JP2010063485A - Illumination optical system for endoscope and endoscope - Google Patents

Abstract

An object of the present invention is to measure the size of an observation object in a non-contact manner without causing an increase in diameter of an insertion portion.
[Solution]
The endoscope is provided with a plurality of illumination windows at the distal end portion of the insertion portion. A plurality of illumination optical systems corresponding to the respective illumination windows are provided in the distal end portion. Each illumination optical system has an irradiation lens 60 including a first lens 66 and a second lens 68. The first lens 66 has a concave surface 66b that is recessed in a hemispherical shape. The second lens 68 has a back surface 68b formed in a curved surface. The first lens 66 diffuses incident light at the concave surface 66b and irradiates it from the illumination window as illumination light. The second lens 68 converts the incident light into a parallel light beam at the back surface 68b and irradiates it from the illumination window as sensing light. As described above, the illumination lens 60 generates the illumination light and the sensing light, so that the diameter of the insertion portion can be prevented from increasing even when the measurement is performed without contact.
[Selection] Figure 5

Description

  The present invention relates to an illumination optical system that generates illumination light for illuminating an observation target, and an endoscope using the illumination optical system.

  In recent years, endoscopes for observing a patient's body cavity have been widely used in medical practice. In endoscopes, there is a demand to be able to measure the size of a specific observation target such as a tumor or an ulcer during observation. In order to meet such a demand, in the endoscope described in Patent Document 1, a length measuring element serving as a length index is projected from the distal end of the insertion portion. In this way, the size of the observation target can be roughly measured by comparing the length measuring element and the observation target on the endoscopic image.

  By the way, when measuring by the above method, if the length measuring element and the observation target are separated from each other, the length measuring element reflected on the near side will naturally appear larger. Therefore, in order to accurately measure the size by the above method, it is necessary to bring the length measuring element into contact with the observation object. However, if the measuring element, which is a rod-shaped protrusion, is brought into contact with the observation target, there is a risk that the inside of the body cavity may be accidentally damaged.

  In order to prevent this, in the endoscope described in Patent Document 2, a plurality of measurement optical fibers are provided separately from the illumination optical fiber, and a parallel light flux is irradiated from each measurement optical fiber. In this endoscope, a light spot is formed on the observation target by the parallel light beam irradiated from each measurement optical fiber. And since the center-to-center distance of each light spot is the same as the center-to-center distance of each measurement optical fiber, by comparing the center-to-center distance of each light spot and the observation object on the endoscopic image, The size of the observation object can be measured without contact.

As described above, the endoscope described in Patent Document 2 can measure the size of the observation object in a non-contact manner, so there is no risk of damaging the body cavity. Further, since a mechanism for projecting and storing the measuring element is not required, the configuration of the endoscope can be simplified.
JP-A-6-304120 JP-A-8-201026

  However, when an optical fiber for measurement is separately provided as in the endoscope described in Patent Document 2, there arises a problem that the diameter of the insertion portion is increased by this amount. In medical endoscopes, in addition to the desire to be able to measure the size of the observation target, there is also a desire to reduce the diameter of the insertion portion as much as possible in order to reduce the burden on the patient. For this reason, in an endoscope, it is desired to be able to measure the size of an observation object in a non-contact manner without increasing the diameter of the insertion portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to allow an endoscope to measure the size of an observation object in a non-contact manner without increasing the diameter of an insertion portion.

  In order to achieve the above object, the present invention generates illumination light for illuminating an observation object from incident light incident with a predetermined divergence angle, and irradiates it from an illumination window provided at the distal end of the insertion portion. In the endoscope illumination optical system, a first curved surface that is formed in a disc shape so that a central portion of the incident light is incident thereon and generates the illumination light by diffusing the incident light, and a diameter of the first curved surface It has a larger diameter and is formed in an annular shape or a disk shape so that the outer peripheral portion of the incident light is incident. By converting the incident light into a substantially parallel light beam, the size of the observation object is measured. It has a 2nd curved surface which produces | generates sensing light, The irradiation lens which irradiates both the said illumination light and the said sensing light from the said illumination window was provided.

  In addition, it is preferable that the said irradiation lens consists of a 1st lens in which the said 1st curved surface was formed, and a 2nd lens in which the said 2nd curved surface was formed.

  A light-shielding member that moves between a position that prevents the outer peripheral portion of the incident light from entering the second curved surface and a position that allows the incidence of the light; It is more preferable to provide sensing light irradiation switching means for switching irradiation / non-irradiation of the sensing light by making light incident on or shielding from the second curved surface.

  It is more preferable to provide a light amount adjusting means for adjusting the light amount of the illumination light irradiated from the irradiation lens.

  Furthermore, the present invention illuminates an observation target from a plurality of illumination windows provided at the distal end of the insertion portion and a plurality of illumination windows corresponding to each of the illumination windows and incident light having a predetermined spread angle. And an illumination optical system that irradiates from the corresponding illumination window, and irradiates a plurality of substantially parallel luminous flux sensing lights from the distal end of the insertion portion, and the observation object is obtained by each sensing light. In the endoscope in which the size of the observation object can be measured in a non-contact manner by comparing the distance between the centers of the plurality of light spots formed on the endoscope and the observation object on the endoscope image. A first curved surface that is formed in a disc shape so that a central portion of the incident light is incident thereon, generates the illumination light by diffusing the incident light, and has a diameter larger than a diameter of the first curved surface; and A second curved surface that is formed in an annular shape or a disk shape so that an outer peripheral portion of the incident light is incident thereon, and generates the sensing light by converting the incident light into a substantially parallel light beam, and the illumination light and the sensing light Each illumination optical system is provided with an irradiation lens that irradiates both from the corresponding illumination window.

  In the present invention, an illumination lens having a first curved surface that generates illumination light and a second curved surface that generates sensing light is provided in the illumination optical system so that both illumination light and sensing light are irradiated from the illumination window. I made it. This eliminates the need to separately provide a light guide or light source for sensing light when irradiating a plurality of sensing lights from the tip of the insertion part and measuring the size of the observation object in a non-contact manner. The size of the observation object can be measured in a non-contact manner without causing an increase in diameter.

