Patent Publication Number: US-6656112-B2

Title: Distal endoscope part having light emitting source such as light emitting diodes as illuminating means

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a divisional of U.S. patent application Ser. No. 09/391,279, filed Sep. 7, 1999, now U.S. Pat. No. 6,488,619 in the name of Hirofumi MIYANAGA and entitled “DISTAL ENDOSCOPE PART HAVING LIGHT EMITTING SOURCE SUCH AS LIGHT EMITTING DIODES AS ILLUMINATING MEANS”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a distal endoscope part, or more particularly, a distal endoscope part characterized by a portion thereof in which light emitting diodes serving as an illuminating means are placed. 
     2. Description of the Related Art 
     Structures having a light emitting source such as light emitting diodes incorporated as an illuminating means in a distal endoscope part have been proposed in the past. 
     For example, Japanese Unexamined Patent Publication No. 63-260526 describes a distal endoscope part for side viewing in which a plurality of light emitting diodes is placed circumferentially with an objective optical system as a center in order to improve the light emitting characteristic of the distal part. 
     However, according to the related art (Japanese Unexamined Patent Publication No. 63-260526), the light emitting diodes are placed on a spherical surface on the outer circumference of an endoscope. The plurality of light emitting diodes must be attached one by one to a distal member. 
     When the light emitting diodes must be attached one by one to the distal endoscope member, there is difficulty in narrowing the spacing between adjoining light emitting diodes. A side viewing endoscope having a plurality of light emitting diodes placed on the outer circumference of an objective optical system has a drawback that the distal part thereof is large in size. 
     Moreover, Japanese Unexamined Patent Publication No. 8-117184 has proposed a structure having a light emitting source as an illuminating means incorporated in a distal endoscope part. Japanese Utility Model Registration No. 3007137 has proposed a structure having light emitting diodes as an illuminating means placed around a camera in a distal part of a tubular examination camera system. In these structures, the light emitting unit is protected with a cover glass or acrylic plate placed on the front surface thereof. 
     Especially in the Japanese Utility Model Registration No. 3007137, the cover glass over the front surfaces of the light emitting diodes also works to leave the light emitting diodes watertight. 
     However, when a watertight structure is realized using a transparent member such as the cover glass as it is as described in the related art, the cover glass must have a thickness large enough to position the perimeter thereof relative to a metallic member and support it. In the structure having the cover glass, therefore, mechanical members must be made larger by a dimension corresponding to the perimeter used for positioning. 
     As described in the Japanese Utility Model Registration No. 3007137, a structure has the light emitting diodes, which serves as an illuminating means, placed on the outer circumference of an imaging unit and a transparent member placed on the front surfaces of the light emitting diodes. This poses a problem in that the outer diameter of the distal part must be made larger by a dimension corresponding to the perimeter of the transparent member. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a distal endoscope part making it possible to realize a side viewing endoscope having a plurality of light emitting diodes placed on the outer circumference of an objective optical system without an increase in the outer diameter of the distal part. 
     Another object of the present invention is to provide a distal endoscope part making it possible to realize a watertight structure without the necessities of placing a transparent member over the front surfaces of light emitting diodes and of increasing the outer diameter of the distal part. 
     A distal endoscope part in accordance with the present invention has a plurality of light emitting diodes for supplying illumination light placed as an illuminating means on the outer circumference of an objective optical system. The plurality of light emitting diodes is mounted on a substrate and united therewith. A sub-assembly of the plurality of united light emitting diodes is placed on a plane containing the longitudinal axis of an insertion unit of an endoscope and its neighborhood. Consequently, although the side viewing endoscope has the plurality of light emitting diodes placed on the outer circumference of the objective optical system, the outer diameter of the distal part thereof is not large in size. 
