ENDOSCOPE AND ENDOSCOPE SYSTEM

An endoscope includes an insertion unit, an operation unit, an emission end, a first light guide and a second light guide that guide illumination light emitted from a light source unit to the emission end, a lens member that suppresses a variation in a relative intensity of each color light of the illumination light, and a connection unit that optically connects the first light guide, the second light guide, and the lens member; and the lens member is disposed between the first light guide and the second light guide, and the connection unit and the lens member are provided in the operation unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C § 119(a) to Japanese Patent Application No. 2021-161645 filed on Sep. 30, 2021. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope and an endoscope system.

2. Description of the Related Art

Endoscopes are widely used in the medical field and the industrial field. An endoscope includes an insertion unit to be inserted into an object to be examined, and irradiates an object to be observed with illumination light from a distal end portion of the insertion unit. A light guide part for guiding illumination light, which is supplied from a light source device, to the distal end portion of the insertion unit is provided in the endoscope. The light guide part guides illumination light, and the object to be observed is illuminated with the illumination light, so that the inside of the object to be examined can be observed.

In a case where a light guide formed of one optical fiber bundle is used, ease of assembly is poor, and it is difficult to satisfy optical performance. Accordingly, it is known that a light guide part is formed of a plurality of light guides having different characteristics and of an optical member. In an endoscope disclosed in JP1994-296584A (JP-H06-296584A), a light guide part comprises a plurality of light guides. The light guide is formed of, for example, a fiber bundle in which quartz fibers or multi-component fibers are bundled. Since light transmittance and a light distribution width of the optical performance of a fiber bundle are in a trade-off relationship, it is difficult to manufacture a fiber bundle that satisfies both light transmittance and a light distribution width. Accordingly, in the endoscope disclosed in JP1994-296584A (JP-H06-296584A), a lens as an optical member is disposed between the plurality of light guides. In a case where this lens is used, a reduction in the amount of light and deterioration in the distribution of light are prevented, and light emitted from an end portion of a light source-side light guide is transmitted to an end portion of a distal end portion-side light guide.

However, there is an endoscope in which a bendable part is provided at the distal end of an insertion unit to allow a user to observe a portion to be observed at various angles or to easily insert the insertion unit. In the endoscope disclosed in JP1994-296584A (JP-H06-296584A), the end portions of the light guides and the lens are disposed in a bendable part.

SUMMARY OF THE INVENTION

However, since the end portions of the light guides and the lens are disposed in the bendable part in the endoscope disclosed in JP1994-296584A (JP-H06-296584A), there is a possibility that an optical axis is shifted. That is, in a case where the bendable part is bent, the central axes of the end portions of the light source-side light guide and the distal end portion-side light guide facing the lens do not coincide with the central axis of the lens for preventing a reduction in the amount of light and deterioration in the distribution of light. For this reason, there is a high probability that deterioration in performance, such as a reduction in the amount of light and deterioration in the distribution of light, will occur. Further, one light guide is lengthened in this case. In a case where the light guide is long, the ease of assembly of the endoscope deteriorates.

Further, a structure in which the end portions of the light guides and the lens are disposed in a connector used to connect the endoscope to the light source device is conceivable. However, since the light guides are disposed from the distal end portion of the endoscope to the inside of the connector in this case, the light guides are lengthened. For this reason, an ease of assembly deteriorates as in the endoscope disclosed in JP1994-296584A (JP-H06-296584A).

An object of the present invention is to provide an endoscope and an endoscope system which can prevent a reduction in the amount of illumination light and deterioration in the distribution of the illumination light and of which ease of assembly is improved.

An endoscope according to an aspect of the present invention is an endoscope that is connected to a light source device emitting illumination light in which a plurality of color lights are mixed by a plurality of light sources emitting color lights different from each other. The endoscope comprises an insertion unit, an operation unit, an illumination light-emission end, a light guide part that guides the illumination light, and a connection unit; and the optical member is disposed between the plurality of light guides, and the connection unit and the optical member are provided in the operation unit. The insertion unit is inserted into an object to be examined The operation unit is connected to the insertion unit. The illumination light-emission end is provided at a distal end portion of the insertion unit. The light guide part includes a plurality of light guides that guide the illumination light emitted from the light sources to the illumination light-emission end, and an optical member that suppresses a variation in a relative intensity of each color light of the illumination light, which is guided by the light guides and is emitted from the illumination light-emission end, with respect to a light distribution angle. The connection unit optically connects the light guides by holding the plurality of light guides and the optical member.

It is preferable that the insertion unit includes a protection sheath and a shaft member inserted into the protection sheath, the operation unit includes an operation unit body connected to a proximal end side of the shaft member, the connection unit is fixed to the protection sheath, and portions of the plurality of light guides held by the connection unit are rotationally moved in a direction around an axis of the insertion unit together with the protection sheath.

It is preferable that the insertion unit includes an outer pipe forming an outer peripheral wall, the protection sheath is inserted into the outer pipe, and the light guides are inserted between the outer pipe and the protection sheath. It is preferable that the operation unit includes a rotational moving operation member supported by the operation unit body to be rotationally movable and that the protection sheath and the light guides are rotationally moved in a same direction as the rotational moving operation member as the rotational moving operation member is rotationally moved.

It is preferable that the endoscope further comprises a signal cable that transmits and receives a signal, the signal cable is inserted into the shaft member, and the light guides are rotationally moved at positions outside the signal cable in a radial direction in a case where the light guides are rotationally moved together with the protection sheath.

It is preferable that the endoscope further comprises a holding member that holds the light guides, the optical member, and the connection unit and that is fixed to the protection sheath; and it is preferable that the holding member is formed in a tubular shape and that the light guides, the optical member, and the connection unit are held on an outer peripheral surface side of the holding member. It is preferable that the connection unit and the holding member are disposed in the operation unit body.