  As shown in FIG. 1, an endoscope system 2 includes an electronic endoscope 10 that images a patient's body cavity, a processor device 12 that generates an endoscope image, and a monitor 14 that displays the endoscope image. And a water supply tank 16 for storing water to be sent into the body cavity. The processor device 12 has a function as a light source for supplying light for illuminating the inside of the body cavity and a function as a pump for supplying air for air supply / water supply in addition to the function of generating an endoscopic image. is doing.

  The electronic endoscope 10 includes an insertion unit 20 that is inserted into a body cavity of a patient, an operation unit 22 that is connected to a proximal end portion of the insertion unit 20 and that is operated by a surgeon such as a doctor or a technician, It consists of a universal cord 24 extending from the operation unit 22.

  The electronic endoscope 10 is supplied from the processor device 12 in a normal observation mode in which observation inside the body cavity is performed by irradiating light supplied from the processor device 12 as illumination light from the distal end of the insertion unit 20. A first sensing mode in which the measurement is performed in a non-contact manner by generating sensing light for measuring the size of the observation target from a part of the light and irradiating the sensing light together with the illumination light, and a state of the first sensing mode There are three imaging modes, a second sensing mode that makes the sensing light stand out more by reducing the amount of illumination light.

  In the first sensing mode, observation and measurement can be performed with the same amount of light as in the normal observation mode, but when the distal end of the insertion portion 20 moves away from the observation target, the light diffuses and the sensing light becomes difficult to read. On the other hand, in the second sensing mode, the amount of illumination light is reduced, so that the sensing light becomes relatively brighter, and the distal end of the insertion portion 20 can be separated from the observation target than in the first sensing mode. On the other hand, in the second sensing mode, the distant view is darker than in the first sensing mode, and it is difficult to grasp the surrounding situation.

  The surgeon observes the body cavity in the normal observation mode. When an observation target such as a tumor or ulcer is found, the imaging mode is switched to the first sensing mode or the second sensing mode, and the size of the observation target is measured. At this time, by appropriately using each sensing mode according to the situation, the size of the observation target can be efficiently measured.

  The insertion portion 20 is formed in a narrow tube having a diameter of about 10 mm, and is composed of a distal end portion 26, a bending portion 27, and a flexible tube portion 28 in order from the distal end. The tip portion 26 is formed of a hard resin material. An observation window 40 (see FIG. 2) for capturing image light from the observation target is provided on the distal end surface 26a of the distal end portion 26. The flexible tube portion 28 is formed in a thin and long tubular shape and has flexibility, and connects the operation portion 22 and the bending portion 27.

  The bending portion 27 is configured to bend up, down, left, and right according to the rotation operation of the up / down operation knob 30 and the left / right operation knob 31 provided in the operation unit 22. Inside the operation unit 22, there are provided a pulley that rotates following the rotation operation of the up / down operation knob 30 and a pulley that rotates following the rotation operation of the left / right operation knob 31. A wire is wound around each pulley. Both ends of each wire are connected to the bending portion 27, and push and pull the bending portion 27 following the rotation of each pulley accompanying the rotation operation of each knob 30, 31.

  Thereby, when the up / down operation knob 30 is rotated, the bending portion 27 is bent in the up / down direction, and when the left / right operation knob 31 is rotated, the bending portion 27 is bent in the left / right direction. The surgeon rotates the knobs 30 and 31 to bend the bending portion 27 and directs the observation window 40 provided on the distal end surface 26a in an arbitrary direction, thereby observing the inside of the body cavity.

  In addition to the knobs 30 and 31, the operation unit 22 includes a treatment instrument insertion port 32 for inserting a treatment instrument such as forceps and a snare, an air / water supply button 33 for performing air / water supply, and an electronic endoscope. A mode switching button 34 for switching the three shooting modes of the mirror 10 is provided. The mode switching button 34 is a two-stage push button. When the mode switching button 34 is not operated, the photographing mode of the electronic endoscope 10 is set to the normal observation mode. When the mode switching button 34 is pressed in one step, the shooting mode is switched from the normal observation mode to the first sensing mode, and when the mode switching button 34 is pressed in two steps, the shooting is switched from the first sensing mode to the second sensing mode. The mode is switched.

  The end of the universal cord 24 opposite to the operation unit 22 has a first connector 36 for taking in light and air supplied from the processor device 12 and a second connector used for transmitting power and various control signals. 37 is provided. The electronic endoscope 10 is detachably connected to the processor device 12 through these connectors 36 and 37.

  The first connector 36 is provided with a joint to which an air / water supply tube 38 is detachably connected. The water supply tank 16 is connected to the first connector 36 via the air / water supply tube 38. The air supplied from the processor device 12 is sent to an air supply channel formed in the electronic endoscope 10 via the first connector 36 and also to an air supply / water supply tube 38. In the air / water supply tube 38, an air supply line that sends air supplied from the processor device 12 to the water supply tank 16 and applies pressure to the water supply tank 16, and an inside of the water supply tank 16 that is pushed out by the applied pressure. And a water pipe for feeding out the water. This pipe for water supply is connected to a water supply channel formed in the electronic endoscope 10 by the first connector 36.

  The air supply channel and the water supply channel of the electronic endoscope 10 are closed by a valve that is interlocked with the pressing operation of the air / water supply button 33. The air / water supply button 33 is a two-stage push button. The valve switches between closing and opening of each channel in accordance with the pressing operation of the air / water supply button 33. When the air supply / water supply button 33 is pressed one step, the air supply channel is opened, and the air supplied from the processor device 12 is discharged from the distal end portion 26. When the air / water button 33 is pressed in two stages, the air supply channel is closed, the water supply channel is opened, and the water delivered from the water supply tank 16 is discharged from the tip end portion 26.

  As shown in FIG. 2, the distal end surface 26a of the distal end portion 26 has an observation window 40 for capturing image light from the observation target, and first and second two for irradiating illumination light and sensing light. Illumination windows 42, 44, a treatment instrument outlet 46 that exposes the distal end of the treatment instrument inserted into the treatment instrument insertion port 32, and an air / water supply nozzle 48 that discharges air or water in response to a pressing operation of the air / water supply button 33. And are provided.