     Other features of the present invention and advantages thereof will be fully apparent from the description below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 to FIG. 10 relate to the first embodiment of the present invention; 
     FIG. 1 shows the configuration of a side viewing endoscope; 
     FIG. 2 is a longitudinal sectional view showing the structure of a distal endoscope part shown in FIG. 1; 
     FIG. 3 is a cross sectional view of the A—A plane of the distal endoscope part shown in FIG. 2; 
     FIG. 4 is a top view of the distal endoscope part shown in FIG. 2; 
     FIG. 5 is a longitudinal sectional view showing the BB plane of the distal endoscope part shown in FIG. 4; 
     FIG. 6 is a cross sectional view showing the C—C plane of the distal endoscope part shown in FIG. 2; 
     FIG. 7 is a first explanatory diagram for explaining a first variant of the distal endoscope part shown in FIG. 1; 
     FIG. 8 is a second explanatory diagram for explaining the first variant of the distal endoscope part shown in FIG. 1; 
     FIG. 9 is a first explanatory diagram for explaining a second variant of the distal endoscope part shown in FIG. 1; 
     FIG. 10 is a second explanatory diagram for explaining a second variant of the distal endoscope part shown in FIG. 1; 
     FIG. 11 to FIG. 21 relate to the second embodiment of the present invention; 
     FIG. 11 shows the configuration of a side viewing endoscope; 
     FIG. 12 is a longitudinal sectional view showing the structure of the distal endoscope part shown in FIG. 11; 
     FIG. 13 is a cross sectional view showing the A—A plane of the distal endoscope part shown in FIG. 12; 
     FIG. 14 is a top view of the distal endoscope part shown in FIG. 12; 
     FIG. 15 is a longitudinal sectional view showing the B—B plane of the distal endoscope part shown in FIG. 12; 
     FIG. 16 is a cross sectional view showing the C—C plane of the distal endoscope part shown in FIG. 12; 
     FIG. 17 is a cross sectional view showing the D—D plane of the distal endoscope part shown in FIG. 12; 
     FIG. 18 is a cross sectional view showing the E—E plane of the distal endoscope part shown in FIG. 12; 
     FIG. 19 is a longitudinal sectional view showing the structure of a control unit included in the distal endoscope part shown in FIG. 11; 
     FIG. 20 shows the structure of a variant of the control unit shown in FIG. 19; 
     FIG. 21 shows the structure of a light emitting diode included in the distal endoscope part shown in FIG. 14; 
     FIG. 22 to FIG. 24 relate to the third embodiment of the present invention; 
     FIG. 22 is a longitudinal sectional view showing the structure of a distal endoscope part; 
     FIG. 23 is a cross sectional view showing the F—F plane of the distal endoscope part shown in FIG. 22; and 
     FIG. 24 is a cross sectional view showing the G—G plane of the distal endoscope part shown in FIG.  22 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     As shown in FIG. 1, a side viewing endoscope  1  has an insertion unit  2  to be inserted into an intracorporeal cavity. A distal endoscope part (hereinafter referred to as a distal part) in accordance with the present invention attached to the distal end of the insertion unit  2  includes an imaging means and light emitting diodes serving as an illuminating means. A control unit attached to the proximal end of the insertion unit  2  has a light level adjustment knob  5  used to adjust an amount of light emitted from the light emitting diodes in the distal part  3 . 
     An optical image of an object illuminated the light emitting diodes is projected on an imaging unit included in the distal part  3 , and converted into an electric signal. The electric signal is sent to a camera control unit  7  over a camera control cable  6 . Image data represented by the electric signal is processed by the camera control unit  7  that is powered by an AC adapter  8 . An image signal produced by the camera control unit  7  is transferred to a monitor  10  over a monitor cable  9 . An endoscopic image is then displayed. 
     As shown in FIG.  2  and FIG. 3, an imaging unit  13  for converting an optical signal into an electric signal is fixed to a body  15  with a holder  14  between them by means of screws  16 . The imaging unit  13  consists of a solid-state imaging device  11  and electronic parts  12 . 
     An objective sub-assembly  17  for converging an optical image at the solid-state imaging device  11  is placed ahead of the solid-state imaging device  11 . The optical image represents an object located in a direction of side viewing (at a right angle with respect to the longitudinal direction of the insertion unit  2 ). 
     A signal cable  18  over which a signal is transferred from the camera control unit  7  to the imaging unit  13 , and power cables  20  over which power is supplied to the light emitting diodes  19  serving as an illuminating means are passed through the insertion unit  2 . 
     As shown in FIG. 4 to FIG. 6, the light emitting diodes  19  serving as an illuminating means for irradiating illumination light in the direction of side viewing (at a right angle with respect to the longitudinal direction of the insertion unit  2 ) are soldered to a substrate  21 . The power cables  20  are also soldered to the substrate  21 . The substrate  21  having the light emitting diodes and power cables united therewith is fixed to a body  22  by means of screws A  23 . 
     The substrate  21  having the plurality of light emitting diodes  19  united therewith lies on a plane containing the longitudinal axis  25  of the insertion unit and its neighborhood. 
     Likewise, part of a first objective surface  30  lies on the plane containing the longitudinal axis  25  of the insertion unit of the endoscope and its neighborhood. As long as the outer diameter of the endoscope remains unchanged, the plane containing the longitudinal axis  25  of the insertion unit and its neighborhood provides the largest area for the light emitting diodes. If the light emitting diode sub-assembly  19  is placed on the plane, the outer diameter of the distal part  3  can be made as small as possible. 