It is preferable that the endoscope further comprises a housing provided in the operation unit and connected to the protection sheath and a connecting unit magnetically connecting the shaft member to the operation unit body, the protection sheath and the housing form an air-tight space, the housing includes a partition wall closing a proximal end side thereof, and the connecting unit magnetically connects the shaft member to the operation unit body with the partition wall interposed therebetween.

It is preferable that the optical member is a lens member that, in a case where a relative intensity of one color light among the plurality of color lights emitted from the light sources is used as a reference, makes relative intensities of the other color lights have a difference of ±5% or less from the relative intensity of the color light used as the reference.

An endoscope system according to another aspect of the present invention comprises the endoscope, and a light source device that emits illumination light in which a plurality of color lights are mixed by a plurality of light sources emitting color lights different from each other.

According to the present invention, it is possible to prevent a reduction in the amount of illumination light and deterioration in the distribution of the illumination light and to improve ease of assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Schematic Configuration of Endoscope System

As shown inFIG.1, an endoscope system10includes an endoscope12, a light source device13, a processor device14, a monitor15, and a user interface16. The endoscope12is, for example, a rigid endoscope, such as a laparoscope.

As shown inFIG.2, the endoscope12comprises an elongated rigid insertion unit17that is to be inserted into an object to be examined, an L-shaped operation unit18that is connected to a proximal end portion of the insertion unit17, a soft universal cable19that is connected to the insertion unit17via the operation unit18, a switch-disposition member21that is provided in a middle portion of the universal cable19, and an endoscope-side connector22.

The endoscope12is an oblique-viewing endoscope of which a visual field direction (see an optical axis OA ofFIG.5) of an image pickup unit25(seeFIGS.3and5) to be described later is inclined with respect to an insertion axis Ax of the insertion unit17. The image pickup unit25comprises an image pickup sensor26to be described later (seeFIGS.3and5).

As shown inFIG.3, a first light guide27A and a first signal cable28A are inserted into the insertion unit17. The first light guide27A forms a light guide27, which guides illumination light emitted from the light source device13, together with a lens member27C and a second light guide27B. The first signal cable28A forms a signal cable28together with an air-tight connector82(seeFIG.8) and a second signal cable28B to be described later. The signal cable28includes a control line that transmits control signals used to control the image pickup sensor26, a signal line that transmits image signals output from the image pickup sensor26in a case where the image of an object to be observed irradiated with illumination light is picked up, a power line that supplies power to each part, such as the image pickup sensor26, and the like. Since the configuration of the light guide27and the signal cable28will be described in detail later, the description thereof is omitted here.

The endoscope-side connector22is provided at a proximal end portion of the universal cable19. The endoscope12is attachably and detachably connected to a light source device-side connector36of the light source device13via the endoscope-side connector22. The universal cable19is a cable in which the second light guide27B and the second signal cable28B are integrated with each other.

The endoscope system10according to this embodiment has a configuration in which power, optical signals, and the like are transmitted between the endoscope12and the light source device13via the endoscope-side connector22and the light source device-side connector36in a contactless manner.

Further, for example, an image selector switch, which is used to switch an image displayed on the monitor15to a normal picked-up image and to a special light image (for example, a white light (WL) image, a blue laser imaging (BLI) image, a linked color imaging (LCI) image, or a low-oxygen imaging image), can be applied as an operation switch21A disposed on the above-mentioned switch-disposition member21. Furthermore, the operation switch is not limited thereto, and an image stop switch, an image pickup switch, a zoom switch comprising a telephoto button and a wide button, a washing switch for a distal end portion of the insertion unit, a light amount-adjustment switch, a sensitivity-adjustment switch, or the like can also be applied.

The light source device13supplies illumination light to the second light guide27B (seeFIG.3). Accordingly, illumination light is emitted from an illumination light-emission end (hereinafter, simply referred to as an emission end)29of a distal end portion of the light guide27.

Schematic Configuration of Processor Device

The processor device14controls the amount and emission time of illumination light that is emitted from the light source device13, the operation of the image pickup sensor26, and the like, and generates an endoscopic image using image signals that are obtained from the image pickup of the object to be observed irradiated with illumination light. Further, the processor device14is electrically connected to the monitor15and to the user interface16. The monitor15displays the endoscopic image generated by the processor device14, information about the endoscopic image, and the like. The user interface16receives an input operation, such as function settings.

Schematic Configuration of Light Source Device

As shown inFIG.3, the light source device13comprises a light source unit31, a light source controller32, a wireless communication unit33, a wireless power supply unit34, and a signal transmission unit35. The light source unit31emits illumination light that is used to illuminate the object to be observed. The light source controller32controls the light source unit31. The signal transmission unit35transmits control signals, image signals, and the like between the light source device13and the processor device14.

The light source unit31includes semiconductor light sources, such as a plurality of color light emitting diodes (LEDs). The light source controller32adjusts the turning on or off of the LEDs or the drive currents or drive voltages of the LEDs to control the amounts of illumination light to be emitted. The semiconductor light sources of the light source unit31are not limited to LEDs and may be laser diodes (LDs) or the like.

The light source unit31includes four color LEDs, that is, a violet light emitting diode (V-LED)31a, a blue light emitting diode (B-LED)31b, a green light emitting diode (G-LED)31c, and a red light emitting diode (R-LED)31d.

The LEDs31ato31demit color lights different from each other. For example, the V-LED31aemits a violet light V having a wavelength range of 380 nm to 420 nm. The B-LED31bemits a blue light B having a wavelength range of 420 nm to 500 nm. The G-LED31cemits a green light G having a wavelength range of 480 nm to 600 nm. The R-LED31demits a red light R having a wavelength range of 600 nm to 650 nm. Lights emitted from the LEDs31ato31dmay have the same central wavelength and the same peak wavelength, and may have different central wavelengths and different peak wavelengths.