  The observation window 40 and the illumination windows 42 and 44 are openings formed in a substantially circular shape. Each of the windows 40, 42, 44 is fitted with a cover glass 40a, 42a, 44a having translucency so as to be substantially flush with the tip surface 26a.

  The illumination windows 42 and 44 are disposed so as to be substantially symmetrical with respect to the observation window 40 with the observation window 40 interposed therebetween. By arranging the two illumination windows 42 and 44 in this way and irradiating substantially equal amounts of illumination light from the illumination windows 42 and 44, the entire observation region of the observation window 40 is illuminated uniformly and observed. It is possible to suppress uneven illumination in the region. Further, the distance d1 between the centers of the illumination windows 42 and 44 is about 6 mm.

  The air / water nozzle 48 is formed so that the air or water to be discharged is directed toward the observation window 40. Thereby, the observation window 40 is washed with water discharged from the air / water supply nozzle 48, and blood, mucus, and the like attached to the observation window 40 can be washed away.

  3 is a cross-sectional view schematically showing a cross section of the distal end portion 26 cut along the line Aa in FIG. 2 (a line passing through the centers of the illumination windows 42 and 44). As shown in FIG. 3, an observation optical system 50 and an image sensor 52 are provided in the back of the cover glass 40 a fitted in the observation window 40. The observation optical system 50 is configured by combining a plurality of lenses, and forms image light incident through the observation window 40 on the imaging surface of the image sensor 52. The image sensor 52 images the image light formed by the observation optical system 50 and outputs an image signal corresponding to the image light. The image sensor 52 is electrically connected to the second connector 37 via wiring. The image sensor 52 is electrically connected to the processor device 12 via the second connector 37.

  The processor device 12 performs image processing on the imaging signal output from the image sensor 52, encodes it into a video signal such as a composite signal or a component signal, and outputs the video signal to the monitor 14. As a result, an endoscopic image 70 (see FIG. 6) obtained by imaging the patient's body cavity or the like is displayed on the monitor 14. As the image sensor 52, for example, a CCD image sensor or a CMOS image sensor is used.

  A first illumination optical system 54 and a first light guide 55 are provided in the back of the cover glass 42 a fitted in the first illumination window 42. Similarly, a second illumination optical system 56 and a second light guide 57 are provided in the back of the cover glass 44 a fitted in the second illumination window 44. Each of the light guides 55 and 57 is formed by bundling a number of flexible optical fibers. Each light guide 55, 57 has one end face facing each illumination optical system 54, 56, passes through the insertion part 20, the operation part 22, and the universal cord 24, and the other end face from the first connector 36. It is exposed. Each of the light guides 55 and 57 causes the other end surface to face the light emitting surface provided in the processor device 12 when the first connector 36 is connected to the processor device 12.

  As a result, the light supplied from the processor device 12 is guided by the light guides 55 and 57 and enters the illumination optical systems 54 and 56. At this time, the light supplied from each of the light guides 55 and 57 has a spread angle of about ± 30 degrees around the optical axis. Each illumination optical system 54, 56 generates illumination light and sensing light based on the light incident from each light guide 55, 57, and the shooting mode of the electronic endoscope 10 when the mode switching button 34 is pressed. Each light is emitted from each of the illumination windows 42 and 44 according to the setting.

  As shown in FIGS. 4 and 5, the first illumination optical system 54 generates an illumination light and a sensing light and irradiates the first illumination window 42, and the illumination lens 60 irradiates the first illumination optical system 54. A transmissive liquid crystal module (light amount adjusting means) 62 for adjusting the amount of illumination light and an aperture mechanism (sensing light irradiation switching means) 64 for switching between irradiation / non-irradiation of sensing light are configured. These parts are arranged such that their optical centers coincide with the optical axis of the first light guide 55. Note that the configuration of the second illumination optical system 56 is the same as the configuration of the first illumination optical system 54, and therefore the description of the configuration of the second illumination optical system 56 is omitted.

  The irradiation lens 60 is configured by combining two lenses, a first lens 66 and a second lens 68. The first lens 66 is formed in a disc shape. A concave surface (first curved surface) 66b that is recessed in a substantially hemispherical shape is formed at the center of the back surface 66a of the first lens 66 on which light supplied from the first light guide 55 is incident. The concave surface 66b has a disk-like outer shape when viewed from the optical axis direction, and the first lens 66 is a plano-concave lens by the concave surface 66b.

  The second lens 68 is formed in a ring shape having a substantially circular through hole 68a at the center of the disk. The outer diameter of the second lens 68 is substantially the same as the diameter of the first lens 66. The inner diameter of the second lens 68 (the diameter of the through hole 68a) is slightly larger than the diameter of the concave surface 66b. The front surface of the second lens 68 that faces the first lens 66 is a flat surface. On the other hand, the back surface (second curved surface) 68b of the second lens 68 on which the light supplied from the first light guide 55 enters is formed in a curved surface bent with a predetermined curvature. The back surface 68b has an annular outer shape when viewed from the optical axis direction, and the second lens 68 is a ring-shaped plano-convex lens by the curved back surface 68b.

  In each of the lenses 66 and 68, the back surface 66a of the first lens 66 and the front surface of the second lens 68 are in contact with each other, and the optical axis of the first lens 66 and the optical axis of the second lens 68 are substantially coaxial. Combined. Thereby, the concave surface 66b is exposed through the through hole 68a, and the concave surface 66b is surrounded by the back surface 68b.

  The irradiation lens 60 has a predetermined spread angle so that the central portion of the light supplied from the first light guide 55 is incident on the concave surface 66b through the through hole 68a and the outer peripheral portion is incident on the back surface 68b. The distance from the first light guide 55 and the outer diameters of the lenses 66 and 68 are determined (see FIG. 5B).

  When the light from the first light guide 55 is incident, the concave surface 66b diffuses the light by increasing the spread angle of the light. The first lens 66 causes the light diffused by the concave surface 66b to enter the first illumination window 42 as illumination light. On the other hand, when the light from the first light guide 55 is incident, the back surface 68b converts the light into a parallel light flux. The second lens 68 uses the light converted into the parallel light flux by the back surface 68 b as sensing light, and enters the first illumination window 42 via the first lens 66. At this time, since the sensing light is incident on the back surface 66a, which is a flat surface, the sensing light travels straight through the first lens 66 without being diffused by the concave surface 66b.

