20 . The light guide  20  emits illumination light toward the outside from a distal end section of the light guide  20 . 
     The image pickup unit  30  includes a lens cover  31  provided inside the distal end section  10   a  so as to be exposed from a distal end surface of the distal end section  10   a  toward the outside, and a lens  33  provided at the back of the lens cover  31 . The image pickup unit  30  further comprises an image pickup device  35  provided at the back of the lens  33 , and an image pickup cable  37 , which is connected with the image pickup device  35 , and via which electricity is supplied to the image pickup device  35 , a control signal for controlling the image pickup device  35  is sent to the image pickup device  35 , and a video signal captured by the image pickup device  35  is transmitted. 
     The image pickup cable  37  is inserted up through a connection connector via the insertion section  10 , the operating section, and a universal cord. Since the connection connector is connected with a control device, not shown, for controlling the endoscope, the image pickup cable  37  is connected with the control device. Thereby, the electricity that drives the image pickup device  35  and the control signal are supplied to the image pickup cable  37 . Thus the image pickup cable  37  supplies and sends the electricity and the control signal to the image pickup device  35 . Since the connection connector is connected with the control device, a video signal captured by the image pickup device  35  is transmitted to the control device. 
     The lens cover  31  does not need to be a cover member in a simple plate shape, but may be formed in the shape of a lens. In the description that follows, at least one of the lens cover  31  and the lens  33  of the distal end section  10   a , which prevent fogging when the insertion section  10  is inserted into a body cavity or the like, will be referred to as an optical member. The optical member only needs to be provided inside the distal end section  10   a , so as to be exposed toward the outside from the distal end surface of the distal end section  10   a , for example. 
     The drive element  50  includes a motor, for example. The drive element  50  is connected to a drive cable  51 , via which electricity is supplied to the drive element  50  and a drive signal for controlling the drive element  50  is sent to the drive element  50 . 
     The drive cable  51  is inserted up through the connection connector via the insertion section  10 , the operating section, and the universal cord. Since the connection connector is connected with the control device, not shown, the drive cable  51  is connected with the control device. Thereby, the electricity and the control signal that drive the drive element  50  are supplied to the drive cable  51 . The drive cable  51  supplies the electricity and the control signal to the drive element  50 . 
     The lens frame  40  is formed of a cylindrical member, for example. The lens frame  40  houses the image pickup unit  30  in the cylinder. 
     As shown in  FIG. 1 , the distal end section  10   a  further includes an inner frame  60  holding the light guide  20  and the lens frame  40 , and an outer frame  70  covering the inner frame  60  and functioning as the outermost layer of the distal end section  10   a.    
     The inner frame  60  is formed of metal, for example, and the outer frame  70  is formed of a resin, for example. 
     [Fogging of Optical Member] 
     The endoscope including the distal end section  10   a  is usually provided in an environment in which the temperature and humidity are managed, such as a treatment room. Accordingly, the distal end section  10   a  is subjected to such a temperature and humidity before use. When the insertion section  10  is inserted into a body cavity, a difference in temperature between the room and the body or a highly humid environment (humidity of approximately 98%-100%) of the interior of the body cavity, for example, causes fogging in the optical member such as the lens cover  31 , which significantly reduces the imaging field of vision. 
     [Configuration  1  of Endoscope Fogging Prevention System  100  (Prevention Unit  100 )] 
     In view of the above, in the endoscope and the control device, not shown, for controlling the endoscope, an endoscope fogging prevention system  100  configured to prevent fogging of the endoscope is provided, as shown in  FIGS. 1 ,  2 , and  3 . The fogging prevention system  100  includes an endoscope fogging prevention unit (hereinafter referred to as a prevention unit  110 ) provided inside the distal end section  10   a  of the insertion section  10  and configured to prevent fogging that occurs in the optical member provided inside the distal end section  10   a.    
