JP2012120702A - Endoscope and endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain excellent image quality when performing illumination by excitation light and fluorescence coaxially with an objective optical system.SOLUTION: An electronic endoscope 10 includes an objective optical system 40 for capturing the image of a region to be observed and a first illumination optical system. An optical axis of excitation light emitted from a light guide 42 and an optical axis of white light generated by the fluorescence of a phosphor of a wavelength conversion member 49 excited and emitted by the excitation light are matched with each other. The wavelength conversion member 49 constitutes a diaphragm 44 together with an excitation light pass filter 48 and is disposed more on an object side than the excitation light pass filter 48 practically in charge of a function of the diaphragm. The light guide 42 is positioned behind a prism 45, and the excitation light is transmitted through an excitation pass filter 47 provided on a slope of the prism 45 and the excitation light pass filter 48 of the diaphragm 44 and applied to the wavelength conversion member 49. Since the excitation light and the fluorescence are not mixed in the image of the region to be observed, the excellent image quality of an observation image is maintained.

Description

  The present invention relates to an objective optical system that captures an image of a region to be observed of a subject, an endoscope that is coaxial with an illumination optical system that irradiates illumination light to the region to be observed, and an endoscope system including the endoscope.

  Inspection using an endoscope is widely used in the medical and industrial fields. As is well known, the endoscope irradiates the observation site of the subject with illumination light from the distal end of the insertion portion to be inserted into the subject, and captures an image of the observation site. Conventionally, a xenon lamp or a metal halide lamp has been used as a light source of illumination light, but in order to promote further miniaturization and cost reduction, a movement to adopt a light emitting diode or a semiconductor laser diode as a light source has been activated. When such a light source is used, the phosphor is excited by excitation light (blue light or ultraviolet light) emitted from the light source to generate fluorescence of green, yellow, red, etc., and the excitation light and fluorescence are combined. It produces white light.

  In standard endoscopes currently on the market, an objective optical system that captures an image of a site to be observed and an illumination optical system that irradiates illumination light to the site to be observed are independent of each other. For example, the objective optical system is arranged at the center of the tip, and the illumination optical system is arranged on both sides thereof. In this way, if the optical axes of the objective optical system and the illumination optical system do not match, the observation light of the objective optical system is only slightly irradiated when the tip is brought close to the observation site to some extent, and the observation image There was a problem that became dark. In order to solve this problem, an endoscope in which an objective optical system and an illumination optical system are coaxial has been proposed (see Patent Document 1).

  An endoscope described in Patent Document 1 includes a rod lens for transmitting an image of a site to be observed to an image sensor, a half mirror provided in an optical path from the exit end surface of the rod lens to the image sensor, and a half mirror. And a light source for irradiating illumination light toward the lens, and the illumination light is incident on the exit end face of the rod lens by a half mirror. That is, an objective optical system such as a rod lens and an illumination optical system such as a light source are coaxial. In order to prevent illumination light from entering the image sensor, an absorption screen is provided on the back side of the half mirror.

Japanese Patent Laid-Open No. 04-229816

  When the objective optical system and the illumination optical system are made coaxial as in Patent Document 1 and so-called coaxial illumination is performed, the illumination light is mixed into the image of the observed site and flare or the like (when a CCD is used for the image sensor) It is necessary to prevent image quality degradation such as smear or blooming. In Patent Document 1, a light absorbing screen is provided on the back side of the half mirror as a countermeasure. However, since a rod lens is used, the occurrence of flare is unavoidable.

  Moreover, Patent Document 1 does not assume a configuration in which a light emitting diode or a semiconductor laser diode is used as a light source and white light is generated by excitation light and fluorescence. In this case, it is necessary to take measures to prevent both excitation light and fluorescence from being mixed into the image of the site to be observed, but the specific method is not described in Patent Document 1 of course.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to maintain good image quality when illumination with excitation light and fluorescence is performed coaxially with the objective optical system.

  In order to achieve the above object, an endoscope according to the present invention includes an objective optical system having a diaphragm for limiting the amount of incident light of an image of an observation site of a subject, and a wavelength conversion member using light in a first wavelength band. A first illumination optical system that excites a phosphor to generate light in a second wavelength band and irradiates an observation site with illumination light that is combined with light in the first and second wavelength bands, and The optical axes of the objective optical system and the first illumination optical system are the same, and a wavelength conversion member is disposed on the objective side with respect to the stop.