  The physical quantities in the embodiment of FIG. The curvatures of the concave surface 66b and the back surface 68b may be appropriately designed according to the distance from the first light guide 55, the spread angle of light supplied from the first light guide 55, and the like.

  Further, in order to prevent refraction and reflection of the sensing light on the back surface 66a, it is preferable to use optical glass or optical plastic having substantially the same refractive index and dispersion for the lenses 66 and 68, and use the same material. Is most preferred.

  The transmissive liquid crystal module 62 is formed in a disc shape. The outer diameter of the transmissive liquid crystal module 62 is substantially the same as the diameter of the through hole 68 a of the second lens 68. The thickness of the transmissive liquid crystal module 62 is substantially the same as the thickness of the second lens 68. Thereby, the transmissive liquid crystal module 62 is incorporated in the second lens 68 so as to be fitted into the through hole 68a.

  The transmissive liquid crystal module 62 has a function of arbitrarily changing the transmittance by changing the alignment direction of the liquid crystal molecules. The transmissive liquid crystal module 62 adjusts the amount of illumination light emitted from the first lens 66 by changing the transmittance and changing the amount of light incident on the concave surface 66b.

  The diaphragm mechanism 64 has a plurality of diaphragm blades (light shielding members) 64a, and changes the area of the opening 64b provided in the center by driving each diaphragm blade 64a. The diaphragm mechanism 64 is disposed between the first light guide 55 and the irradiation lens 60. Each diaphragm blade 64a has a first position (a position shown in FIG. 5A) that prevents light from the first light guide 55 from entering the second lens 68 according to the driving of the diaphragm mechanism 64. It moves between a second position (a position shown in FIG. 5B) that allows light from the first light guide 55 to enter the second lens 68. The diaphragm mechanism 64 switches irradiation / non-irradiation of the sensing light by moving each diaphragm blade 64a to each position and causing the light from the first light guide 55 to enter or be shielded from the second lens 68.

  The transmissive liquid crystal module 62 is electrically connected to the mode switching button 34 and changes the transmittance according to the pressing operation of the mode switching button 34. Similarly, the diaphragm mechanism 64 is also electrically connected to the mode switching button 34. The diaphragm mechanism 64 moves each diaphragm blade 64a to each position in accordance with the pressing operation of the mode switching button 34. The transmissive liquid crystal module 62 and the aperture mechanism 64 may be directly connected to the mode switching button 34 or may be connected via a control unit such as a CPU.

  The transmissive liquid crystal module 62 sets the transmittance to almost 100% when the mode switching button 34 is not pressed and when the mode switching button 34 is pressed by one step, and the mode switching button 34 is pressed by two steps. When operated, the transmittance is changed to an arbitrary transmittance of 100% or less.

  Further, the diaphragm mechanism 64 moves each diaphragm blade 64a to the first position when the mode switching button 34 is not pressed, and when the mode switching button 34 is pressed one step, and when the mode switching button 34 is pressed. When the two-stage pressing operation is performed, each diaphragm blade 64a is moved to the second position.

  Accordingly, when the mode switching button 34 is not pressed, only the illumination light generated based on the light transmitted through the transmissive liquid crystal module 62 with a transmittance of almost 100% is emitted from the first illumination window 42. As described above, the photographing mode of the electronic endoscope 10 is set to the normal observation mode as described above.

  When the mode switching button 34 is pressed down by one step, the sensing light and the illumination light having the same light amount as in the normal observation mode are emitted from the first illumination window 42. The imaging mode of the endoscope 10 is set to the first sensing mode.

  Further, when the mode switching button 34 is pressed in two steps, the sensing light and the illumination light dimmed by the transmissive liquid crystal module 62 are emitted from the first illumination window 42. As described above, the photographing mode of the electronic endoscope 10 is set to the second sensing mode.

  FIG. 6 shows an example of an endoscopic image 70 displayed on the monitor 14. The endoscopic image 70 is provided with an image display area 70a that displays an image captured by the image sensor 52, and a mask area 70b that covers an excess portion of the captured image.

  When the photographing mode of the electronic endoscope 10 is set to the normal observation mode, illumination light is emitted from each of the illumination windows 42 and 44. The illumination light is diffused by the concave surface 66b, and uniformly illuminates the entire observation region of the observation window 40. Thereby, in the normal observation mode, as shown in FIG. 6A, an endoscopic image 70 having no illumination unevenness is acquired over the entire image display region 70a.

  When the photographing mode of the electronic endoscope 10 is set to the first sensing mode, the sensing light and the illumination light having the same light amount as that in the normal observation mode are emitted from the illumination windows 42 and 44, respectively. Since the sensing light is converted into a parallel light flux by the back surface 68b and travels straight without almost diffusing, the portion irradiated with the sensing light to be observed has higher luminance than the portion irradiated with only the illumination light. Thereby, in the first sensing mode, as shown in FIG. 6B, the first light spot 72 by the sensing light from the first illumination window 42 and the second light spot by the sensing light from the second illumination window 44 are obtained. 74 is acquired in the image display area 70a.

  The distance d2 between the centers of the light spots 72 and 74 is the same as the distance d1 between the centers of the illumination windows 42 and 44 (in this example, 6 mm). Therefore, by comparing the distance d2 between the centers of the light spots 72 and 74 and the observation target on the endoscopic image 70, the size of the observation target can be roughly measured.

  When the photographing mode of the electronic endoscope 10 is set to the second sensing mode, the sensing light and the reduced illumination light are emitted from the illumination windows 42 and 44, respectively. As a result, in the second sensing mode, the far view is darker than the endoscopic image 70 acquired in the first sensing mode, and the endoscopic image 70 in which the light spots 72 and 74 are emphasized is acquired.

  FIG. 7 is a luminance distribution graph in which the position on the line connecting the centers of the light spots 72 and 74 (on the line indicated by B-b in FIG. 6B) is plotted on the horizontal axis and the luminance on the line is plotted on the vertical axis. is there. FIG. 7 shows a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 5 mm and the observation target is observed in the first sensing mode.