     The light emitting diodes  19  are fixed to the body  22  together with the substrate  21 . Thereafter, a substantially transparent filler  24  is injected to fully cover the surroundings of the light emitting diodes  19  and the light emitting surfaces thereof. Even the tops of the light emitting diodes  19  are covered with the filler  24 , whereby the light emitting diodes  19  are not only protected to be blocked from outside but also left watertight. 
     The light emitting diodes  19  on the substrate  21  may be, as shown in FIG.  7  and FIG. 8, mounted in pairs. In this case, the sub-assembly of the light emitting diodes mounted on the substrate  21  is attached to a distal mechanical member  32 . Paired light emitting diodes  19  can therefore be located mutually as closely as possible. Consequently, the width  33  of the substrate can be decreased and the outer diameter of the distal part can be minimized. 
     Moreover, as shown in FIG.  9  and FIG. 10, a package for each light emitting diode  19  may be shaped like a sector in order to improve the density of mounted components and the efficiency in emitting light. 
     As mentioned above, according to the present embodiment, the substrate  21  having the plurality of light emitting diodes  19  united therewith is placed on the plane containing the longitudinal axis  25  of the insertion unit and its neighborhood. Part of the first objective surface  30  is also placed on the plane containing the longitudinal axis  25  of the insertion unit and its neighborhood. As long as the outer diameter of the endoscope remains unchanged, the plane containing the longitudinal axis  25  of the insertion unit and its neighborhood can provide the largest area for the light emitting diodes. For this reason, the outer diameter of the distal part  3  can be minimized. 
     In other words, the light emitting diode sub-assembly made by mounting the plurality of light emitting diodes on the substrate is placed on the plane containing the longitudinal axis  25  of the insertion unit and its neighborhood. Therefore, the density of mounted components can be improved and the outer diameter of the distal endoscope part can be minimized. 
     Moreover, the plurality of light emitting diodes can be assembled at a time. This leads to easy assembling. 
     Second Embodiment 
     As shown in FIG. 11, a side viewing endoscope  101  has an insertion unit  102  that is inserted into an intracorporeal cavity. A distal endoscope part  103  (hereinafter referred to as a distal part) in accordance with the present embodiment attached to the distal end of the insertion unit  102  has an imaging means and light emitting diodes serving as an illuminating means. A control unit  104  attached to the proximal end of the insertion unit  102  has a light level adjustment knob  105  used to adjust an amount of light emitted from the light emitting diodes in the distal part  103 . 
     An optical image of an object illuminated by the light emitting diodes is projected on an imaging unit in the distal part  103 , and converted into an electric signal. The electric signal is sent to a camera control unit  107  over a camera control cable  106 . Image data represented by the electric signal is processed by the camera control unit  107  that is powered by an AC adapter  108 . An image signal produced by the camera control unit  107  is transferred to a monitor  110  over a monitor cable  109 . Consequently, an endoscopic image is displayed. 
     As shown in FIG.  12  and FIG. 13, an imaging unit  113  for converting an optical signal to an electric signal is fixed to a body  115  in the distal part  103  with a holder  114  between them by means of screws C  116 . The imaging unit  113  consists of a solid-state imaging device  111  and electronic parts  112 . 
     Moreover, an objective sub-assembly  117  for converging an optical image at the solid-state imaging device  111  is located ahead of the solid-state imaging device  111 . The optical image represents an object located in a direction of side viewing (at a right angle with respect to the longitudinal direction of the insertion unit  2 ). 
     A signal cable  118  over which a signal is transferred from the camera control unit  107  to the imaging unit  113 , and power cables  120  over which power is supplied to the light emitting diodes  119  are passed through the insertion unit  102 . The light emitting diodes  119  serve as an illuminating means and will be described later. 
     As shown in FIG.  14  and FIG. 15, the light emitting diodes  119  serving as an illuminating means for irradiating illumination light in the direction of side viewing (at a right angle with respect to the longitudinal direction of the insertion unit  102 ) are soldered to a substrate  121 . The power cables  120  are also soldered to the substrate  121 . The substrate  121  having the light emitting diodes and power cables united therewith is fixed to a body  122  by means of screws A  123 . 
     The light emitting diodes  119  are fixed to the body  122  together with the substrate  121 . Thereafter, a substantially transparent filler  124  is injected to fully cover the surroundings of the light emitting diodes  119  including the light emitting surfaces thereof. Even the tops of the light emitting diodes  119  are covered with the filler  124 , whereby the light emitting diodes  119  are not only protected to be blocked from outside but also left watertight. 
     As shown in FIG.  16  and FIG. 17, the body  115  and body  122  are secured by a screw B  125 . Part of a lens frame  127  mounted on the outer circumference of an objective  126  located behind a prism and included in the objective sub-assembly  117  is notched. This is because the dimension between the objective  126  and the body  115  that is a mate member is not large enough to tolerate the thickness of the lens frame  127 . 