  It is preferable that the objective optical system has a prism that refracts an image of a region to be observed at the rear stage of the stop, and a narrow-pass filter that selectively transmits only light in the first wavelength band on the slope of the prism. The light in the first wavelength band is emitted from behind the slope, passes through the narrow pass filter, and is partially irradiated to the wavelength conversion member. Of the image of the site to be observed, light of a wavelength band component different from the light of the first wavelength band is refracted by the prism, and light of the same wavelength band component as the light of the first wavelength band is transmitted through the narrow pass filter. And led behind the slope.

  It is preferable that the diaphragm is constituted by a narrow-pass filter that selectively transmits only light in the first wavelength band. The diaphragm and the wavelength conversion member may be integrated.

  It is preferable that an imaging device for capturing an image of the observed region is provided on the exit surface side of the image of the observed region of the prism. In this case, a cut filter that shields light in the first wavelength band may be provided between the exit surface of the image of the observation site of the prism and the imaging surface of the imaging element.

  It is preferable that the objective optical system and the first illumination optical system include a second illumination optical system having a different optical axis. In this case, the first illumination optical system alone or in combination with the second illumination optical system is used during near-field observation, and the second illumination optical system is used during normal observation. It is preferable that an operation means for selecting which of the first illumination optical system and the second illumination optical system is used is provided.

  The light in the first wavelength band is blue or ultraviolet light, the light in the second wavelength band is green, yellow, or red light, and the combined light of the light in the first and second wavelength bands is white light.

  An endoscope system according to the present invention excites a phosphor of a wavelength conversion member with an objective optical system having a diaphragm that restricts an incident light amount of an image of an observation site of a subject and light of a first wavelength band. It has an illumination optical system that generates light in two wavelength bands and irradiates an observation site with illumination light that is combined with light in the first and second wavelength bands, and has optical axes of the objective optical system and the illumination optical system. And an endoscope in which a wavelength conversion member is arranged on the object side of the stop, and a light source device that controls driving of a light source that emits light in the first wavelength band.

  According to the present invention, an objective optical system that captures an image of an observation site of a subject, light in the first wavelength band, and light in the second wavelength band that is excited and emitted from the phosphor of the wavelength conversion member by this light. Since the optical axis of the illumination optical system for irradiating the observation site with the combined illumination light is made the same, and the wavelength conversion member is arranged on the objective side relative to the stop of the objective optical system, the image quality can be kept good.

It is an external view which shows the structure of an electronic endoscope system. It is a top view which shows the end surface of the front-end | tip part of an electronic endoscope. It is sectional drawing which looked at the inside of a front-end | tip part from the side surface. It is a block diagram which shows the structure of an electronic endoscope system. 3 is a graph schematically showing spectral intensity distributions of white light, excitation light, and fluorescence, and spectral transmittances of an excitation light pass filter and an excitation light cut filter. It is sectional drawing which shows the example which has arranged the excitation light cut filter on the imaging surface of CCD.

  In FIG. 1, the electronic endoscope system 2 includes an electronic endoscope 10, a processor device 11, and a light source device 12. As is well known, the electronic endoscope 10 includes a flexible insertion portion 13 to be inserted into a subject (patient), an operation portion 14 connected to a proximal end portion of the insertion portion 13, and a processor device 11. And a connector 15 connected to the light source device 12, an operation unit 14, and a universal cord 16 that connects the connectors 15.

  The operation unit 14 includes an angle knob for bending the distal end portion 17 of the insertion unit 13 in the vertical and horizontal directions and an air supply / water supply nozzle 34 (see FIGS. 2 and 3) for supplying air and water. In addition to the air / water supply button, operation members such as a release button for recording an observation image as a still image are provided.

  Further, a forceps port through which a treatment tool such as an electric knife is inserted is provided on the distal end side of the operation unit 14. The forceps port communicates with a forceps outlet 33 (see FIGS. 2 and 3) provided at the distal end portion 17 through a forceps channel 58 (see FIG. 3) in the insertion portion 13.