  In the luminance distribution graph, a first luminance peak P1 corresponding to the first light spot 72 and a second luminance peak P2 corresponding to the second light spot 74 are generated. If the luminance difference between the peaks P1 and P2 and the valley V generated between them is small, it becomes difficult to determine the centers of the light spots 72 and 74, and the distance d2 between the centers of the light spots 72 and 74 is measured. Becomes difficult. For this reason, in order to accurately measure the center-to-center distance d2 between the light spots 72 and 74, it is preferable that the luminance difference between the peaks P1 and P2 and the valley portion V is twice or more.

  In FIG. 7, the luminance difference between the peaks P1 and P2 and the valley V is approximately doubled. Therefore, when the distance between the tip surface 26a and the observation target is 5 mm, the center-to-center distance d2 between the light spots 72 and 74 can be accurately measured in the first sensing mode.

  FIG. 8 is a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 10 mm and the observation target is observed in the first sensing mode. In FIG. 8, the luminance difference between the peaks P1 and P2 and the valley portion V is narrowed to be twice or less. Therefore, when the distance between the distal end surface 26a and the observation target is 10 mm, it is difficult to accurately measure the center distance d2 between the light spots 72 and 74 in the first sensing mode.

  FIG. 9 is a luminance distribution graph of the endoscopic image 70 when the observation target is observed in the second sensing mode while the distance between the distal end surface 26a and the observation target is set to 10 mm. At this time, the transmittance of the transmissive liquid crystal module 62 was set to 20%. In FIG. 9, the luminance difference between the peaks P1 and P2 and the valley V is twice or more again. Therefore, in the second sensing mode, the center-to-center distance d2 between the light spots 72 and 74 can be accurately measured even when the distance between the distal end surface 26a and the observation target is 10 mm.

  In addition, as apparent from FIGS. 8 and 9, in the second sensing mode in which the amount of illumination light is reduced, the overall luminance is lower than in the first sensing mode. Thus, in the second sensing mode, the surroundings are darker than in the first sensing mode, so it is difficult to grasp the surrounding situation.

  FIG. 10 is a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 15 mm and the observation target is observed in the second sensing mode. In FIG. 10, the luminance difference between each of the peaks P1 and P2 and the valley V is twice or more. Therefore, when the distance between the tip surface 26a and the observation target is 15 mm, the center-to-center distance d2 between the light spots 72 and 74 can be accurately measured in the second sensing mode.

  FIG. 11 is a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 20 mm and the observation target is observed in the second sensing mode. In FIG. 11, the luminance difference between each of the peaks P1 and P2 and the valley portion V is narrowed to be twice or less. Therefore, when the distance between the distal end surface 26a and the observation target is 20 mm or more, it is difficult to accurately measure the center-to-center distance d2 between the light spots 72 and 74 even if the second sensing mode is set.

  That is, in the electronic endoscope 10 of the present embodiment, when the distance between the distal end surface 26a and the observation target is in the range of 5 to 15 mm, the distance d2 between the centers of the light spots 72 and 74 is accurately measured. Can do. And since the illumination lens 60 which produces | generates illumination light and sensing light was provided in each illumination optical system 54 and 56, and both illumination light and sensing light were irradiated from each illumination window 42 and 44, sensing There is no need to separately provide a light guide or light source for light. Therefore, according to the present embodiment, the size of the observation object can be measured in a non-contact manner without causing an increase in the diameter of the insertion portion 20.

  In the present embodiment, the transmissive liquid crystal module 62 and the diaphragm mechanism 64 are provided in the illumination optical systems 54 and 56, respectively, and can be switched to three photographing modes of the normal observation mode, the first sensing mode, and the second sensing mode. Since it did in this way, observation of an observation object and measurement of the size of an observation object can be performed efficiently by using each photography mode properly.

  In the above embodiment, the ring-shaped second lens 68 having the through-hole 68a is shown. However, the shape of the second lens 68 is not limited to this, and is configured as an irradiation lens 80 shown in FIG. 12, for example. May be. The second lens 82 of the irradiation lens 80 is formed in a disk shape having substantially the same outer diameter as the first lens 66. The front surface of the second lens 82 that faces the first lens 66 is a flat surface. On the other hand, the back surface of the second lens 82 on which the light supplied from the first light guide 55 enters is a flat surface portion 82a formed on a plane substantially parallel to the front surface, and a curved surface portion formed on the outer periphery of the flat surface portion 82a. 82b. The flat portion 82a is formed in a circular shape having substantially the same diameter as the concave surface 66b.

  The second lens 82 is arranged so that the outer peripheral portion of the light supplied from the respective light guides 55 and 57 is incident on the curved surface portion 82b with a predetermined divergence angle. As a result, the central portion of the light supplied from the light guides 55 and 57 to the second lens 82 passes through the flat portion 82a having no curvature and enters the concave surface 66b of the first lens 66. And the outer peripheral part of the light supplied to the 2nd lens 82 from each light guide 55 and 57 is converted into a parallel light beam by the curved surface part 82b, permeate | transmits the 1st lens 66, and each illumination window 42 and 44 as sensing light. Is incident on. Therefore, even when the disc-shaped second lens 82 is used, the same effect as in the above embodiment can be obtained.

  In the above embodiment, the irradiation lens 60 composed of the two lenses of the first lens 66 and the second lens 68 is shown. However, the present invention is not limited to this, and as shown in FIG. It is good. The irradiation lens 84 is formed in a shape in which the lenses 66 and 68 of the above embodiment are integrated, and a first curved surface 84a that is recessed in a substantially hemispherical shape, and a second curved surface 84b in which the back surface is bent with a predetermined curvature. And have.

  In this way, if the irradiation lens 84 having a single lens structure is used, the same effects as those of the above-described embodiment can be obtained, and the trouble of combining a plurality of lenses can be saved, so that the assembling process can be simplified and the assembling can be performed. Cost can be reduced. However, when the irradiation lens 84 having a single structure having the curved surfaces 84a and 84b is used, the shape becomes complicated and the manufacturing cost of the irradiation lens 84 may increase. Therefore, it is only necessary to appropriately determine whether the irradiation lens has a single lens structure or a plurality of lens elements in consideration of total cost, assembling ability, and the like.