The light source controller32independently controls the turning on or off of each of the LEDs31ato31d, the amount of light emitted at the times of turning on thereof, and the like to adjust the emission time, emission period, amount, and spectrum of illumination light. The control of the turning on or off of each of the LEDs, which is performed by the light source controller32, varies depending on each observation mode. Reference brightness can be set by the user interface16or the like.

In the case of a normal mode, the light source controller32turns on all the V-LED31a, the B-LED31b, the G-LED31c, and the R-LED31d. Accordingly, in the normal mode, polychromatic light for a normal mode, which includes a violet light, a blue light, a green light, and a red light, is emitted from the light source device13as normal light. Since a violet light, a blue light, a green light, and a red light are mixed in the normal light and the normal light has intensity equal to or higher than certain intensity from a blue light wavelength range to a red light wavelength range, the normal light is a substantially white light. A white light includes not only broadband light that includes all the wavelength ranges of a blue light component, a green light component, and a red light component like a white light emitted from a xenon lamp, but also illumination light in which lights having wavelength ranges of at least three color light components, such as a blue light component, a green light component, and a red light component are mixed.

In the case of a special mode, the light source controller32turns on all the V-LED31a, the B-LED31b, the G-LED31c, and the R-LED31dbut sets a light amount ratio between a violet light, a blue light, a green light, and a red light in this case so that a ratio of a violet light is increased. Accordingly, a special light is a bluish light. The case of the normal mode in which a white light is emitted as illumination light will be mainly described below.

Further, the light source device13is electrically connected to the processor device14, and the endoscope-side connector22of the endoscope12is connected to the processor device14via the light source device13. The transmission and reception of image signals and the like between the light source device13and the endoscope-side connector22are via wireless communication. For this reason, the light source device13outputs image signals and the like, which are transmitted to and received from the endoscope-side connector22wirelessly, to the signal transmission unit35, and the signal transmission unit35transmits the image signals and the like to the processor device14. Furthermore, the light source device13supplies power, which is used to drive the image pickup sensor26and the like, to the endoscope-side connector22but also supplies this power wirelessly.

As shown inFIG.4, the light source device-side connector36is provided with the wireless communication unit33, the wireless power supply unit34, locking portions36A and36B, and a connection hole36C. In a case where the endoscope-side connector22is connected, the locking portions36A and36B lock the endoscope-side connector22to maintain the connection of the endoscope-side connector22. The connection hole36C is a through-hole, and a light guide rod22A (seeFIG.3) of the endoscope-side connector22is inserted into the connection hole36C.

In a case where the endoscope-side connector22is to be connected to the light source device-side connector36, the light guide rod22A is inserted into the connection hole36C of the light source device-side connector36, so that an incident end37(seeFIG.3) of the second light guide27B faces the light source unit31of the light source device13. Accordingly, illumination light emitted from the light source unit31is transmitted via the light guide27and is applied to a front side of the insertion unit17from the emission end29.

The wireless communication unit33includes an image signal receiving part33A (seeFIG.3). The image signal receiving part33A receives image signals from an image signal transmission part38A of the endoscope-side connector22. The wireless power supply unit34is, for example, a coil (so-called primary coil), and supplies power to a wireless power receiving unit39with a contactless power transmission method, such as an electromagnetic induction method or a magnetic resonance method.

In a case where the endoscope-side connector22of the endoscope12is connected to the light source device-side connector36of the light source device13, illumination light emitted from the light source unit31is incident on the second light guide27B of the endoscope12by, for example, a light guide member (not shown), such as a prism or a light guide rod.

The light guide27is built in the endoscope12including the universal cable19and the endoscope-side connector22, and guides illumination light to a distal end portion17A of the endoscope12. The distal end portion17A is provided with the emission end29. The emission end29is disposed around the image pickup unit25, and is a distal end of the first light guide27A. In this embodiment, the image pickup unit25and the emission end29are exposed from a distal end surface of the distal end portion17A. Illumination light emitted from the light source unit31is guided from the light source unit31by the light guide27and is applied to the object to be observed from the emission end29.

The endoscope-side connector22is provided with a wireless communication unit38and a wireless power receiving unit39. The wireless communication unit38includes an image signal transmission part38A (seeFIG.3). The image signal transmission part38A transmits image signals, which are obtained from the image pickup of the object to be observed by the image pickup sensor26, to the image signal receiving part33A of the light source device13wirelessly. Wireless communication performed by the wireless communication unit38is optical communication, and it is preferable that this wireless communication is, for example, near-infrared communication using near-infrared light (light having a wavelength of about 0.7 μm to 2.5 μm).

In a case where the endoscope-side connector22and the light source device-side connector36are connected to each other, the wireless communication unit38can transmit and receive optical signals to and from the wireless communication unit33of the light source device13. That is, image signals of the image signal transmission part38A are optically transmitted to the image signal receiving part33A of the light source device13in a contactless manner.

The image signals optically transmitted to the image signal receiving part33A are transmitted to the processor device14by the signal transmission unit35. The image signals, which are transmitted to the processor device14from the endoscope12via the light source device13, are displayed on the monitor15as an endoscopic image subjected to image processing. The functions of the wireless communication units33and38are not limited to the above-mentioned functions and may be to transmit and receive control signals that are used to control, for example, the image pickup sensor26and the like of the endoscope12.

The wireless power receiving unit39is, for example, a coil (so-called secondary coil) and receives power that is supplied from the wireless power supply unit34provided in the light source device13with a contactless power transmission method. Since an endoscope that uses a primary coil and a secondary coil to supply power is publicly known in JP2016-67534A (corresponding to US 2016/089001A1), the detailed description thereof will be omitted here. The wireless power receiving unit39supplies power to each part of the endoscope12, such as the image pickup sensor26.