  The processor device 11 is electrically connected to the light source device 12 and comprehensively controls the operation of the electronic endoscope system 2. The processor device 11 supplies power to the electronic endoscope 10 via the universal cord 16 and the transmission cable 57 (see FIG. 3) inserted into the insertion portion 13, and the CCD 41 (see FIG. 3) mounted on the distal end portion 17. ) Is controlled. Further, the processor device 11 receives the imaging signal output from the CCD 41 via the transmission cable 57, and performs various processes on the received imaging signal to generate image data. Image data generated by the processor device 11 is displayed as an observation image on a monitor 18 connected to the processor device 11 by a cable.

  In the electronic endoscope system 2, the near-field observation mode in which the distal end portion 17 of the insertion portion 13 is brought close to the observation site of the subject and the close-up view of the observation site is observed, and the distance between the observation site and the distal end portion 17 is appropriately set. A normal observation mode for observing while maintaining the screen is prepared. Each mode is switched by operating the mode switch 19 of the operation unit 14. The light source device 12 is equipped with a light source for each mode. In the near-field observation mode, the observation site is irradiated with blue excitation light (or ultraviolet light is acceptable) and white light by green to yellow to red fluorescence excited and emitted by the same optical axis as that of the objective optical system 40 (see FIG. 3). (Coaxial lighting). In the normal observation mode, white light from a xenon lamp or the like is irradiated from both sides of the optical axis of the objective optical system 40. The normal observation mode is automatically selected immediately after the electronic endoscope system 2 is turned on.

  2 and 3, an observation window (also a near-field observation illumination window) 30, normal observation illumination windows 31 and 32, a forceps outlet 33, and an air / water supply nozzle 34 are provided on the end surface 17 a of the distal end portion 17. It has been. The observation window 30 is disposed at the center on one side of the end face 17a. In the back of the observation window 30, an objective optical system 40 for capturing an image of the site to be observed, a CCD 41 for capturing an image of the site to be observed, and excitation light that is the source of illumination light for near-field observation from the light source device 12. An exit end of the light guide 42 for guiding light is disposed. As indicated by the one-dot chain line optical axis L, the optical axis of the light guide 42 (the optical axis of the illumination optical system) coincides with the optical axis of the objective optical system 40.

  The objective optical system 40 includes a lens group 43, a stop 44, and a prism 45. The lens group 43 and the stop 44 are accommodated in a lens barrel 46. The prism 45 is fixed to the rear end of the lens barrel 46, and refracts the image of the site to be observed by 90 ° and guides it to the imaging surface 41 a of the CCD 41. The prism 45 selectively transmits the excitation light path filter 47 (indicated by PF in FIG. 5) having two right angles, which selectively transmits only the excitation light emitted from the emission end of the light guide 42 (shields light other than the excitation light). The structure is sandwiched between the slopes of the prism.

  The stop 44 includes an excitation light path filter 48 on the prism 45 side and a wavelength conversion member 49 on the observation window 30 side (object side), and restricts the incidence of an image of the observed region. The excitation light path filter 48 is the same as the excitation light path filter 47 of the prism 45. Since the excitation light path filter 48 serves as a cut filter for light other than the excitation light, the excitation light path filter 48 substantially functions as a diaphragm.

  The excitation light emitted from the emission end of the light guide 42 passes through the excitation light pass filter 48 and partially enters the wavelength conversion member 49, and others pass through the aperture of the diaphragm 44. The wavelength conversion member 49 is glass in which a plurality of types of phosphors that absorb part of blue excitation light and emit light in green to yellow to red are dispersedly arranged or coated on the surface. The green to yellow to red fluorescence (indicated by F in FIG. 5) excited and emitted by the wavelength conversion member 49 and the blue light that does not contribute to the excitation light emission of the phosphor through the aperture of the diaphragm 44 and the excitation light pass filter 48. The excitation light is combined with each other to generate illumination light (white light) for near view observation, which is irradiated to the observation site through the observation window 30.

  The normal observation illumination windows 31 and 32 are arranged at symmetrical positions of the observation window 30. Behind the normal observation illumination windows 31 and 32 are the illumination lenses 50 and 51 (see FIG. 4) and the light guides 52 and 53 (see FIG. 4). Illumination light guided by the light guides 52 and 53 from 32 is irradiated to the site to be observed. The optical axes of the light guides 52 and 53 are parallel to the optical axis of the objective optical system 40.