     The prevention unit  110  includes a heating section  120  provided in the lens frame  40 , for example, and including a heater configured to heat the interior of the distal end section  10   a  including the lens cover  31  via the lens frame  40  so as to prevent fogging that occurs in the optical member such as the lens cover  31 , and a measuring section  130  provided in the lens frame  40 , for example, and including a temperature sensor configured to measure the temperature of the interior of the distal end section  10   a  including the lens cover  31  via the lens frame  40 . The prevention unit  110  further includes a wiring substrate section  140 , which is a flexible substrate on which the heating section  120  and the measuring section  130  are mounted by means of a surface mounting technique, for example. 
     As shown in  FIG. 2 , the back surface of the prevention unit  110 , for example, is bonded to an outer periphery of the lens frame  40 , for example, via an adhesive agent  101  having, for example, a high thermal conductivity. Alternatively, a very thin layer of an adhesive agent having a low conductivity may be applied as the adhesive agent  101 . As shown in  FIG. 1 , the heating section  120  and the measuring section  130  only need to be provided inside the distal end section  10   a . Accordingly, the heating section  120  and the measuring section  130  may be provided in an inner frame  60  holding the lens unit, for example. The lens unit includes the lens cover  31 , the lens  33 , and the lens frame  40  holding the lens cover  31  and the lens  33 , for example. 
     As shown in  FIGS. 1 and 2 , the heating section  120  is provided so as to be adjacent to the measuring section  130  in a longitudinal direction of the distal end section  10   a , for example. The heating section  120  is provided at a desired interval from the measuring section  130 , for example. The heating section  120  is arranged at a distance farther from the lens cover  31  (surface of the distal end section  10   a ) than the measuring section  130 , for example. It is to be noted that the placement of the heating section  120  and the measuring section  130  may be reversed. Further, the positional relationship between the heating section  120  and the measuring section  130  is not particularly limited. Moreover, the heating section  120  and the measuring section  130  may be mounted on different flexible substrates. 
     [Heating Section  120 ] 
     The heating section  120  heats the interior of the distal end section  10   a  such that the temperature of the lens cover  31  becomes higher than the temperature of the body but not so high as to damage the body tissue, for example. The temperature is set in a range between approximately 38° C. and 42° C., for example. The heating section  120  heats the interior of the distal end section  10   a  such that the temperature of the optical member is set within the above-described range. The heating section  120  may either directly heat the optical member, or indirectly heat the optical member via the lens frame  40  or the inner frame  60 , for example. 
     As shown in  FIG. 2 , the heating section  120  includes a heating chip  121 , for example. The heating chip  121  includes a ceramic substrate  123 , a metal resistance  125  provided on the substrate  123 , and a pad  127  provided on the substrate  123  and electrically connected to the metal resistance  125 . The metal resistance  125  is formed in the shape of a thin film or paste, and functions as a heating element. The pad  127  is formed as a current introduction terminal. The heating pad  121  may be formed as a resistive element formed of a bulk obtained by molding a resistive material in the shape of chips by sintering, for example. In the description that follows, the term “bulk” refers to chip-shaped molding obtained by sintering a material, for example. 
     [Measuring section  130 ] 
     The measuring section  130  measures the temperature of the interior of the distal end section  10   a , for example. 
     As shown in  FIG. 2 , the measuring section  130  includes a temperature sensor chip  131 , for example. The temperature sensor chip  131  includes a thermistor body  133  formed of a bulk, and a pad  137  provided on the thermistor body  133  and electrically connected to the thermistor body  133 . The thermistor body  133  functions as a temperature-sensing element. The pad  137  is formed as a current introduction terminal. It is also possible to make a ceramic substrate a base of the temperature sensor chip  131 , as in the heating chip  121 , and form a thermistor resistance or a metal resistance in the shape of a thin film or paste on the ceramic substrate. 
     [Wiring Substrate Section  140 ] 
     As shown in  FIGS. 4A ,  4 B,  4 C, and  4 D, the heating section  120  and the measuring section  130  are mounted on the wiring substrate section  140 . Accordingly, the wiring substrate section  140  includes a base layer  141 , a wiring portion  143  provided on the base layer  141  and connected to the heating section  120  and the measuring section  130 , and a cover member  145  covering the wiring portion  143  and having insulating properties. 