Configuration of Endoscope

As shown inFIG.5, the insertion unit17comprises a substantially cylindrical outer pipe40(also referred to as a mantle pipe) parallel to the insertion axis Ax, a protection sheath42, and an inner sheath44. The outer pipe40forms an outer peripheral wall of the insertion unit17. An opening of a distal end portion of the outer pipe40is inclined from a posture perpendicular to the insertion axis Ax. Further, as described in detail later, a proximal end portion of the outer pipe40is connected to the operation unit18(seeFIGS.2and6).

The protection sheath42is inserted into and disposed in the outer pipe40. A distal end optical system50of the image pickup unit25is provided in a distal end portion of the protection sheath42. Further, as described in detail later, a proximal end portion of the protection sheath42is connected to a housing74(seeFIG.8) provided in the operation unit18. Furthermore, an insertion passage41for the light guide27is formed between an inner peripheral surface of the outer pipe40and an outer peripheral surface of the protection sheath

The inner sheath44corresponds to a shaft member of the present invention, and is inserted into and disposed in the protection sheath42. The first signal cable28A is inserted into the inner sheath44. A proximal end optical system60and the image pickup sensor26of the image pickup unit25are provided in a distal end portion of the inner sheath44. Further, as described in detail later, a proximal end portion of the inner sheath44is connected to a first connection member90(seeFIG.8) provided in the operation unit18.

The image pickup unit25comprises the distal end optical system50, the proximal end optical system60, and the image pickup sensor26. Reference character OA shown inFIG.5denotes the optical axis of the optical system of the image pickup unit25.

The distal end optical system50is provided in the distal end portion of the protection sheath42. The distal end optical system50is an oblique-viewing optical system that refracts light, which is incident in a direction inclined with respect to the insertion axis Ax, in a direction parallel to the insertion axis Ax and guides the light to the proximal end optical system60. The distal end optical system50includes a distal end portion body52and a distal end lens barrel54that is provided in the distal end portion body52.

The distal end portion body52forms the distal end portion17A of the insertion unit17(protection sheath42) and is a cap (cover) that covers the distal end lens barrel54. The distal end portion body52is formed substantially in the shape of a cylinder parallel to the insertion axis Ax. Further, a cover glass56, which is in an inclined posture corresponding to an inclination angle of an objective lens58aprovided in the distal end lens barrel54, is provided at a distal end-side opening portion of the distal end portion body52.

Furthermore, the distal end portion body52is fixed to the inner peripheral surface of the outer pipe40. Accordingly, the outer pipe40, the distal end optical system50, and the protection sheath42are integrally moved rotationally in a direction around the insertion axis Ax (hereinafter, simply abbreviated as a direction around the axis).

The distal end lens barrel54houses the objective lens58a, a prism58b, and a lens58c. The objective lens58ais inclined from a posture perpendicular to the insertion axis Ax and faces the cover glass56. The objective lens58aemits light, which is incident through the cover glass56, toward the prism58b. The prism58bcorresponds to a second refractive optical element of the present invention, and refracts light incident from the objective lens58a, that is, light incident in a direction inclined with respect to the insertion axis Ax in a direction parallel to the insertion axis Ax, and then emits the light toward the lens58c. The lens58cis in a posture perpendicular to the insertion axis Ax, and emits light incident from the prism58btoward lenses66that are provided in a proximal end lens barrel62of the proximal end optical system60to be described later.

The configuration of an optical system provided in the distal end lens barrel54is not particularly limited as long as light incident in a direction inclined with respect to the insertion axis Ax can be guided into the proximal end lens barrel62.

A tubular portion55, which extends toward a proximal end of the distal end lens barrel54, is formed at the distal end lens barrel54. The tubular portion55is externally fitted to be rotatable relative to a distal end portion of the proximal end lens barrel62to be described later in the direction around the axis. Accordingly, the proximal end lens barrel62is fitted to be rotatable relative to the distal end lens barrel54in the direction around the axis. The tubular portion55is formed integrally with the distal end lens barrel54in this embodiment, but may be formed separately from the distal end lens barrel54.

The proximal end optical system60is provided in the distal end portion of the inner sheath44, and guides light, which is incident from the distal end lens barrel54, to the image pickup sensor26. The proximal end optical system60includes the proximal end lens barrel62, a holder64, and a prism65.

The proximal end lens barrel62is connected (fixed) to the distal end portion of the inner sheath44via the holder64. A proximal end portion of the proximal end lens barrel62may be directly connected to the distal end portion of the inner sheath44, and the holder64may be connected to the proximal end portion of the proximal end lens barrel62in the inner sheath44.

Further, the distal end portion of the proximal end lens barrel62is fitted to be rotatable relative to a proximal end-side opening portion of the tubular portion55in the direction around the axis as described above. Accordingly, one of the distal end lens barrel54and the proximal end lens barrel62is rotatable relative to the other thereof in the direction around the axis. A proximal end portion of the distal end lens barrel54may be fitted into a distal end-side opening portion of the proximal end lens barrel62to be rotatable relative to the distal end-side opening portion of the proximal end lens barrel62in the direction around the axis.

A plurality of lenses66having an optical axis OA parallel to the insertion axis Ax are provided in the proximal end lens barrel62. The lenses66emit light, which is incident from the distal end lens barrel54, toward the prism65.

The holder64is formed substantially in the shape of a cylinder parallel to the insertion axis Ax, and is fixed to the distal end portion of the inner sheath44. Further, the holder64is connected and fixed (externally fitted and fixed) to the proximal end portion of the proximal end lens barrel62. Accordingly, since the inner sheath44and the proximal end lens barrel62are connected to each other by the holder64, the inner sheath44, the proximal end lens barrel62, and the holder64are integrated.

