JP2012135432A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope in which light distribution of an illumination optical system can be switched by an easy control, and light supplied from a light source is efficiently used as illumination light.SOLUTION: An objective optical system 26, an illumination optical system 27a, 27b are disposed in a distal end 16a continuously prepared at an insertion part distal end of the endoscope. The illumination optical system 27a, 27b consist of an optical fiber 31a, 31b, and a liquid lens 40. The light led from a light source to the optical fiber 31a, 31b is supplied to the liquid lens 40. The Illumination optical system 27a, 27b irradiate illumination light to a surface H of a subject by the liquid lens. Electrode members 44, 45 of the liquid lens 40 are impressed by voltage, thereby an illumination angle changes and an illumination angle of the illumination optical system 27a, 27b becomes a wide angle, and a light range Sof the illumination optical system 27a, 27b laps with an observation range Sof the objective optical system 26.

Description

  The present invention relates to an endoscope for irradiating illumination light to a site to be observed in a subject.

  An endoscope includes an observation optical system for capturing image light of a subject and an illumination optical system for irradiating the subject with illumination light at a distal end portion of an insertion portion to be inserted into the subject. Yes. The irradiation angle and optical axis direction of the illumination light by the illumination optical system are set so as to match the observation range by the observation optical system.

  In the conventional endoscope, the illumination angle of the illumination light by the illumination optical system and the optical axis direction are fixed. However, in the endoscope described in Patent Document 1, the light guide that guides the light supplied from the light source device is emitted. Between the end and the illumination window located on the most distal side of the illumination optical system, a pair of transparent members whose opposing surfaces are inclined with respect to the axial direction are arranged in a variable manner along the axial direction. By changing the interval between the transparent members, the direction of the optical axis of the illumination light is changed.

  In Patent Documents 2 and 3, an actuator that moves one of the illumination lenses constituting the illumination optical system along the optical axis direction is provided, and the actuator is driven to move the illumination lens along the optical axis direction. Describes a configuration for changing the light distribution characteristic of illumination light, that is, the irradiation angle at which high illuminance is applied. In Patent Document 3, the illumination lens is attached to the endoscope distal end so as to be swingable, and an actuator such as a piezoelectric element is driven to tilt the illumination lens so that the optical axis direction is tilted to the observation range.

  Patent Document 3 describes the configuration of an endoscope that includes a light distribution conversion filter formed of a liquid crystal filter or the like as a light distribution correction unit that switches a light distribution characteristic of illumination light by an illumination optical system. Such an endoscope is provided with a filter that transmits illumination light as it is, a filter that blocks ambient light, and the like, and switches the filter according to the surface condition of the observation site and the intention of the observer to provide light distribution characteristics. It is changing.

JP 2006-334043 A Japanese Patent Laid-Open No. 10-239740 JP-A-5-323211

  Endoscopes are required to obtain a clear observation image even when observation is performed with the distal end of the insertion portion approaching a few millimeters with respect to the surface of the subject. However, since the observation optical system and the illumination optical system are not provided coaxially in the endoscope, the observation range by the observation optical system and the illumination optics are increased as the distal end surface of the insertion portion of the endoscope is brought closer to the surface of the subject. Both the illumination ranges by the system are narrowed and do not overlap each other. Therefore, illumination light does not reach the observation range, and it may be difficult to obtain a clear observation image.

  Therefore, in order to solve the shortage of illumination light quantity in close-up observation, it is conceivable to use an illumination lens with a wide illumination angle as the illumination optical system. However, when using a wide-angle illumination lens, it enters the illumination lens. Since the rate at which light is lost without reaching the exit surface increases, the amount of illumination light applied to the subject decreases. Therefore, sufficient brightness cannot be obtained by normal observation. Further, since light lost in the wide-angle illumination lens is converted into heat on the outer peripheral surface, heat generation around the illumination lens becomes a problem. Alternatively, when the light amount of the light source itself is increased in order to compensate for the shortage of the light amount of the wide-angle illumination lens, the amount of light lost in the illumination lens also increases, which further raises the problem of heat generation.

  Therefore, as in the endoscopes described in Patent Documents 1 to 3, it is possible to cope with the shortage of the illumination light amount in the close-up observation by changing the light distribution characteristics such as the illumination angle of the illumination light and the optical axis direction. However, the mechanism for changing the distance between the pair of transparent members, or the mechanism for moving the illumination lens, etc., does not control the driving of the actuator that moves the transparent member or the illumination lens with high accuracy. Or the optical axis direction does not have a predetermined angle or orientation. Moreover, in order to control with high accuracy, the accuracy of each component is required, which causes an increase in the cost of the endoscope.