  In the above embodiment, the irradiation lens 60 including the first lens 66 having a plano-concave lens shape and the second lens 68 having a plano-convex lens shape is shown, but the lens configuration of the irradiation lens 60 is not limited to this, For example, you may comprise like the irradiation lens 86 shown in FIG.

  The irradiation lens 86 includes a first lens 87 having a plano-convex lens shape and a second lens 88 having a plano-convex lens shape. The first lens 87 is formed in a substantially cannonball shape, and has a first curved surface 87 a that protrudes in a hemispherical shape on the surface facing the first light guide 55. The first lens 87 becomes a plano-convex lens by the first curved surface 87a. The second lens 88 is formed in a substantially cylindrical shape, and has a second curved surface 88a bent at a predetermined curvature on the surface facing the first light guide 55, like the second lens 68 of the above embodiment. ing. The second lens 88 becomes a plano-convex lens by the second curved surface 88a.

  The inner diameter of the second lens 88 is formed substantially the same as the outer diameter of the first lens 87. The irradiation lens 86 is combined by inserting the first lens 87 into the second lens 88. Accordingly, the second lens 88 is concentric with the first lens 87. The irradiation lens 86 has the same center axis (optical axis) as the first light guide 55, the central portion of the light supplied from the first light guide 55 is incident on the first lens 87, and the outer peripheral portion is the first light guide. It arrange | positions so that it may inject into 2 lens 88. FIG.

  With the arrangement as described above, the first lens 87 diffuses the central portion of the light supplied from the first light guide 55 on the first curved surface 87a and irradiates the first illumination window 42 as illumination light. The second lens 88 converts the outer peripheral portion of the light supplied from the first light guide 55 into a parallel light beam by the second curved surface 88a, and irradiates the first illumination window 42 as sensing light.

  The physical quantities in the embodiment of FIG. 14 are shown in Tables 3 and 4 below. The aspherical surface of the first curved surface 87a is expressed by the following formula 1.

The aspheric coefficient is represented by P = 0.2394, E = −0.67356 × 10 ⁻¹ , F = 0.3223 × 10 ⁻¹ , and f = 1. Where x and h are coordinate values when the optical axis is the x axis, the object side is in the negative direction, and the h axis is the direction perpendicular to the x axis with the intersection of the aspherical surface and the optical axis as the origin. The reciprocal of the radius of curvature of the circle in contact with the aspherical surface in the vicinity of the optical axis, P is the conic constant, E, F, G... Are aspherical coefficients of the 4th order, 6th order, 8th order,. This is the focal length of an optical system having a curvature of a circle in contact with an aspheric surface in the vicinity. When the irradiation lens 86 is used, it is preferable to dispose the transmissive liquid crystal module 62 so as to be in contact with the front surface of the first lens 87 formed in a planar shape.

  When the illumination light is emitted from the illumination windows 42 and 44 using the illumination lens 86, as shown in FIG. 15, the first light spot 90 by the sensing light from the first illumination window 42 and the second illumination window The second light spot 92 by the sensing light from 44 has a donut shape. Even in such a donut-shaped spot, the distance d3 between the centers of the light spots 90 and 92 is the same as the distance d1 between the centers of the illumination windows 42 and 44 (in this example, 6 mm). Therefore, by comparing the distance d3 between the centers of the light spots 90 and 92 and the observation object on the endoscopic image 70, the size of the observation object can be roughly measured.

  FIG. 16 is a luminance distribution graph on the line connecting the centers of the light spots 90 and 92 (on the line indicated by Cc in FIG. 15). FIG. 16 shows a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 10 mm and the observation target is observed in the second sensing mode.

  Since each of the light spots 90 and 92 has a donut shape, the luminance distribution graph has two luminance peaks P1a and P1b and a valley V1 corresponding to the first light spot 90, and the second light spot. Corresponding to 92, two luminance peaks P2a and P2b and a valley V2 are generated. In this case, the center-to-center distance d3 can be measured by the distance between the valleys V1 and V2.

  As in the case of the circular light spots 72 and 74, in order to accurately measure the center-to-center distance d3, each peak P1a, P1b and valley V1 and each peak P2a, P2b and valley V2 It is preferable that the difference in luminance is 2 times or more. In FIG. 16, the respective luminance differences are approximately doubled. Therefore, when the distance between the distal end surface 26a and the observation target is 10 mm, the center-to-center distance d3 can be accurately measured.

  FIG. 17 is a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 20 mm and the observation target is observed in the second sensing mode. In FIG. 17, the luminance peaks P1b and P2a are overlapped due to light diffusion, but the luminance difference between each luminance peak and each valley V1, V2 is maintained at least twice. Therefore, in this example, the center-to-center distance d3 can be accurately measured even when the distance between the distal end surface 26a and the observation target is 20 mm. As described above, even with the irradiation lens 86 including the first lens 87 having a plano-convex lens shape and the second lens 88 having a plano-convex lens shape, the same effect as that of the above-described embodiment can be obtained.

  In the above embodiment, the illumination optical systems 54 and 56 including the transmissive liquid crystal module 62 as the light amount adjusting unit are shown. However, the present invention is not limited to this, and the illumination optical system 100 shown in FIG. . The illumination optical system 100 includes an irradiation lens 102, a light amount adjustment member 104, and a diaphragm mechanism 106.

  The irradiation lens 102 includes two lenses, a first lens 108 and a second lens 110. Similar to the first lens 66 of the above embodiment, the first lens 108 is a plano-concave lens in which a substantially hemispherical concave surface 108b is formed on the back surface 108a. The second lens 110 has a back surface 110a that swells in a curved shape. The back surface 110a has a disk-like outer shape when viewed from the optical axis direction, and the second lens 110 is a plano-convex lens by the back surface 110a. The lenses 108 and 110 are arranged at a predetermined interval.

  The aperture mechanism 106 has a plurality of aperture blades 106a, and drives the aperture blades 106a to change the area of the opening 106b provided at the center. Note that the configuration of the aperture mechanism 106 is the same as that of the aperture mechanism 64 of the above embodiment, and thus detailed description thereof is omitted.