The prism65is held at a proximal end-side opening portion of the holder64, and the image pickup sensor26to be described later is held via the prism65. For this reason, the image pickup sensor26is integrated with the inner sheath44and the proximal end lens barrel62via the holder64and the prism65.

The prism65corresponds to a first refractive optical element of the present invention, and is held at the proximal end-side opening portion of the holder64as described above. The prism65refracts light, which is incident through the proximal end lens barrel62, by an angle of 90°. A mirror may be used instead of the prism65.

The image pickup sensor26picks up the image of light that passes through the distal end lens barrel54and the proximal end lens barrel62and that is reflected by the prism65. The image pickup sensor26is provided integrally with a circuit board67.

The image pickup sensor26is, for example, a color sensor including primary color filters, and comprises three types of pixels, that is, B pixels (blue pixels) including blue color filters, G pixels (green pixels) including green color filters, and R pixels (red pixels) including red color filters. The blue color filter mainly transmits violet to blue light. The green color filter mainly transmits green light. The red color filter mainly transmits red light. In a case where the image of the object to be observed is picked up using the primary color image pickup sensor26as described above, a maximum of three types of images, that is, a B image (blue image) obtained from B pixels, a G image (green image) obtained from G pixels, and an R image (red image) obtained from R pixels, can be simultaneously obtained.

A charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor can be applied as the image pickup sensor26. Further, the image pickup sensor26of this embodiment is a primary color sensor, but a complementary color sensor can also be used. A complementary color sensor includes, for example, cyan pixels provided with cyan color filters, magenta pixels provided with magenta color filters, yellow pixels provided with yellow color filters, and green pixels provided with green color filters. In a case where a complementary color sensor is used, images obtained from the respective color pixels described above can be converted into B images, G images, and R images by complementary color-primary color conversion. Further, a monochrome sensor not provided with color filters may be used as the image pickup sensor26instead of the color sensor. In this case, the images having the respective colors can be obtained from the sequential image pickup of the object to be observed using illumination light having the respective colors, such as B, G, and R.

The image pickup sensor26is mounted on the holder64via the prism65in this embodiment, but the image pickup sensor26may be directly mounted on the proximal end-side opening portion of the holder64. In this case, it is preferable that the image pickup sensor26is held by the holder64in a posture perpendicular to the insertion axis Ax (optical axis OA) and has a light-receiving surface orthogonal to the optical axis OA.

The circuit board67controls the drive of the image pickup sensor26. Further, a distal end portion of the first signal cable28A is connected to the circuit board67via a connector68. Furthermore, the circuit board67outputs image signals, which are output from the image pickup sensor26, to the first signal cable28A via the connector68.

Configuration of Operation Unit

As shown inFIGS.6and7, the operation unit18comprises a rotational moving operation member70, a connecting member71, and an operation unit body72. The operation unit18is formed of, for example, a resin component and has high stiffness. The rotational moving operation member70is an operation ring that is formed substantially in the shape of a cylinder parallel to the insertion axis Ax, and receives a rotational moving operation that is performed in the direction around the axis by a user.

The proximal end portion of the above-mentioned outer pipe40is connected to a distal end portion of the rotational moving operation member70. Accordingly, in a case where the rotational moving operation member70is operated to rotationally move in the direction around the axis, the protection sheath42and the distal end optical system50(the distal end portion body52and the distal end lens barrel54) are rotationally moved in the same direction via the outer pipe40. Therefore, the visual field direction (observation direction, see the optical axis OA shown inFIG.5) of the endoscope12can be rotationally moved in the direction around the insertion axis Ax (a circumferential direction of the insertion unit17and the rotational moving operation member70).

The connecting member71is formed in a substantially cylindrical shape. A seal member73is externally fitted to an outer peripheral surface of a distal end portion of the connecting member71. Further, the connecting member71is fitted to an inner peripheral surface of a proximal end portion of the rotational moving operation member70via the seal member73to be rotationally movable. The seal member73is an annular shape and, for example, OMNISEAL, an O-ring, or the like is used as the seal member73.

The operation unit body72is formed in the shape of a pipe bent in an L shape, and has an outer shape that allows a human user to grip the operation unit body72by hand. The connecting member71is fixed to a distal end portion of the operation unit body72. Accordingly, the operation unit body72supports the rotational moving operation member70via the connecting member71so that the rotational moving operation member70is rotationally movable. That is, in a case where a rotational movement force for rotationally moving the rotational moving operation member70in the direction around the axis is applied, this rotational movement force is not transmitted to the operation unit body72.

The rotational moving operation member70is rotationally movable in a predetermined angle range in the direction around the axis, and can be rotationally moved in a range of, for example, 0° to 170° clockwise and counterclockwise, respectively.

As shown inFIG.8, the proximal end portions of the protection sheath42and the inner sheath44in addition to the above-mentioned outer pipe40are inserted into a distal end-side opening portion of the rotational moving operation member70. In addition, a housing74, a connection unit110, and a holding member111(seeFIGS.9and10) are provided in the operation unit18. As described in detail later, the connection unit110and the holding member111hold the first light guide27A, the second light guide27B, and the lens member27C.

Further, a fixing member76is inserted into the operation unit body72. The fixing member76is formed substantially in the shape of a cylinder including a through-hole76A parallel to the insertion axis Ax. The second light guide27B and the second signal cable28B are inserted into the through-hole76A. A proximal end portion of the fixing member76is fixed to the operation unit body72, so that the operation unit body72and the fixing member76are integrated with each other. As described in detail later, the fixing member76is connected to a magnet coupling102via a second connection member100and a second bearing receiving member96.