  In addition, in an endoscope including a light distribution correction filter as in Patent Document 3, a filter that transmits all of the illumination light is used during close-up observation, and the illumination range is smaller during normal observation than during close-up observation. In addition, it is conceivable to switch the filter so as to block the surrounding illumination light, but if the illumination light quantity is insufficient in the close-up observation, the illumination light quantity cannot be increased beyond the performance of the illumination optical system. A problem similar to that of a conventional endoscope occurs. Even if the light distribution correction filter of Patent Document 3 and a wide-angle illumination lens are combined, the above-described loss of light, insufficient light quantity, and heat generation of the illumination lens occur. Furthermore, if the surroundings are shielded by the light distribution correction filter during normal observation, the amount of illumination light decreases, so that a problem of insufficient light amount occurs as in the case of using the wide-angle illumination lens described above.

  The present invention has been made in view of the above-described problems, makes it possible to switch light distribution of an illumination optical system with simple control, and to efficiently use light supplied from a light source as illumination light. An object is to provide an endoscope.

  An endoscope according to the present invention includes an insertion portion that is inserted into a subject, a distal end portion of the insertion portion, an observation optical system that captures image light of the subject, and a liquid boundary surface. And an illumination optical system for irradiating the illumination light in a subject.

  In the liquid lens, it is preferable that the angle of irradiation by the illumination optical system is switched to a wider angle when approaching the observation optical system than when performing normal observation.

  The liquid lens is a liquid lens using an electrowetting phenomenon, and a substantially cylindrical case whose front end and base end are covered with a transparent cover, and a non-mixable conductive liquid and an insulation sealed in the case. A conductive liquid and a pair of electrodes that are arranged over the entire circumference of the base end and the distal end side of the conductive liquid and the insulating liquid and to which a voltage is applied, by applying a voltage to the electrode Preferably, the conductive liquid is attracted to one of the electrodes to change the curvature of the boundary surface between the conductive liquid and the insulating liquid to vary the irradiation angle.

  It is preferable that the liquid lens tilts the optical axis direction of the illumination optical system toward the observation range by the observation optical system when the observation optical system approaches.

  The liquid lens is a liquid lens using an electrowetting phenomenon, and a substantially cylindrical case whose front end and base end are covered with a transparent cover, and a non-mixable conductive liquid and an insulation sealed in the case. A conductive liquid and a pair of electrodes that are arranged at a base end and a distal end side of the conductive liquid and the insulating liquid and a part of the circumferential direction, and to which a voltage is applied, and by applying a voltage to the electrode Preferably, the conductive liquid is attracted to one of the electrodes, and the boundary surface between the conductive liquid and the insulating liquid is inclined to vary the optical axis direction.

  The pair of electrodes are preferably provided integrally with the case.

  The liquid lens includes a determination unit that determines whether or not the observation optical system has switched from normal observation to close-up observation, and when the determination unit determines that the observation optical system has switched from normal observation to close-up observation. It is preferable to apply a voltage to the illumination optical system so that the irradiation angle of the illumination optical system is switched to a wide angle, or to incline the optical axis direction toward the observation range by the observation optical system.

  A light amount detecting unit that detects an illumination light amount of an observation range in which image light is captured by the observation optical system, and the determination unit is configured to change the observation optical when the light amount detected by the light amount detection unit is switched from increase to decrease; It is preferable to determine that the system has switched from normal observation to close-up observation.

  According to the present invention, the illumination light is irradiated into the subject by the illumination optical system composed of the liquid lens that deforms the boundary surface of the liquid and varies the light distribution characteristic of the illumination light. The light distribution of the system can be switched, and the light supplied from the light source can be used efficiently as illumination light.

It is an external appearance perspective view of an endoscope system. It is a top view which shows the structure of the front-end | tip part of an electronic endoscope. It is sectional drawing of the front-end | tip part cut | disconnected along the illumination optical system and the observation optical system. It is sectional drawing which shows the structure of a liquid lens. It is a perspective view which shows the structure of the case of a liquid lens. It is sectional drawing which shows the state which varied the irradiation angle of the illumination optical system which consists of a liquid lens. It is a block diagram which shows the outline of the electrical constitution of an electronic endoscope system. It is a graph which shows the relationship between the distance from the front-end | tip of an insertion part to the surface of a subject, and illumination light quantity. It is sectional drawing which shows the structure of 2nd Embodiment which changes the direction of the optical axis of the illumination optical system which consists of a liquid lens. It is sectional drawing which shows the structure of the liquid lens which changes the direction of an optical axis. It is a perspective view which shows the structure of the case of the liquid lens which changes the direction of an optical axis.