  The light amount adjusting member 104 has a main body portion 112 formed in a substantially fan-shaped thin plate. A round bar-like swing shaft 114 is provided at the narrow end of the main body 112. The main body 112 is formed of a light-shielding material or painted with a light-shielding paint so as not to transmit light. The swing shaft 114 is attached so as to be substantially orthogonal to the main body portion 112. The light quantity adjusting member 104 is held so as to be swingable through the swing shaft 114.

  The main body portion 112 is provided with first and second light transmitting portions 116 and 118. Each of the translucent portions 116 and 118 is formed in a circular shape having substantially the same diameter as each of the lenses 108 and 110, and is arranged so that the respective centers are located on the same circle with the swing shaft 114 as the center. Yes. The first light transmitting portion 116 has a transmittance of almost 100% and transmits incident light as it is.

  On the other hand, the second light transmitting portion 118 is provided with a light transmitting region 118a having a transmittance of approximately 100% and a light reducing region 118b having a transmittance of approximately 20%. The light attenuation region 118b is a so-called ND filter, and the second light transmission unit 118 transmits the light incident on the light transmission region 118a as it is, and reduces the light incident on the light attenuation region 118b. The dimming region 118 b has a diameter substantially the same as the concave surface 108 b of the first lens 108 and is formed in a circular shape that is coaxial with the second light transmitting portion 118.

  When the main body 112 is sandwiched between the lenses 108 and 110 and swings around the swinging shaft 114, the light intensity adjusting member 104 is placed on the optical axis of the lenses 108 and 110. It arrange | positions so that it may be located in. Therefore, the distance between the lenses 108 and 110 may be set so as not to interfere with the light amount adjusting member 104 that swings between them, and the gaps generated between the light amount adjusting member 104 and the lenses 108 and 110 are reduced by about each. It is preferable to set it to 0.15 mm.

  The physical quantities of the embodiment in FIG. 18 are shown in Tables 5 and 6 below. If different materials are used for the translucent portions 116 and 118, there is a concern that the optical path length may change when they are arranged on the optical axes of the lenses 108 and 110, respectively. Therefore, it is preferable to use the same material for each of the light transmitting portions 116 and 118 so that the optical path length does not change.

  A swing mechanism 120 for swinging the light amount adjusting member 104 is connected to the swing shaft 114. The swing mechanism 120 swings the light amount adjusting member 104 around the swing shaft 114, whereby the first light transmitting portion 116 is positioned at the first position on the optical axes of the lenses 108 and 110 (FIG. 19 ( a)) and the second light transmitting portion 118 moves the light amount adjusting member 104 between the second position (see FIG. 19B) located on the optical axis of each lens 108, 110. The swing mechanism 120 may be a known mechanism including a motor and a gear.

  The swing mechanism 120 is electrically connected to the mode switching button 34. The swing mechanism 120 moves the light amount adjusting member 104 to the first position when the mode switching button 34 is not pressed and when the mode switching button 34 is pressed by one step. When the two-step pressing operation is performed, the light amount adjusting member 104 is moved to the second position.

  When the light amount adjusting member 104 is in the first position, the first light transmitting portion 116 is disposed between the lenses 108 and 110, and the light supplied from the light guide is directly applied to the entire back surface 108a of the first lens 108. Is incident on. On the other hand, when the light amount adjusting member 104 is in the second position, the second light transmitting portion 118 is disposed between the lenses 108 and 110, and the light incident on the concave surface 108b is attenuated by the dimming region 118b. .

  Thus, as in the above embodiment, when the mode switching button 34 is not pressed, the shooting mode is set to the normal observation mode, and when the mode switching button 34 is pressed one step, the shooting mode is changed. When the first sensing mode is set and the mode switching button 34 is pressed in two steps, the shooting mode is set to the second sensing mode.

  When the illumination light is irradiated from each illumination window 42, 44 using the illumination optical system 100, the light spot by each sensing light has a donut shape (see FIG. 15). FIG. 20 is a luminance distribution graph on a line connecting the centers of the respective light spots when the illumination optical system 100 is used. FIG. 20 shows a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 5 mm and the observation target is observed in the second sensing mode.

  Since each light spot has a donut shape, the luminance distribution graph has two luminance peaks P1a, P1b and a valley V1 corresponding to the first light spot, and also corresponds to the second light spot. Two luminance peaks P2a and P2b and a valley V2 are generated. In this case, the center-to-center distance can be measured by the distance between the valleys V1 and V2.

  FIG. 21 is a luminance distribution graph of the endoscopic image 70 when the distance between the distal end surface 26a and the observation target is set to 10 mm and the observation target is observed in the second sensing mode. In FIG. 21, although the donut shape has collapsed, the luminance difference between the luminance peak P3 corresponding to the first light spot and the luminance peak P4 corresponding to the second light spot and the valley V3 generated therebetween. Is twice or more, the center-to-center distance can be measured by the distance between the luminance peaks P3 and P4.

  As described above, even if the light attenuation region 118b, which is an ND filter, is arranged on the optical axis of each lens 108, 110 or retracted, the amount of illumination light can be adjusted. An effect can be obtained. The dimming region 118b is not limited to the ND filter, and a liquid crystal or the like may be used. Further, the configuration in which the dimming region 118b is arranged on the optical axis of each lens 108, 110 or retracted is not limited to the above. Further, in each of the above embodiments, the amount of illumination light is reduced in the second sensing mode. However, the present invention is not limited to this, and the illumination light may be completely blocked.

  In the above embodiment, the example in which the present invention is applied to the electronic endoscope 10 in which the light supplied from the processor device 12 is incident on the illumination optical systems 54 and 56 via the light guides 55 and 57 has been described. For example, as illustrated in FIG. 22, the first LED 130 that supplies light to the first illumination optical system 54 and the second LED 132 that supplies light to the second illumination optical system 56 are provided, as illustrated in FIG. The present invention may be applied to a light source built-in type electronic endoscope in which light is directly incident on each of the illumination optical systems 54 and 56 without going through the above.