The housing74is formed substantially in the shape of a pipe parallel to the insertion axis Ax to have a diameter smaller than inner diameters of the rotational moving operation member70, the connecting member71, and the operation unit body72, and is housed in the operation unit18. The housing74is supported in an internal space of the operation unit18by the protection sheath42, the fixing member76, and the like. A distal end side of the housing74is connected to the proximal end portion of the protection sheath42. Accordingly, the housing74and the protection sheath42are integrally moved rotationally in the direction around the axis. As a result, in a case where a rotational movement force for rotationally moving the rotational moving operation member70in the direction around the axis is applied, this rotational movement force is transmitted to the outer pipe40, the distal end optical system50, the protection sheath42, and the housing74. Accordingly, the outer pipe40, the distal end optical system50, the protection sheath42, and the housing74are rotationally moved in the same direction as the rotational moving operation member70.

The proximal end portion of the inner sheath44and a proximal end portion of the first signal cable28A are disposed in the housing74. Further, a partition wall74aperpendicular to the insertion axis Ax is provided in the housing74, for example, in a proximal end-side opening portion of the housing74. The partition wall74acloses the proximal end-side opening portion of the housing74.

A tubular portion74bparallel to the insertion axis Ax is provided on a proximal end side of the housing74. Further, the tubular portion74bmay be formed integrally with the housing74. As described in detail later, a distal end portion of the second signal cable28B is disposed in the tubular portion74bin addition to a part of a connecting unit84.

As shown inFIG.9, a sealed space80(air-tight space) is formed in the protection sheath42and the housing74, and the inner sheath44, the image pickup sensor26, the first signal cable28A, and the like are disposed in this sealed space80.FIG.9is a cross-sectional view of a portion near the protection sheath42and the housing74, and the rotational moving operation member70, the connecting member71, the operation unit body72, and the like are omitted.

A distal end side of the sealed space80is defined by the distal end optical system50. Further, a proximal end side of the sealed space80is defined by the partition wall74a. Accordingly, the moisture-proof property of the image pickup unit25is improved, so that fogging is prevented. Furthermore, since the seal member73is interposed between the rotational operation member70and the housing74as described above, the airtightness of the sealed space80is further improved.

As shown inFIGS.8and9, the partition wall74aalready described, the air-tight connector82, and the connecting unit84are provided in the housing74and the tubular portion74b. The air-tight connector82is provided to pass through the inside and the outside of the sealed space80and to be rotatable relative to the partition wall74ain the direction around the axis. The air-tight connector82electrically connects the first signal cable28A provided in the housing74(in the sealed space80) to the second signal cable28B provided in the tubular portion74b(outside the sealed space80).

The connecting unit84is provided in the housing74and the tubular portion74bto be rotatable relative to the housing74and the tubular portion74bin the direction around the axis. The first signal cable28A and the second signal cable28B are inserted into the connecting unit84. The connecting unit84magnetically connects the proximal end portion of the inner sheath44provided in the housing74(in the sealed space80) to the fixing member76provided outside the sealed space80with the partition wall74ainterposed therebetween.

The connecting unit84comprises a first connection member90, a first bearing receiving member92, a first bearing94, a second bearing receiving member96, a second bearing98, a second connection member100, and a magnet coupling102.

The first connection member90and the first bearing receiving member92are provided in the housing74(in the sealed space80), and are formed substantially in the shape of a pipe parallel to the insertion axis Ax. Further, the first signal cable28A is inserted into the first connection member90and the first bearing receiving member92.

The first connection member90connects the proximal end portion of the inner sheath44to the first bearing receiving member92in the housing74(in the sealed space80). Accordingly, the first bearing receiving member92is connected to the proximal end side of the inner sheath44via the first connection member90.

A distal end side of the first bearing receiving member92is connected to the first connection member90as described above. Further, the first bearing94, which is to be inscribed in the housing74, is fixed to an outer peripheral surface of the first bearing receiving member92. Accordingly, the first bearing receiving member92and first magnets103are held in the housing74to be rotatable relative to the housing74in the direction around the axis. Publicly known various radial bearings, such as a ball bearing and a roller bearing, are used as the first bearing94.

The second bearing receiving member96is provided in the tubular portion74b(outside the sealed space80), and the second connection member100is provided between the second bearing receiving member96and the fixing member76. The second bearing receiving member96and the second connection member100are formed substantially in the shape of a pipe parallel to the insertion axis Ax, and the second signal cable28B is inserted into each of the second bearing receiving member96and the second connection member100.

A proximal end portion of the second bearing receiving member96is connected to the second connection member100. Further, a second bearing98, which is to be inscribed in the tubular portion74b, is fixed to an outer peripheral surface of the second bearing receiving member96. Accordingly, the second bearing receiving member96and second magnets104are held in the tubular portion74bto be rotatable relative to the tubular portion74bin the direction around the axis. Publicly known various radial bearings are also used as the second bearing98as in the case of the first bearing94.

The second connection member100is integrally provided with a connection piece100A that is parallel to the insertion axis Ax and that protrudes toward the fixing member76. The connection piece100A is fixed to the fixing member76by, for example, screwing or the like. Accordingly, the fixing member76and the second bearing receiving member96are connected to each other via the second connection member100. Since the second connection member100and the fixing member76are connected to each other via the connection piece100A as described above, the second signal cable28B is exposed from a gap between the second connection member100and the fixing member76(seeFIG.10).

The magnet coupling102includes a plurality of first magnets103provided in the housing74(in the sealed space80) and a plurality of second magnets104provided in the tubular portion74b(outside the sealed space80) with the partition wall74ainterposed therebetween. The magnet coupling102is a magnetic connecting member that magnetically connects the first bearing receiving member92to the second bearing receiving member96.