  As shown in FIG. 1, the electronic endoscope system 10 includes an electronic endoscope 11, a processor device 12, a light source device 13, an air / water supply device 14, and the like. The air / water supply device 14 is built in the light source device 13 and is a well-known air supply device (pump or the like) 14a for supplying air, and a washing water tank that is provided outside the light source device 13 and stores washing water. 14b. The electronic endoscope 11 includes an insertion portion 16 to be inserted into a subject, an operation portion 17 connected to a proximal end portion of the insertion portion 16, and a connector 18 connected to the processor device 12 and the light source device 13. And a universal cord 19 that connects between the operation unit 17 and the connector 18.

  The insertion portion 16 is provided at the distal end thereof, and includes a distal end portion 16a having a built-in CCD type image sensor (see FIG. 3, hereinafter referred to as a CCD) 36 as an imaging element for imaging within the subject, and the distal end portion 16a. It comprises a bendable bending portion 16b provided continuously at the base end, and a flexible flexible tube portion 16c provided continuously at the base end of the bending portion 16b.

  The connector 18 is a composite type connector to which the processor device 12, the light source device 13, and the air / water supply device 14 are connected. The operation unit 17 includes an angle knob 20 for bending the bending portion 16b vertically and horizontally, and an air / water supply button 21 for ejecting air and water from an air / water supply nozzle 29 (see FIG. 2). An operating member is provided. The operation unit 17 is provided with a forceps port 22 for inserting a treatment tool such as an electric knife into a forceps channel (not shown).

  The processor device 12 is electrically connected to the light source device 13 and comprehensively controls the operation of the electronic endoscope system 10. The processor device 12 supplies power to the electronic endoscope 11 via the universal cord 19 and a transmission cable inserted into the insertion portion 16 and controls the driving of the CCD 36. In addition, the processor device 12 acquires an imaging signal output from the CCD 36 via a transmission cable, and performs various image processing to generate image data. The image data generated by the processor device 12 is displayed as an observation image on a monitor 23 connected to the processor device 12 by a cable.

  As shown in FIGS. 2 and 3, the distal end portion 16 a includes a distal end rigid portion 24, a distal end protective cap 25 attached to the distal end side of the distal end rigid portion 24, an objective optical system 26 (observation optical system), Illumination optical systems 27a and 27b, a forceps outlet 28, and an air / water supply nozzle 29 are provided. The distal end hard portion 24 is made of a metal such as stainless steel, and a plurality of through holes are formed along the longitudinal direction. Various parts such as the imaging unit 30, optical fibers 31a and 31b as light guides, and forceps channels (not shown) are fitted and fixed in the respective through holes of the distal end rigid portion 24. The rear end of the distal end rigid portion 24 is coupled to the distal bending piece 32 constituting the bending portion 16b. The outer tube 33 is covered on the outer periphery of the distal end hard portion 24.

  The tip protection cap 25 is made of rubber, resin, or the like, is a surface that is substantially orthogonal to the axial direction of the insertion portion 16, and is formed with a flat surface 25 a that constitutes the tip surface of the insertion portion 16. The tip protection cap 25 is formed with through holes 25b to 25e that expose the objective optical system 26, illumination optical systems 27a and 27b, and the air / water supply nozzle 29, and a forceps outlet 28. The pair of illumination optical systems 27a and 27b are arranged at symmetrical positions with the objective optical system 26 in between.

  As shown in FIG. 3, the imaging unit 30 includes an objective optical system 26 (observation optical system), a lens barrel 35 that holds the objective optical system 26, a CCD 36, and the like. The lens barrel 35 is attached to the distal end rigid portion 24 so that the optical axis of the objective optical system 26 is parallel to the central axis of the distal end portion 16a. The objective optical system 26 includes a lens group and a prism. Among the lens group, the lens 26 </ b> A located closest to the distal end is exposed from the through hole 25 b of the distal end protection cap 25. A CCD 36 is disposed on the exit end side of the objective optical system 26, and the image light in the observation range taken in by the objective optical system 26 is imaged on the light receiving surface (not shown) of the CCD 36 to be an imaging signal. Converted. The imaging signal output from the CCD 36 is transmitted to the processor device 12 via a signal cable.

  The illumination optical systems 27a and 27b irradiate the observation site in the subject with illumination light from the light source device 13. The forceps outlet 28 is connected to a forceps channel (not shown) disposed in the insertion portion 16 and communicates with the forceps port 22 of the operation portion 17.

  The illumination optical system 27a includes an optical fiber 31a that guides light from the light source device 13, and a liquid lens 40 that varies the light distribution characteristics of the illumination light using an electrowetting phenomenon. The illumination optical system 27b includes an optical fiber 31b and a liquid lens 40, and has the same configuration as the illumination optical system 27a.