     Referring back to FIG. 12, a cover A  128  screwed to the body  115  is fixed to the outer circumference of the imaging unit  113 . A cover B  129  is screwed to the cover A  128 . The outer circumference of the imaging unit  113  is thus covered by two covers of the cover A  128  and cover B  129 . This is intended to reinforce the fixation of the imaging unit  113  to the body  115  after the imaging unit is screwed firmly to the body  115 . An adhesive  130  is therefore injected into a space created by the cover A  128 , body  115 , and imaging unit  113 . Since two covers are used in combination, a desired position can be looked at accurately during work. The adhesive  130  can be injected easily. 
     Moreover, as shown in FIG. 18, the signal cable  118  and power cables  120  are sandwiched between the cover B  129  and a fixture  131 . The tensile strengths in the axial direction of the cables are thus improved. The fixture  131  is fixed to the cover B  129  by screws D  132 . 
     FIG. 19 shows the system control unit  103  shown in FIG.  11 . The light level adjustment knob  105  is located on a back end panel  133  of the control unit  104 . The light level adjustment knob  105  is structured not to jut out beyond the outer circumference  134  of the control unit  104 . Even if a worker nonchalantly places the endoscope at a site, the switches including the light level adjustment knob  105  will hardly be flawed. 
     Moreover, the light level adjustment knob  105  may be, as shown in FIG. 20, located on the circumference of the control unit  104 . In this case, the light level adjustment knob  105  will not jut out beyond the outer circumference  134 . 
     FIG. 21 shows the outline of a light emitting diode  119  employed in the second embodiment. The light emitting diode  119  is made by putting a chip (light emitting device)  161  in a center dent of a ceramic package  160  and covering the chip portion with a silicon resin  162 . 
     As mentioned above, in this embodiment, the light emitting diodes  119  are fixed to the body  122  together with the substrate  121 . Thereafter, the substantially transparent filler  124  is injected to fully cover the surroundings of the light emitting diodes  119  including the light emitting surfaces thereof. Since the tops of the light emitting diodes  119  are covered with the filler  124 , it is unnecessary to place a transparent member in front of the light emitting diodes  119  and to increase the outer diameter of the distal part. Moreover, the light emitting diodes  119  can be not only protected to be blocked from outside but also left watertight. 
     The surroundings of the light emitting diodes and the front light emitting surfaces thereof are covered with the filler in order to realize a watertight structure. This makes it unnecessary to ensure a thickness large enough to support a transparent member used to attain a watertight state in the related art. The outer diameter of the distal part can therefore be made smaller. Moreover, the employment of the filler requires a smaller number of members than the employment of the transparent member such as a glass. Besides, the price of the distal part can be lowered. 
     Third Embodiment 
     The third embodiment is substantially identical to the second embodiment. Only a difference will be described. The same reference numerals will be assigned to identical components. 
     As shown in FIG. 22 to FIG. 24, a distal endoscope part  103   a  in accordance with the present embodiment is a distal part for a direct viewing endoscope. An insertion unit including the distal endoscope part  101   a  consists of an optical adapter  140  and an endoscope body  141 . The optical adapter  140  is mounted on the outer circumference of the endoscope body  141  and secured to a setscrew  142 , which can rotate only in a circumferential direction, by means of attaching screws  143 . 
     A plurality of light emitting diodes  119  is placed on the circumference of an objective  144  in the optical adapter  140  with the objective  144  as a center (see FIG.  23 ). The light emitting diodes  119  are mounted on substrates  145  together with contact pins  146 . The substrates  145  are stowed in an adapter body  147  with the light emitting diodes and contact pins united therewith. Thereafter, a substantially transparent filler  148  is injected to fully cover the light emitting diodes  119  including even the tops thereof. The light emitting diodes  119  are thus left watertight. 
     Power is supplied from the endoscope body  141  to the light emitting diodes  119  in the optical adapter  140  over power cables  120 . Specifically, power is delivered to the contact pins  146  in the optical adapter  140  through contact receptacles  149  over the power cables  120 . The power is then supplied to the light emitting diodes  119  via the substrates  145 . A power supply member shall be composed of the contact receptacles  149  and contact pins  146 . The power supply member is isolated from the metallic member of the body  150  by insulators A  151 , insulators B  152 , and insulating tubes  153 , and secured by screws  154  (see FIG.  24 ). 
     Even in this embodiment, the filler  148  is injected to fully cover the light emitting diodes  119  including the tops thereof. The light emitting diodes  119  are thus left watertight. The same advantage as that provided by the second embodiment can therefore be provided. 
     In the present invention, it is apparent that a wide range of different embodiments can be constructed based on the invention without a departure from the spirit and scope of the invention. This invention will be limited by the appended claims but not restricted by any specific embodiments.