     As shown in  FIG. 4A , the wiring substrate section  140  includes a wiring area portion  140   a , which functions as an area portion in which the wiring portion  143  connected to the heating section  120  and the measuring section  130  is mainly mounted, and a mounting area portion  140   b , which functions as an area portion in which the heating section  120  and the measuring section  130  are mainly mounted. 
     The base layer  141  includes an insulating film formed of polyimide, for example. 
     The wiring portion  143  includes a heating-side wiring portion  143   a  connected to the heating section  120 , and a measuring-side wiring portion  143   b  connected to the measuring section  130 . The heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b  are provided on the base layer  141 . The heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b  are of different systems. The heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b  are formed of copper foil. 
     As shown in  FIGS. 4A and 4C , one end portion of the heating-side wiring portion  143   a  is bonded to the pad  127  (not shown in  FIGS. 4A and 4C ) of the heating section  120  via a bonding material  103 , which may be solder, for example. Thereby, the heating section  120  is electrically connected to the heating-side wiring portion  143   a . The one end portion including the bonding material  103  and the pad  127  function as an electrical connection part between the heating section  120  and the heating-side wiring portion  143   a.    
     Further, as shown in  FIGS. 4A and 4D , one end portion of the measuring-side wiring portion  143   b  is bonded to the pad  137  (not shown in  FIGS. 4A and 4C ) of the measuring section  130  via a bonding material  103 , which may be solder, for example. Thereby, the measuring section  130  is electrically connected to the measuring-side wiring portion  143   b . The one end portion including the bonding material  103  and the pad  137  function as an electrical connection part between the measuring section  130  and the measuring-side wiring portion  143   b.    
     The other end portion of the heating-side wiring portion  143   a  and the other end portion of the measuring-side wiring portion  143   b  function as a lead portion exposed from a cover member  145 , as shown in  FIG. 4A . The other end portions of the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b  are connected to a lead line, not shown. The lead line is inserted up through the connection connector via the insertion section  10 , the operating section, and the universal cord. Since the connection connector is connected with the control device, the wiring portion  143  is connected with the control device. Thereby, the electricity and the control signal that drive the heating section  120  are supplied to the heating section  120  via the lead line and the heating-side wiring portion  143   a . Further, the electricity and the control signal that drive the measuring section  130  are supplied to the measuring section  130  via the lead line and the measuring-side wiring portion  143   b . Since the connection connector is connected with the control device, temperature data contained in detection data detected by the measuring section  130  is transmitted to the control device via the measuring-side wiring portion  143   b  and the lead line. 
     As shown in  FIGS. 4A and 4B , the cover member  145  includes an insulating film formed of polyimide, for example. The cover member  145  covers the entire wiring portion  143  including the base layer  141  in the wiring area portion  140   a . The cover member  145  covers the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b  excluding the electrical connection part between the heating section  120  and the measuring section  130  in the mounting area portion  140   b , as shown in  FIGS. 4A ,  4 C, and  4 D. 
     [Configuration  2  of Fogging Prevention System  100  of Endoscope (Control Unit  150 )] 
     The fogging prevention system  100  further includes a control unit  150  configured to control driving of the heating section  120  on the basis of temperature information of the interior of the distal end section  10   a  measured by the measuring section  130 , as shown in  FIG. 3 . The control unit  150  may, for example, be formed separately from the endoscope. The control unit  150  is provided in the control device, not shown, connected to the universal cord of the endoscope, for example, and configured to control the endoscope. 
     As shown in  FIG. 3 , the control unit  150  includes a temperature acquisition section  151  configured to acquire the actual temperature of the interior of the distal end section  10   a  measured by the measuring section  130 , and a power output section  153  configured to output to the heating section  120  an amount of electricity (hereinafter referred to as heater driving power) necessary for driving the heating section  120 . 