  The liquid lens 40 faces the emission ends of the optical fibers 31a and 31b. The optical fibers 31a and 31b pass through the insertion portion 16, the operation portion 17, the universal cord 19, and the connector 18, and guide the illumination light from the light source device 13 to the liquid lens 40 to the observation site in the subject. . Light guided from the light source device 13 through the optical fibers 31 a and 31 b is irradiated to the subject as illumination light by the liquid lens 40.

  As shown in FIG. 4, the liquid lens 40 includes a case 41, and a conductive liquid 42 and an insulating liquid 43 that are sealed in the case 41 and do not mix with each other. For example, water is used as the conductive liquid 42 and oil is used as the insulating liquid 43.

  As shown in FIG. 5, the case 41 includes a first electrode member 44, a second electrode member 45, a seal member 46, and transparent covers 47 and 48 that are integrally provided. The first electrode member 44 is made of a conductive material such as metal, is formed in a substantially cylindrical shape, and an inner peripheral surface 44a (see FIG. 4) is a taper whose inner diameter gradually decreases from the distal end side toward the proximal end side. It is formed in a shape. A thin insulating film 49 is formed on the inner peripheral surface 44a and the front end surface 44b (see FIG. 4) of the first electrode member 44. Further, the first electrode member 44 is formed with a cover holding portion 44c that holds the transparent cover 47 on the proximal end side. The cover holding portion 44c is concave according to the outer shape of the disk-shaped transparent cover 47, and is formed in a concave shape with the proximal end facing the optical fiber 31a open.

  The second electrode member 45 is made of a conductive material such as metal, and includes a cylindrical portion 51 that covers the outer periphery of the first electrode member 44 and a distal end plate portion 52 that covers the distal end side. One electrode member 44 has an inner diameter larger than the outer diameter. The tip plate portion 52 is formed with a cover holding portion 52a that holds the transparent cover 48 on the tip side. The cover holding portion 52a is concave in accordance with the outer shape of the disc-shaped transparent cover 48, and is formed in a concave shape with the distal end located on the side opposite to the optical fiber 31a being opened.

  The second electrode member 45 is attached to the distal end side of the first electrode member 44 via the seal member 46 so that the central axes of the first electrode member 44 and each other are aligned. The seal member 46 is made of an insulating material such as rubber, is formed in a substantially cylindrical shape, and is sandwiched between the first and second electrode members 44 and 45 to insulate them.

  The first and second electrode members 44 and 45 are fixed with the seal member 46 interposed therebetween, and the transparent covers 47 and 48 are fixed to the cover holding portions 44c and 52a to seal the distal end and the proximal end. Case 41 is formed. When the first and second electrode members 44 and 45 are fixed to the seal member 46 and the cover holding portions 44c and 52a are fixed to the transparent covers 47 and 48, the adhesive is surely adhered by a method such as flowing an adhesive into the gap. It is preferable to do. The liquid lens 40 is attached with the case 41 sandwiched between the distal end rigid portion 24 of the distal end portion 16a and the distal end protective cap 25, and the transparent cover 48 is exposed from the through holes 25c and 25d. The transparent covers 47 and 48 are made of a transparent material such as quartz glass or sapphire glass.

  The conductive liquid 42 and the insulating liquid 43 are sealed at the distal end side and the proximal end side in the case 41, respectively. The insulating liquid 43 is disposed inside the first electrode member 44, specifically, an insulating film. The conductive liquid 42 is set to such an amount that it is in contact with the inner peripheral surface 45 a of the second electrode member 45 and a part of the insulating film 49. . As a result, the first and second electrode members 44 and 45 are disposed over the entire circumference of the conductive liquid 42 and the insulating liquid 43 at the distal end side and the proximal end side.

  The first and second electrode members 44 and 45 are connected to the processor device 12 via a wiring 53, and application of voltage is controlled by a controller 66 (see FIG. 7) of the processor device 12. During normal observation by the electronic endoscope system 10, when no voltage is applied to the first and second electrode members 44 and 45 of the liquid lens 40, as shown in FIG. 4, the first and second electrode members The boundary surface 54 between 44 and 45 is substantially planar (state indicated by a solid line in FIG. 4).

  When a predetermined voltage V is applied to the first and second electrode members 44 and 45 at the time of approaching observation in which the distal end (flat surface 25a) of the insertion portion 16 is close to the surface of the subject, the conductive liquid 42 is applied. Is drawn closer to one of the first electrode members 44. At this time, since the first and second electrode members 44 and 45 are disposed over the entire circumference of the conductive liquid 42 and the insulating liquid 43, the insulating properties that existed in the vicinity of the first electrode member 44. The liquid 43 is pushed out and tries to gather at the center of the case 41. Thereby, since the boundary surface 54 is curved and the refractive index of the illumination light is variable (a state indicated by a two-dot chain line in FIG. 4), the illumination angle of the illumination optical system 27a is a narrow angle during normal observation ( The irradiation angle is switched to a wider angle than the range indicated by the dotted line arrow in FIG. 4 (range indicated by the two-dot chain line arrow in FIG. 4). In the illumination optical system 27b, when a voltage is applied to the liquid lens 40, the illumination angle is similarly switched to a wide angle.