  In the embodiment described above, the electronic endoscope 10 having the two illumination windows 42 and 44 is shown, but the number of illumination windows is not limited to two, and may be three or more. In the above embodiment, the cover glasses 42a and 44a are fitted into the respective illumination windows 42 and 44, and the respective illumination optical systems 54 and 56 are disposed behind the respective cover glasses 42a and 44a. For example, the first lens 66 of each illumination optical system 54, 56 may be directly exposed from each illumination window 42, 44.

  In the above-described embodiment, the diaphragm mechanism 64 is shown as the sensing light irradiation switching unit. However, the sensing light irradiation switching unit is not limited to this. For example, only the central portion of the light supplied from each of the light guides 55 and 57 is used. An aperture having an opening for transmission is arranged on the optical axis to prevent light from entering the second lens 68, or the aperture is retracted from the optical axis to prevent light from entering the second lens 68. It may be possible to switch irradiation / non-irradiation of sensing light by allowing it.

  In the above embodiment, an electronic endoscope is shown as an endoscope. However, the present invention is not limited to an electronic endoscope, and the present invention may be applied to other endoscopes such as an ultrasonic endoscope. . In the above-described embodiment, an example in which the present invention is applied to the medical electronic endoscope 10 has been described. However, the present invention may be applied to an industrial endoscope.

It is explanatory drawing which shows the structure of an endoscope system roughly. It is explanatory drawing which shows the structure of a front end surface roughly. It is explanatory drawing which shows schematically the internal structure of a front-end | tip part. It is a perspective view which shows the structure of an illumination optical system roughly. It is explanatory drawing which shows the structure of an illumination optical system roughly. It is explanatory drawing which shows an example of an endoscopic image. It is a luminance distribution graph of an endoscopic image when the distance between the distal end surface and the observation target is set to 5 mm and the observation target is observed in the first sensing mode. It is a luminance distribution graph of an endoscopic image when the distance between the distal end surface and the observation target is set to 10 mm and the observation target is observed in the first sensing mode. It is a brightness | luminance distribution graph of an endoscopic image at the time of observing the observation object in 2nd sensing mode, setting the distance of a front end surface and an observation object to 10 mm. It is a brightness | luminance distribution graph of an endoscopic image at the time of setting the distance of a front end surface and observation object to 15 mm, and observing the observation object in 2nd sensing mode. It is a luminance distribution graph of an endoscopic image when the distance between the distal end surface and the observation target is set to 20 mm and the observation target is observed in the second sensing mode. It is explanatory drawing which shows the example using a disk-shaped 2nd lens. It is explanatory drawing which shows the example using the irradiation lens of 1 sheet structure. It is explanatory drawing which shows the example using the irradiation lens which consists of a 1st lens of a plano-convex lens and a 2nd lens of a plano-convex lens. It is an example of the endoscopic image in which the donut-shaped light spot was projected. It is an example of the luminance distribution graph at the time of using a donut-shaped light spot. It is an example of the luminance distribution graph at the time of using a donut-shaped light spot. It is explanatory drawing which shows the example which arrange | positions ND filter on an optical axis and performs light quantity adjustment. It is explanatory drawing which shows the state which has arrange | positioned each translucent part on an optical axis. It is an example of the luminance distribution graph at the time of using an ND filter. It is an example of the luminance distribution graph at the time of using an ND filter. It is explanatory drawing which shows roughly the structure of the electronic endoscope with a built-in light source.

Explanation of symbols

2 Endoscope system 10 Electronic endoscope (endoscope)
DESCRIPTION OF SYMBOLS 20 Insertion part 42 1st illumination window 44 2nd illumination window 54 1st illumination optical system 56 2nd illumination optical system 60 Irradiation lens 62 Transmission type liquid crystal module (light quantity adjustment means)
64 Aperture mechanism (sensing light irradiation switching means)
64a Aperture blade (shading member)
66 First lens 66b Concave surface (first curved surface)
68 Second lens 68b Rear surface (second curved surface)
70 Endoscopic image 72 First light spot 74 Second light spot

Claims (5)

In an endoscope illumination optical system that generates illumination light for illuminating an observation object from incident light incident with a predetermined divergence angle, and irradiates from an illumination window provided at the distal end of the insertion portion.
A first curved surface that is formed in a disc shape so that a central portion of the incident light is incident thereon, generates the illumination light by diffusing the incident light, and has a diameter larger than the diameter of the first curved surface; A second curved surface that is formed in an annular shape or a disc shape so that the outer peripheral portion of the incident light is incident thereon, and generates sensing light for measuring the size of the observation object by converting the incident light into a substantially parallel light beam. And an illumination lens for irradiating both the illumination light and the sensing light from the illumination window.   2. The endoscope illumination optical system according to claim 1, wherein the irradiation lens includes a first lens in which the first curved surface is formed and a second lens in which the second curved surface is formed.   A light-shielding member that moves between a position that prevents the outer peripheral portion of the incident light from entering the second curved surface and a position that allows the incident to be incident; The illumination optics for an endoscope according to claim 1 or 2, further comprising sensing light irradiation switching means for switching irradiation / non-irradiation of the sensing light by making light incident on or blocking a curved surface. system.   4. The endoscope illumination optical system according to claim 1, further comprising a light amount adjusting unit configured to adjust a light amount of the illumination light irradiated from the irradiation lens. 5. A plurality of illumination windows provided at the tip of the insertion portion;
A plurality of illumination optical systems provided corresponding to each of the illumination windows, generating illumination light for illuminating an observation object from incident light incident with a predetermined spread angle, and irradiating from the corresponding illumination window And having
A plurality of sensing beams of substantially parallel light beams are irradiated from the tip of the insertion portion, and the distance between centers of a plurality of light spots formed on the observation target by each sensing light is compared with the observation target on the endoscopic image. In the endoscope that can measure the size of the observation object in a non-contact manner,
A first curved surface that is formed in a disc shape so that a central portion of the incident light is incident thereon, generates the illumination light by diffusing the incident light, and has a diameter larger than the diameter of the first curved surface; A second curved surface that is formed in an annular shape or a disk shape so that an outer peripheral portion of the incident light is incident thereon, and generates the sensing light by converting the incident light into a substantially parallel light beam, and the illumination light and the sensing An endoscope characterized in that each illumination optical system is provided with an illumination lens that irradiates both the light and the corresponding illumination window.

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