The first magnets103and the second magnets104are arranged at positions facing each other with the partition wall74ainterposed therebetween, and are arranged in a circle around the insertion axis Ax. Accordingly, the first magnets103and the second magnets104are magnetically connected to each other in a direction parallel to the insertion axis Ax (axial direction) with the partition wall74ainterposed therebetween. As a result, the inner sheath44and the operation unit body72are magnetically connected to each other via the magnet coupling102.

Since the inner sheath44and the operation unit body72are magnetically connected to each other via the magnet coupling102, torque (stop torque, rotational torque) can be transmitted to the inner sheath44from the operation unit body72. Accordingly, in a case where a user rotationally moves the rotational operation member70, the rotational movement of the inner sheath44(the proximal end optical system60and the image pickup sensor26) and of the protection sheath42in the direction around the axis is prevented, that is, the posture of the inner sheath44in the direction around the axis is maintained by the magnet coupling102.

Configuration of Light Guide and Connection Unit

The light guide27includes the first light guide27A, the second light guide27B, and the lens member27C. Each of the first light guide27A and the second light guide27B is a fiber bundle in which optical fibers are bundled. The light guide27corresponds to a light guide part of the claims, and the lens member27C corresponds to an optical member of the claims. The optical fibers forming the first light guide27A and the second light guide27B are, for example, quartz fibers or multi-component fibers.

In this embodiment, a fiber bundle having a large numerical aperture (NA) is used as the first light guide27A, and a fiber bundle having high light transmittance is used as the second light guide27B. The fiber bundle having a large numerical aperture and the fiber bundle having high light transmittance, which are different types of fiber bundles, are used as described above, and the fiber bundle having high light transmittance (second light guide27B) is made long so that an end portion of the fiber bundle is disposed at a position as close as possible to a distal end of the endoscope12. Accordingly, the light guide27can suppress the loss of the amount of illumination light emitted from the light source unit31, and can widen light distribution at the emission end29of the first light guide27A. That is, the light guide27can obtain good optical performance in which the amount of light and light distribution are well-balanced.

In this embodiment, the first light guide27A, a part of the second light guide27B, and the lens member27C are disposed in the operation unit18, and, more specifically, are disposed in the operation unit body72.

As shown inFIGS.10and11, the first light guide27A, the second light guide27B, and the lens member27C are held by the connection unit110and are optically connected to each other. In addition, the first light guide27A, the second light guide27B, the lens member27C, and the connection unit110are held by the holding member111and are fixed to the housing74.

The connection unit110comprises a first ferrule112, a second ferrule113, and a lens holder114. The first ferrule112is formed in a cylindrical shape, and is adhered and fixed to a proximal end portion of the first light guide27A by, for example, an adhesive or the like. The second ferrule113is formed in a cylindrical shape, and is adhered and fixed to a distal end portion of the second light guide27B by, for example, an adhesive or the like.

The lens holder114is formed in a cylindrical shape, and has an inner peripheral surface corresponding to an outer peripheral surface of the lens member27C. The lens member27C is held on the inner peripheral surface of the lens holder114. The lens holder114is formed to have a dimension larger than the dimension of the lens member27C in the axial direction. The first ferrule112is inserted up to a position close to the lens member27C from a distal end side of the lens holder114together with the first light guide27A, and is fitted to the inner peripheral surface of the lens holder114.

The second ferrule113is inserted up to a position close to the lens member27C from a proximal end side of the lens holder114together with the second light guide27B, and is fitted to the inner peripheral surface of the lens holder114. As described above, the first light guide27A is held on the distal end side of the lens holder114together with the first ferrule112, and the second light guide27B is held on the proximal end side of the lens holder114together with the second ferrule113. Accordingly, the first light guide27A and the second light guide27B are optically connected to each other, and the lens member27C is disposed between the first light guide27A and the second light guide27B.

Configuration of Holding Member

As shown inFIG.12, the holding member111is formed in a tubular shape. Specifically, the holding member111includes a cylindrical portion111A that is parallel to the insertion axis Ax and a pair of protruding portions111B and111C that protrudes from an outer peripheral surface of the cylindrical portion111A. The cylindrical portion111A is externally fitted to an outer peripheral surface of the housing74and is fixed to the housing74by, for example, screwing. As described above, the housing74is connected to the protection sheath42. Accordingly, the holding member111is fixed to the protection sheath42via the housing74.

The protruding portions111B and111C are parallel to each other and are formed in a rectangular shape. The connection unit110is interposed between the protruding portions111B and111C, and is fixed to the holding member111by, for example, screwing. Accordingly, the first light guide27A, the second light guide27B, the lens member27C, and the connection unit110are held on an outer peripheral surface side of the holding member111. That is, the first light guide27A, the second light guide27B, the lens member27C, and the connection unit110are fixed to the protection sheath42via the holding member111and the housing74.

Since the protection sheath42is rotationally moved in the direction around the insertion axis Ax as described above, the connection unit110fixed to the protection sheath42and the first light guide27A, a part of the second light guide27B, and the lens member27C held by the connection unit110are also rotationally moved in the direction around the axis together with the protection sheath42via the holding member111and the housing74.

Further, since the protection sheath42is rotationally moved in the same direction as the rotational moving operation member70by the rotational movement force of the rotational moving operation member70as described above, the first light guide27A, a part of the second light guide27B, and the lens member27C are also rotationally moved in the same direction as the rotational moving operation member70together with the protection sheath42.

As described above, the first light guide27A and the second light guide27B are fixed to the protection sheath42via the holding member111and the housing74. Meanwhile, the signal cable28is inserted into the inner sheath44, and the inner sheath44is inserted into the protection sheath42. Accordingly, in a case where the first light guide27A and the second light guide27B are rotationally moved together with the protection sheath42, the first light guide27A and the second light guide27B are rotationally moved at positions outside the signal cable28in a radial direction.