     As also shown in  FIG. 3 , the control unit  150  further includes a control section  155  configured to control the power output section  153 , such that the control section  155  calculates a difference between a temperature acquired by the temperature acquisition section  151  and a target temperature set in advance, and calculates an amount of heater driving power that eliminates the difference on the basis of the calculated difference, and the power output section  153  outputs the calculated amount of heater driving power to the heating section  120 . The target temperature includes a temperature that prevents fogging of an optical member such as the lens cover  31  by heating the optical member, for example. Further, the target temperature includes a temperature in the outer frame  70 , which is the outermost part of the distal end section  10   a , and in particular, is a temperature in the vicinity of the heating section  120  that is at or below a temperature that is not too high to damage body tissue. The target temperature can, for example, be appropriately adjusted as desired by the control unit  150 , for example. The target temperature is recorded in advance in a recording section, not shown, provided in the control unit  150 , for example. 
     The temperature acquisition section  151  acquires a temperature at a desired timing or during a desired period of time, for example. 
     A feedback on the temperature measured by the measuring section  130  is given to the control unit  150 . By repeatedly giving feedback, the temperature of the interior of the distal end section  10   a  is controlled with high precision such that the heating temperature of the heating section  120  is set to the target temperature. Examples of approaches for controlling the heating section  120  include ON-OFF control, PWM control, and PID control. 
     [Insulating Properties of Prevention Unit  110 ] 
     In the above-described feedback, the insulating properties between the prevention unit  110  and the interior of the distal end section  10   a  play an important factor in controlling the temperature of the interior of the distal end section  10   a  with high precision. 
     When a surgical endoscope is used together with a treatment tool, not shown, for treating an affected part by an electric action, for example, there is the possibility that the prevention unit  110  may be effected by static electricity, for example, from the outside of the prevention unit  110 , such as the treatment tool. Static electricity may cause a deterioration in performance of the prevention unit  110 , such as the temperature control performance. It is therefore necessary for the prevention unit  110  to have increased resistance to static electricity and have insulating properties. 
     [Conducting Section  170  and Conductor-side Wiring Portion  143   c]   
     As shown in  FIGS. 4A ,  4 C,  4 D,  5 A, and  5 B, in consideration of the above-described insulating properties, the prevention unit  110  further includes a conducting section  170  provided on the base layer  141  so as to surround the heating section  120  and the measuring section  130  in the plane direction of the base layer  141  and be exposed to the cover member  145 . 
     As shown in  FIG. 4A , the conducting section  170  is provided only in the mounting area portion  140   b . The conducting section  170  is formed approximately in the shape of a frame in a figure of the numeral eight (8), for example. The conducting section  170  is provided in the periphery of the heating section  120  and in the periphery of the measuring section  130 . Further, the conducting section  170  is provided in the periphery of the heating section  120  and the periphery of the measuring section  130  in the plane direction of the mounting area portion  140   b , so as to surround the heating section  120  and the measuring section  130 . The conducting section  170  surrounding the heating section  120  is integrally formed with the conducting section  170  surrounding the measuring section  130 . The conducting section  170  is provided in proximity to the heating section  120  and the measuring section  130 . 
     Further, as shown in  FIG. 4A , the wiring portion  143  further includes a conductor-side wiring portion  143   c  electrically connected to the conducting section  170 . The conductor-side wiring portion  143   c  is of a system different from that of the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b . The conductor-side wiring portion  143   c  and the conducting section  170  are formed of a series of copper foil. As shown in  FIG. 4B , the conductor-side wiring portion  143   c  is covered by one cover member  145 , together with the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b . The conductor-side wiring portion  143   c  should preferably have a width greater than that of the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b.    
     As shown in  FIG. 4A , one end portion of the conductor-side wiring portion  143   c  is placed in an interface region between the wiring area portion  140   a  and the mounting area portion  140   b , and is integrally formed with the conducting section  170  in the interface region. The other end portion of the conductor-side wiring portion  143   c  is connected to a ground (GND) provided in the control device, not shown, via a lead line, not shown. The GND is of a system different from that of the heating-side wiring portion  143   a  and the measuring-side wiring portion  143   b.    