As shown in FIG. 6, the illumination optical system 27a in the nearby observation, 27b is, when switched to the wide angle illumination angle than the normal observation, the illumination optical system 27a, the illumination range S _L by 27b spread, the objective optical overlapping the observation range _{S O} by system 26.

  FIG. 7 shows an outline of the electrical configuration of the electronic endoscope system 10. The electronic endoscope 11 includes an AFE 60 and an imaging control unit 61 in addition to the illumination optical systems 27a and 27b and the imaging unit 30. The CCD 36 photoelectrically converts an image in the subject imaged on the imaging surface by the objective optical system 26, accumulates signal charges, and outputs the accumulated signal charges as an imaging signal. The output imaging signal is sent to the AFE 60. The AFE 60 includes a correlated double sampling (CDS) circuit, an automatic gain adjustment (AGC) circuit, an A / D converter, and the like (all not shown). The CDS performs correlated double sampling processing on the imaging signal output from the CCD 36 to remove noise generated by driving the CCD 36. The AGC amplifies the imaging signal from which noise has been removed by CDS.

  The imaging control unit 61 is connected to the controller 66 in the processor device 12 when the electronic endoscope 11 and the processor device 12 are connected, and sends a drive signal to the CCD 36 when an instruction is issued from the controller 66. . The CCD 36 outputs an imaging signal to the AFE 60 at a predetermined frame rate based on the drive signal from the imaging control unit 61.

  The processor device 12 includes a digital signal processing circuit (DSP) 62, a digital image processing circuit (DIP) 63, a display control circuit 64, a VRAM 65, a controller 66, an operation unit 67, and the like.

  The controller 66 controls the overall operation of the processor device 12. The DSP 62 performs various signal processing such as color separation, color interpolation, gain correction, white balance adjustment, and gamma correction on the imaging signal output from the AFE 60 of the electronic endoscope 11 to generate image data. The image data generated by the DSP 62 is input to the working memory of the DIP 63. Further, the DSP 62 generates ALC control data necessary for automatic control (ALC control) of the amount of illumination light, such as an average luminance value obtained by averaging the luminance of each pixel of the generated image data, and inputs the generated data to the controller 66.

  The DIP 63 performs various image processing such as electronic scaling, color enhancement processing, and edge enhancement processing on the image data generated by the DSP 62. Image data that has been subjected to various types of image processing by the DIP 63 is temporarily stored in the VRAM 65 as an observation image and then input to the display control circuit 64. The display control circuit 64 selects and acquires an observation image from the VRAM 65 and displays it on the monitor 23.

  The operation unit 67 includes a known input device such as an operation panel, a mouse, and a keyboard provided in the housing of the processor device 12. The controller 66 operates each unit of the electronic endoscope system 10 in accordance with operation signals from the operation unit 67 and the operation unit 17 of the electronic endoscope 11.

  The light source device 13 includes a light source 68, a condenser lens 69, and a light source control unit 70. The light source 68 is a white light source such as a xenon tube, and the white light supplied from the light source 68 is guided to the optical fiber 71 through the condenser lens 69 and the like. The optical fiber 71 is connected to the optical fibers 31 a and 31 b of the electronic endoscope 11 via the connector 18. For this reason, the white light emitted from the light source 68 is guided to the optical fibers 31 a and 31 b and enters the liquid lens 40. The liquid lens 40 irradiates the subject as illumination light. The light source control unit 70 adjusts the timing of turning on / off the light source 68 according to an adjustment signal or a synchronization signal input from the controller 66 of the processor device 12.

  The controller 66 also serves as a determination unit that determines whether or not the electronic endoscope 11 is performing close-up observation. For example, the controller 66 calculates an average luminance value obtained by averaging the luminance of each pixel of image data generated based on an imaging signal acquired from the electronic endoscope 11 as detection of the amount of illumination light in the observation range of the electronic endoscope 11. To do. Then, from the amount of illumination light detected from this imaging signal, the controller 66 determines whether or not the electronic endoscope 11 is performing close observation.