FIG.13Ashows a case where the protection sheath42and the housing74are rotationally moved clockwise, andFIG.13Bshows a case where the protection sheath42and the housing74are rotationally moved counterclockwise. In either case, the first light guide27A and the second light guide27B are rotationally moved at positions outside the signal cable28in the radial direction in a case where the first light guide27A and the second light guide27B are rotationally moved together with the protection sheath42.

As described above, the second signal cable28B is exposed from a gap between the second connection member100and the fixing member76(see alsoFIG.10). Further, the second light guide27B and the second signal cable28B are inserted into the through-hole76A of the fixing member76together. In a case where the positions of the second light guide27B and the second signal cable28B are close to each other, there is a possibility that the second light guide27B and the second signal cable28B will be entangled with each other. However, in the present invention, the first light guide27A and the second light guide27B are rotationally moved at positions outside the signal cable28in the radial direction (the states shown inFIGS.13A and13B) in a case where the first light guide27A and the second light guide27B are rotationally moved together with the protection sheath42. Accordingly, the second light guide27B and the second signal cable28B are not entangled with each other, and the disconnection thereof can be prevented.

Configuration of Lens Member

As shown inFIG.11, the lens member27C is a plano-convex lens of which an incident side is convex and an emission side is planar. The lens member27C may be a biconvex lens, a meniscus lens, or the like without being limited thereto. It is preferable that an antireflection film called an anti-reflective (AR) coating is formed on each lens surface of the lens member27C. Accordingly, a reduction in the amount of illumination light in the light guide27can be further prevented.

In the light guide27of this embodiment, the incident end37of the second light guide27B facing the light source unit31is a circular end surface as shown inFIG.14, but the emission end29of the first light guide27A at the distal end portion17A is formed in the shape of an arc positioned around the distal end optical system50as shown inFIG.15for the convenience of the disposition of components at the distal end portion17A. Accordingly, it is difficult to dispose the lens member27C at the distal end portion17A. On the other hand, since there is no component that hinders the disposition of the lens member27C in the operation unit18, it is easy to dispose the lens member27C in the operation unit18.

The lens member27C is a lens for preventing a reduction in the amount of illumination light that is guided by the first light guide27A and the second light guide27B and that is emitted from the emission end29, and deterioration in the distribution of the illumination light. Specifically, the lens member27C is a lens for suppressing a variation in the relative intensity of each color light of the illumination light, which is guided by the first light guide27A and the second light guide27B and is emitted from the emission end29, with respect to a light distribution angle.

Graphs shown inFIGS.16and17are the measurement results of the illumination characteristics showing the relative intensity of each color light (LED light) of the illumination light with respect to a light distribution angle at a position (FIG.16) in the light guide27where the illumination light does not yet pass through the lens member27C and at a position (FIG.17) in the light guide27where the illumination light has passed through the lens member27C. The relative intensity mentioned here is a ratio of the intensity of each color LED light at a light distribution angle other than 0° to the intensity of each color LED light at a light distribution angle of 0° in a case where the intensity of each color LED light at a light distribution angle of 0° is set as 1. The intensity of light is the density of the luminous flux of light within a unit solid angle.

As shown inFIG.16, a violet light V, a blue light B, a green light G, and a red light R, which are LED lights emitted from the light source unit31and guided by the second light guide27B, have variations in relative intensity with respect to a light distribution angle at a position where the illumination light does not yet pass through the lens member27C, specifically, at the emission end of the second light guide27B. Particularly, a variation in relative intensity at a light distribution angle of about ±25° is large.

On the other hand, as shown inFIG.17, a violet light V, a blue light B, a green light G, and a red light R, which are LED lights emitted from the light source unit31and guided by the light guide27, have the same relative intensity with respect to a light distribution angle at a position where the illumination light has passed through the lens member27C, specifically, at the emission end29of the first light guide27A. That is, a variation in relative intensity can be suppressed. The same relative intensity mentioned here means that a difference in the relative intensities of the respective color lights of the illumination light with respect to a light distribution angle is very small, and it is preferable that all the relative intensities of a violet light V, a blue light B, and a red light R have a difference of ±5% or less from the relative intensity of a green light G in a case where the relative intensity of a green light G is used as a reference.

As described above, in this embodiment, the light guide27includes the first light guide27A, the second light guide27B, and the lens member27C, and the first light guide27A, the second light guide27B, and the lens member27C are fixed in the operation unit18. Accordingly, the positions of the optical axes of the first light guide27A, the second light guide27B, and the lens member27C are not shifted from each other. For this reason, the light guide27can prevent a reduction in the amount of illumination light and deterioration in the distribution of the illumination light by the lens member27C regardless of the operation state of the endoscope12.

Further, the endoscope12connects the first light guide27A to the second light guide27B in the operation unit18. In a case where the first light guide27A and the second light guide27B are connected to each other in the distal end portion17A of the insertion unit17or in the endoscope-side connector22, the length of one of the first light guide27A and the second light guide27B is significantly lengthened (the length is substantially the same as a total length from the distal end portion17A to the endoscope-side connector22, for example, 3.5 m). For this reason, it is difficult to handle the endoscope, and the ease of assembly of the endoscope is poor. On the other hand, since the first light guide27A and the second light guide27B are connected to each other in the operation unit18in the present invention, the lengths of the first light guide27A and the second light guide27B are not extremely lengthened (for example, the length of one of the first light guide27A and the second light guide27B can be set to 0.5 m, and the length of the other thereof can be set to 3.0 m). Accordingly, the ease of assembly of the endoscope12is improved.

An endoscope to be used as a laparoscope has been described in the above-mentioned embodiment by way of example, but the present invention can also be applied to, for example, endoscopes used for other uses, such as an industrial use, and the like. Further, the endoscope comprises two light guides as the light guide part in the above-mentioned embodiment, but may comprise three or more light guides.