     Thereby, the conducting section  170  is connected to the GND via the conductor-side wiring portion  143   c  and the lead line. 
     In the present embodiment, it is necessary to prevent a signal from accidentally flowing to the conducting section  170 , the conductor-side wiring portion  143   c , and the lead line. It is therefore necessary for the conducting section  170  to have desired insulating resistance to the outside. In other words, the conducting section  170  has the lowest insulating properties against the outside in the mounting area portion  140   b . In view of the above, Configurations 1-3, as will be listed below, can be taken as exemplary configurations. 
     Configuration 1: The conducting section  170  includes a non-conducting section provided in an outer periphery of the conducting section  170 . 
     Configuration 2: A space is provided between the conducting section  170  and the endoscope structure. 
     Configuration 3: Resistance elements such as a resistive element, a capacitor element, a varistor element, and a diode element are provided between the conducting section  170  and the GND. 
     [First Sealing Member  171 ] 
     As shown in  FIGS. 5A and 5B , in consideration of the insulating properties, the prevention unit  110  further includes a first sealing member  171  provided at least in the connection part between the wiring portion  143  and the heating section  120  and the measuring section  130  such that the conducting section  170  is exposed, configured to seal the connection part, and having insulating properties. The first sealing member  171  is omitted in drawings other than  FIGS. 5A and 5B  in the present embodiment, for the sake of clarity of illustration. The first sealing member  171  insulates electricity and a control signal to be supplied to the heating section  120  and the measuring section  130  from the outside. 
     The first sealing member  171  is provided only in the mounting area portion  140   b . The first sealing member  171  is formed in the shape of a frame. Further, the first sealing member  171  is provided in the periphery of the heating section  120  so as to surround the heating section  120  in the plane direction of the base layer  141 , in an approximately same manner as in the conducting section  170 . Further, the first sealing member  171  is provided in the periphery of the measuring section  130  so as to surround the measuring section  130  in an approximately same manner as in the conducting section  170 . 
     As shown in  FIG. 5A , the connection part between the wiring portion  143  (heating-side wiring portion  143   a ) and the heating section  120  includes a surface of the base layer  141 , the periphery of the heating-side wiring portion  143   a , the periphery of the bonding material  103 , and the periphery of the heating section  120 , for example. The connection part includes an electrical connection part between the heating section  120  and the heating-side wiring portion  143   a . The first sealing member  171  is provided between the conducting section  170  and the heating-side wiring portion  143   a  in the plane direction of the base layer  141 . 
     When, for example the heating section  120  includes the heating chip  121 , the substrate  123 , the metal resistance  125 , and the pad  127 , the ceramic substrate  123  has insulating properties. Accordingly, in consideration of heat conducting properties, the first sealing member  171  seals the connection part between the wiring portion  143  and the heating section  120  such that a bonding surface  120   b  of the heating section  120  bonded to the lens frame  40  is exposed, as shown in  FIG. 5A . 
     As shown in  FIG. 5B , the connection part between the wiring portion  143  (measuring-side wiring portion  143   b ) and the measuring section  130  includes a surface of the base layer  141 , the periphery of the measuring-side wiring portion  143   b , the periphery of the bonding material  103 , and the periphery of the measuring section  130 , for example. The connection part includes an electric connection part between the measuring section  130  and the measuring-side wiring portion  143   b . The first sealing member  171  is provided between the conducting section  170  and the measuring-side wiring portion  143   b  in the plane direction of the base layer  141 . 
     When the measuring section  130  is formed of a bulk, for example, the first sealing member  171  seals the entire heating section  120  including the connection part, such that the conducting section  170  is exposed and the measuring section  130  is embedded in the first sealing member, as shown in  FIG. 5B . 
     As a result thereof, the conducting section  170  has the lowest insulating properties against the outside in the mounting area portion  140   b.    
     [Operation Method] 
     An operation method of the present embodiment will now be discussed. 
     Static electricity applied from the outside enters into the base layer  141 , the wiring portion  143 , the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , the heating section  120 , and the measuring section  130 . As a result thereof, the heating section  120  and the measuring section  130  may be denaturized, or may be damaged. In such a case, there is the possibility that the prevention unit  110  cannot maintain desired performance. 