  The determination made by the controller 66 is performed as follows. When the inside of the subject is observed with the electronic endoscope 11, the relationship between the distance from the distal end (flat surface 25a) of the insertion portion 16 to the surface H of the subject and the amount of illumination light is as shown in FIG. When the insertion portion 16 is inserted into the subject and the electronic endoscope 11 performs normal observation, when the insertion portion 16 is further pushed into the close-up observation, that is, the flat surface 25a is the surface of the subject. When approaching H gradually, first, the reflected light from the subject increases, so that the amount of illumination light captured by the objective optical system 26 increases, and then the illumination range becomes narrower. Decrease. That is, the time when the illumination light quantity is increased to the state where the illumination light quantity is reduced is when the normal observation is shifted to the close observation. From this, the controller 66 determines that the close observation is performed after passing the peak value P where the illumination light quantity switches from increase to decrease, and otherwise determines that the normal observation is performed.

  When it is determined that the approach observation is performed, the controller 66 controls the power supply circuit (not shown) to supply power to the electronic endoscope 11 and apply a voltage to the liquid lens 40. As a result, the liquid lens 40 changes so that the boundary surface is curved, and the illumination light changes to a wide angle.

  The operation of the above configuration will be described. When the insertion portion 16 is inserted into the subject and the subject is being observed with the electronic endoscope 11, the flat surface 25a is close to the surface H of the subject and the illumination range by the illumination optical systems 27a and 27b. In addition, the observation range by the objective optical system 26 becomes narrow, and the observation image may become dark. At this time, the controller 66 of the processor device 12 detects the amount of illumination light from the imaging signal acquired from the electronic endoscope 11 and determines whether or not the electronic endoscope 11 is performing close observation. Then, the controller 66 determines that the electronic endoscope 11 is performing close-up observation after the peak value P at which the illumination light amount switches from increase to decrease has passed.

The controller 66 that has determined that the close-up observation is performed applies a voltage to the first and second electrode members 44 and 45 of the liquid lens 40. As a result, the illumination optical systems 27a and 27b constituted by the liquid lens 40 can switch to a wider illumination angle than a narrow illumination angle during normal observation, and irradiate illumination light over a wide illumination range. Accordingly, the illumination optical system 27a, 27b illumination range S _L of, for overlapping the observation range S _O of the objective optical system 26 (the state shown in FIG. 6), to brighten an observation image taken in from the objective optical system 26, clearly An observation image can be acquired.

  As described above, the electronic endoscope 11 can switch the irradiation angle by a simple control of applying a voltage to the first and second electrode members 44 and 45 of the liquid lens 40, and the illumination optical system 27a, The light distribution characteristic of 27b can be varied. Furthermore, since the illumination range is switched by switching the irradiation angle, the light supplied from the light source 68 and entering the liquid lens 40 is not lost, and the illumination light can be efficiently irradiated.

  In the above embodiment, the illumination angle is varied by curving the boundary surface 54 of the liquid lens 40 to overlap the illumination range with the observation range, but the present invention is not limited to this. In the second embodiment of the present invention described below, the illumination range is overlapped with the observation range by tilting the boundary surface of the liquid lens and changing the direction of the optical axis.

  In the electronic endoscope of the second embodiment, as shown in FIG. 9, illumination optical systems 81a and 81b are provided at the distal end portion 80 of the insertion portion. The configuration other than the distal end portion 80 is the same as that of the electronic endoscope system 10 of the first embodiment. The illumination optical system 81a includes a liquid lens 82 and an optical fiber 31a, and the illumination optical system 81a includes a liquid lens 82 and an optical fiber 31b. In FIG. 9, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 10, the liquid lens 82 includes a case 83, and a conductive liquid 84 and an insulating liquid 85 that are sealed in the case 83 and do not mix with each other.

  As shown in FIG. 11, the case 83 includes a base 86, a cap 87, a seal member 88, and transparent covers 89 and 90 that are integrally provided. The base 86 has the same shape as the first electrode member 44 of the first embodiment, that is, a substantially cylindrical shape, and the inner peripheral surface 86a (see FIG. 10) gradually increases in inner diameter from the distal end side toward the proximal end side. Is formed in a tapered shape, and a cover holding portion 86c is formed on the base end side. A thin insulating film 91 is formed on the inner peripheral surface 86a and the tip end surface 86b (see FIG. 10) of the base 86. The base 86 is formed by integrating the first electrode member 92 and the insulating member 93 in half with respect to the circumferential direction. The first electrode member 92 is made of a conductive material, and the insulating member 93 is made of an insulating material.

  The cap 87 has the same shape as the second electrode member 45 of the first embodiment, and includes a cylindrical portion 94 that covers the outer periphery of the base 86 and a tip plate portion 95 that covers the tip side. In the portion 95, a cover holding portion 95a is formed on the tip side. The cap 87 is formed by integrating the second electrode member 96 and the insulating member 97 in half with respect to the circumferential direction. The second electrode member 96 is made of a conductive material, and the insulating member 97 is made of an insulating material.