     In the present embodiment, on the other hand, the base layer  141  has insulating properties, and the wiring portion  143  is covered with the cover member  145  having insulating properties. This prevents entry of static electricity into the base layer  141  and the wiring portion  143 . 
     Further, by setting the base layer  141  and the cover member  145  to have a desired thickness and setting a margin from the wiring portion  143  to an end portion of the wiring substrate section  140  as desired, entry of static electricity into the base layer  141  and the wiring portion  143  is prevented. 
     In the present embodiment, the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , the heating section  120 , and the measuring section  130  are sealed by the first sealing member  171  having insulating properties. This prevents entry of static electricity into the sealed area. 
     There is the possibility, however, that static electricity enters from an area having low insulating properties. The area having low insulating properties includes, for example, an interface between the heating section  120  and the first sealing member  171 , an interface between the measuring section  130  and the first sealing member  171 , an interface between the base layer  141  and the first sealing member  171 , and a part of the first sealing member  171  having a small thickness. That is, the area having low insulating properties corresponds to the mounting area portion  140   b.    
     A common approach to prevent the above-described entry of static electricity is to increase a creepage distance in which static electricity enters, i.e., to cause the first sealing member  171  to firmly perform the sealing. In this approach, however, the size of the prevention unit  110  inevitably increases, which affects heat conducting properties between the prevention unit  110  and the interior of the distal end section  10   a.    
     In view of the above, in the present embodiment, the conducting section  170 , which functions as an area having the lowest insulating properties, is provided in the mounting area portion  140   b . Thereby, in the mounting area portion  140   b , static electricity preferably flow to the conducting section  170  instead of over the base layer  141 , the wiring portion  143 , the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , and parts of the heating section  120  and the measuring section  130  having low insulating properties. Thus, the static electricity flows to the GND from the conducting section  170  via the conductor-side wiring portion  143   c  and the lead line. 
     Thereby, the base layer  141 , the wiring portion  143 , the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , the heating section  120 , and the measuring section  130  are protected from static electricity. 
     Further, the conducting section  170  surrounds the heating section  120  and the measuring section  130  in the plane direction of the base layer  141 , is in proximity to the heating section  120  and the measuring section  130 , and is exposed to the cover member  145 . 
     Accordingly, static electricity preferably and reliably flows to the conducting section  170 . Thereby, the base layer  141 , the wiring portion  143 , the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , the heating section  120 , and the measuring section  130  are reliably protected from static electricity by the conducting section  170 . 
     Further, the conducting section  170  is provided on the base layer  141 . Accordingly, relative positions between the conducting section  170  and the heating section  120  and the measuring section  130  are determined with high precision. 
     Thereby, an improved protection effect against static electricity is achieved, compared to the state in which a protection mechanism against static electricity is provided separately from a heating unit as an exterior component, for example. 
     Thus, by providing the conducting section  170 , a high resistance to static electricity is reliably secured. 
     [Effect] 
     As described above, in the present embodiment, static electricity preferably flows to the conducting section  170  in the mounting area portion  140   b.    
     In the present embodiment, in particular, the conducting section  170  surrounds the heating section  120  and the measuring section  130  in the plane direction of the base layer  141 , is in proximity to the heating section  120  and the measuring section  130 , and is exposed to the cover member  145 , as shown in  FIG. 4A . Thereby, static electricity preferably and reliably flows to the conducting section  170  in the mounting area portion  140   b.    
     Further, in the present embodiment, as shown in  FIGS. 4C ,  4 D,  5 A, and  5 B, the conducting section  170  is provided on the base layer  141 , and relative positions of the conducting section  170 , the heating section  120 , and the measuring section  130  are determined with high precision. Accordingly, an increased protection effect against static electricity is achieved. 
     It is thus possible to reliably secure a high resistance to static electricity in the present embodiment. 