  The cap 87 is attached to the distal end side of the base 86 through the seal member 88 so that the positions of the first electrode member 92 and the second electrode member 96 in the circumferential direction are aligned. The base 86 and the cap 87 are fixed with the seal member 88 interposed therebetween, and the transparent covers 89 and 90 are fixed to the cover holding portions 86c and 95a, and the front end and the base end are sealed to form the case 83. . In fixing the base 86, the cap 87, and the seal member 46, and fixing the cover holding portions 86c and 95a and the transparent covers 89 and 90, it is preferable to securely bond them by a method such as flowing an adhesive into the gap.

  The conductive liquid 84 and the insulating liquid 85 are sealed on the proximal end side and the distal end side in the case 83, respectively, and the insulating liquid 85 is in contact with the inside of the base 86 and the insulating film 91 and protrudes from the distal end face 86b. The amount of the conductive liquid 84 is set so as to contact the inner peripheral surface 87 a of the cap 87 and a part of the insulating film 91 of the base 86.

  The first and second electrode members 89 and 96 are arranged so as to be objective with respect to the circumferential direction of the liquid lens 82 when the illumination optical systems 81a and 81b, that is, the liquid lens 82 are incorporated in the distal end portion 80 of the endoscope insertion portion. It is arranged at a position close to the optical system 26. Therefore, in the illumination optical systems 81a and 81b, the first and second electrode members 92 and 96 are arranged at positions facing each other (see FIG. 9).

  The first and second electrode members 92 and 96 are connected to the processor device 12 via the wiring 98 in the same manner as the first and second electrode members 44 and 45 of the first embodiment. The controller 66 controls the application of voltage. When no voltage is applied to the first and second electrode members 92 and 96, the boundary surface 99 between the conductive liquid 84 and the insulating liquid 85 is substantially planar (the state shown by the solid line in FIG. 10). ). At this time, the optical axis directions of the illumination optical systems 81 a and 81 b are substantially parallel to the optical axis direction of the objective optical system 26.

  When a voltage is applied to the first and second electrode members 92 and 96, the conductive liquid 84 is drawn so as to approach one of the first electrode members 92. At this time, the insulating liquid 85 on the side where the first and second electrode members 92 and 96 are located is pushed out and gathers on the opposite side of the case 41 with respect to the circumferential direction of the liquid lens 82. As a result, the boundary surface 99 is curved and tilted to the side where the first and second electrode members 92 and 96 are located, thereby changing the direction of the optical axis of the illumination optical system (indicated by a two-dot chain line in FIG. 10). Status).

Since the first and second electrode members 92 and 96 are disposed in the vicinity of the objective optical system 26 with respect to the circumferential direction of the liquid lens 82, the first and second electrode members 92 and 96 are switched by applying a voltage to the liquid lens 82. the illumination optical system 81a, an optical axis L of 81b tilts the observation range _{S O} side of the objective optical system 26. Accordingly, the illumination optical system 81a, overlap the observation range S _O of the illumination range S _L and the objective optical system 81b, it is possible to brighten an observation image. As described above, the light distribution characteristics of the illumination optical systems 81a and 81b can be varied by a simple control of applying a voltage to the first and second electrode members 92 and 96 (state shown in FIG. 9). Furthermore, since the illumination range is switched by changing the optical axis directions of the illumination optical systems 81a and 81b, the illumination light can be efficiently irradiated without losing the light incident on the liquid lens 82. it can.

  In each of the above embodiments, the amount of illumination light is detected from the imaging signal acquired by the electronic endoscope, and whether or not the electronic endoscope is performing close observation is determined from the amount of illumination light. In response to this, it is configured to switch whether or not to apply a voltage to the liquid lenses 40 and 82, but the present invention is not limited to this, and the user operates the operation unit of the processor device or the operation unit of the electronic endoscope. Then, it may be switched whether to apply a voltage. Further, as a means for detecting the illumination light quantity, a photoelectric sensor different from the image sensor for acquiring the imaging signal may be provided at the distal end portion of the electronic endoscope so as to detect the illumination light quantity in the observation range.

  In each of the above embodiments, a xenon tube is used as the light source 68, but another white light source may be used, and a laser light source or an LED light source may be used. When a laser light source or an LED light source is used, it is a phosphor that emits fluorescence when excited with laser light or LED light of a predetermined wavelength, and a phosphor that forms white light composed of laser light or LED light and fluorescence. The phosphor may be disposed between the light guide emitting end and the liquid lenses 40 and 82 to emit white light.

  Furthermore, in each of the above embodiments, the illumination optical system receives light from the light source and irradiates the illumination light, so that heat from the light source is transmitted and the liquid temperature of the liquid lenses 40 and 82 may increase. Therefore, a cooling unit may be disposed in the vicinity of the liquid lens 40. As this cooling means, for example, an air / water channel for transmitting a fluid to the air / water nozzle 29 may be disposed in the vicinity of the liquid lenses 40 and 82. In this case, in order to transmit fluid such as water or air, the air / water supply channel having a relatively low temperature absorbs the heat generated by the liquid lenses 40 and 82 inside the insertion portion 16. Therefore, the liquid lenses 40 and 82 can be sufficiently cooled.

  Further, in each of the above embodiments, the configuration of the boundary surface is changed by applying a voltage to a pair of electrode members provided in a case that encloses the insulating liquid and the conductive liquid using the electrowetting phenomenon. However, the configuration of the liquid lens is not limited to this. For example, a liquid lens that changes the shape of the boundary surface by changing the pressure in the case that seals two types of liquids that do not mix with each other may be used. Good.

  Moreover, in the said 2nd Embodiment, it is set as the part which arrange | positions an electrode in the circumferential direction half with respect to electroconductive liquid and insulating liquid, However, this invention is not limited to this, The circumference | surroundings of electroconductive liquid and insulating liquid are used. It is only necessary that the electrode is disposed even at a part with respect to the direction. For example, the electrode may be formed so that 1/3 of the circumferential direction is an electrode member and the remaining 2/3 is disposed as an insulating member.

  In each of the above embodiments, an electronic endoscope that observes an image obtained by imaging the state of a subject using an imaging device has been described as an example. However, the present invention is not limited to this and is not limited to an optical endoscope. The present invention can also be applied to an endoscope that employs an image guide to observe the state of a subject.

DESCRIPTION OF SYMBOLS 10 Electronic endoscope system 11 Electronic endoscope 16 Insertion part 16a, 80 Tip part 26 Objective optical system (observation optical system)
27a, 27b, 81a, 81b Illumination optical system 30 Imaging unit 31a, 31b Optical fiber 40, 82 Liquid lens 42, 84 Conductive liquid 43, 85 Insulating liquid 44, 92 First electrode member 45, 96 Second electrode Member 54,99 Interface

Claims (8)

An insertion part to be inserted into the subject;
An observation optical system that is arranged at the distal end of the insertion portion and captures image light of the subject;
An endoscope comprising a liquid lens that deforms a boundary surface of a liquid to vary a light distribution characteristic of illumination light, and includes an illumination optical system that irradiates the illumination light into a subject.   The endoscope according to claim 1, wherein the liquid lens switches an irradiation angle of the illumination optical system to a wider angle when approaching the observation optical system than when performing normal observation.   The liquid lens is a liquid lens using an electrowetting phenomenon, and a substantially cylindrical case whose front end and base end are covered with a transparent cover, and a non-mixable conductive liquid and an insulation sealed in the case. A conductive liquid and a pair of electrodes that are arranged over the entire circumference of the base end and the distal end side of the conductive liquid and the insulating liquid and to which a voltage is applied, by applying a voltage to the electrode 3. The endoscope according to claim 2, wherein the irradiation angle is varied by drawing the conductive liquid to one of the electrodes and changing a curvature of a boundary surface between the conductive liquid and the insulating liquid. mirror.   The endoscope according to claim 1, wherein the liquid lens tilts the optical axis direction of the illumination optical system toward an observation range by the observation optical system when the observation optical system approaches.   The liquid lens is a liquid lens using an electrowetting phenomenon, and a substantially cylindrical case whose front end and base end are covered with a transparent cover, and a non-mixable conductive liquid and an insulation sealed in the case. A conductive liquid and a pair of electrodes that are arranged at a base end and a distal end side of the conductive liquid and the insulating liquid and a part of the circumferential direction, and to which a voltage is applied, and by applying a voltage to the electrode 5. The endoscope according to claim 4, wherein the conductive liquid is attracted to one of the electrodes and a boundary surface between the conductive liquid and the insulating liquid is inclined to change the optical axis direction.   The endoscope according to claim 3 or 5, wherein the pair of electrodes are provided integrally with the case.   The liquid lens includes a determination unit that determines whether or not the observation optical system has switched from normal observation to close-up observation, and when the determination unit determines that the observation optical system has switched from normal observation to close-up observation. A voltage is applied to the illumination optical system to switch the irradiation angle of the illumination optical system to a wide angle, or the optical axis direction is tilted toward the observation range by the observation optical system. The endoscope according to item.   A light amount detecting unit that detects an illumination light amount of an observation range in which image light is captured by the observation optical system, and the determination unit is configured to change the observation optical when the light amount detected by the light amount detection unit is switched from increase to decrease; 8. The endoscope according to claim 7, wherein it is determined that the system has switched from normal observation to approach observation.

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