     Further, in the present embodiment, since the conducting section  170  is provided, it is not necessary to increase the creepage distance in which static electricity enters, and to cause the first sealing member  171  to firmly perform the sealing. It is thus possible in the present embodiment to reduce the size of the prevention unit  110 , and to prevent heat conducting properties between the prevention unit  110  and the interior of the distal end section  10   a  from being affected. 
     Further, in the present embodiment, since the first sealing member  171  is provided as shown in  FIGS. 5A and 5B , it is possible to prevent entry of static electricity into the connection part between the heating-side wiring portion  143   a  and the heating section  120 , the connection part between the measuring-side wiring portion  143   b  and the measuring section  130 , the heating section  120 , and the measuring section  130 . It is thereby possible to reliably secure high resistance to static electricity in the present embodiment by providing the conducting section  170  and the first sealing member  171 . 
     The conducting section  170  may include projections such as stud bumps in the mounting area portion  140   b . The projections are formed in the form of dots, for example, and are provided in the vicinity of four corners of the heating section  120  and in the vicinity of four corners of the measuring section  130 , for example. It is thus possible in the present embodiment to reliably let static electricity flow to the conducting section  170  via the projections. 
     Second Embodiment  
     [Configuration] 
     The present embodiment will be described with reference to  FIGS. 6A and 6B . Only structures different from those of the first embodiment will be discussed below. 
     [Second Sealing Member  173 ] 
     A prevention unit  110  further includes a second sealing member  173  configured to seal a base layer  141 , a conducting section  170 , and a first sealing member  171  and having a volume resistivity lower than that of the first sealing member  171 , as shown in  FIGS. 6A and 6B . 
     For example, when the heating section  120  includes a heating chip  121 , a ceramic substrate  123 , a metal resistance  125 , and a pad  127 , the ceramic substrate  123  has insulating properties. Accordingly, in consideration of heat conducting properties, the second sealing member  173  seals the base layer  141 , the conducting section  170 , the first sealing member  171 , and the heating section  120 , such that a bonding surface  120   b  of the heating section  120  bonded to a lens frame  40  is exposed, as shown in  FIG. 6A . 
     When a measuring section  130  is formed of a bulk, for example, the second sealing member  173  seals the base layer  141 , the conducting section  170 , and the first sealing member  171 , such that an upper surface of the first sealing member  171  is exposed, as shown in  FIG. 6B . 
     In view of the volume resistances, the first sealing member  171  is formed of an epoxy-based resin, for example, and the second sealing member  173  is formed of an epoxy-based resin into which carbon is added, for example. 
     [Action] 
     The volume resistance of the second sealing member  173  is lower than the volume resistance of the first sealing member  171 . Accordingly, in the present embodiment, static electricity preferably flows to the second sealing member  173  instead of over the first sealing member  171 . After that, the static electricity flows from the second sealing member  173  to the conducting section  170 . 
     [Effect] 
     In the present embodiment, the second sealing member  173  is provided. Thereby, in the present embodiment, the conducting section  170  reliably obtains desired insulating resistance to the outside. 
     Further, in the present embodiment, the volume resistance of the second sealing member  173  is lower than the volume resistance of the first sealing member  171 . Thereby, in the present embodiment, priorities in insulating properties can be assigned to the area to be protected from static electricity, such as a connection part between the wiring portion  143  and the heating section  120  and the measuring section  130 , the heating section  120  and the measuring section  130 , and the area through which static electricity flows, such as the conducting section  170 , by the first sealing member  171  and the second sealing member  173 . It is thereby possible in the present embodiment to reliably and stably secure high resistance to static electricity, and to provide the conducting section  170  reliably having desired insulating resistance against the outside. 
     Further, in the present embodiment, since the second sealing member  173  is provided, the conducting section  170  reliably achieves desired insulating resistance, compared to a configuration in which a space is provided between the conducting section  170  and an endoscope structure. Further, in the present embodiment, since the second sealing member  173  is provided, it is possible to reliably make the potential of the conducting section  170  close to the potential of the GND, compared to a configuration in which a resistive element is provided between a conducting section  170  and a GND. 
     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.