  The CCD 41 is arranged so that an image of the observation site in the subject via the observation window 30 and the objective optical system 40 is incident on the imaging surface 41a. A color filter composed of a plurality of color segments, for example, a primary color (RGB) color filter in a Bayer array is formed on the imaging surface 41a.

  On the imaging surface 41a, a rectangular plate-like cover glass 55 is attached via a square frame-like spacer 54. The CCD 41, the spacer 54, and the cover glass 55 are assembled by being bonded to each other with an adhesive. Thereby, the imaging surface 41a is accommodated in the sealed space surrounded by the spacer 54 and the cover glass 55, and the imaging surface 41a is protected from intrusion of dust or water.

  A circuit board 56 is fixed to the rear end of the CCD 41. A plurality of terminals are provided at the rear end portion of the CCD 41 and the front end portion of the circuit board 56, and these are electrically connected by wire bonding or the like. The circuit board 56 is also provided with a terminal at the rear end, and the terminal and the transmission cable 57 are electrically connected by soldering or the like.

  In FIG. 4, the operation unit 14 of the electronic endoscope 10 is provided with an analog signal processing circuit (hereinafter abbreviated as AFE) 65, a CCD drive circuit 66, and a CPU 67. The AFE 65 includes a correlated double sampling circuit (hereinafter abbreviated as CDS), an automatic gain control circuit (hereinafter abbreviated as AGC), and an analog / digital converter (hereinafter abbreviated as A / D). The CDS performs correlated double sampling processing on the imaging signal output from the CCD 41, and removes reset noise and amplifier noise generated in the CCD 41. The AGC amplifies the image signal from which noise has been removed by CDS with a gain (amplification factor) specified by the processor device 11. The A / D converts the imaging signal amplified by the AGC into a digital signal having a predetermined number of bits. The imaging signal digitized by A / D is input to the image processing circuit 74 of the processor device 11 through the transmission cable 57.

  The CCD driving circuit 66 generates a driving pulse (vertical / horizontal scanning pulse, electronic shutter pulse, readout pulse, reset pulse, etc.) for the CCD 41 and a synchronization pulse for the AFE 65. The CCD 41 performs an imaging operation in accordance with the driving pulse from the CCD driving circuit 66 and outputs an imaging signal. Each part of the AFE 65 operates based on a synchronization pulse from the CCD drive circuit 66.

  After the electronic endoscope 10 and the processor device 11 are connected, the CPU 67 drives the CCD drive circuit 66 based on an operation start instruction from the CPU 70 of the processor device 11, and also uses the AFE 65 via the CCD drive circuit 66. Adjust the gain of AGC.

  The CPU 70 controls the overall operation of the processor device 11. The CPU 70 is connected to each unit via a data bus, an address bus, and a control line (not shown). The ROM 71 stores various programs (OS, application programs, etc.) and data (graphic data, etc.) for controlling the operation of the processor device 11. The CPU 70 reads out necessary programs and data from the ROM 71, develops them in the RAM 72, which is a working memory, and sequentially processes the read programs. Further, the CPU 70 obtains information that changes for each examination, such as examination date and time, character information such as patient and surgeon information, from the operation panel of the processor device 11 or a network such as a LAN (Local Area Network) and stores the information in the RAM 72. .

  The operation unit 73 is an operation panel provided on the housing of the processor device 11 or a known input device such as a mouse or a keyboard. The CPU 70 operates each unit according to operation signals from the operation unit 73 and the release button, the mode change switch 19, and the like in the operation unit 14 of the electronic endoscope 10.

  The image processing circuit 74 performs various types of image processing such as color interpolation, white balance adjustment, gamma correction, image enhancement, image noise reduction, and color conversion on the imaging signal input from the electronic endoscope 10.

  The display control circuit 75 receives graphic data in the ROM 71 and the RAM 72 from the CPU 70. The graphic data includes a display mask that hides the invalid pixel area of the observation image and displays only the effective pixel area, examination date and time, character information such as the patient, the operator, and the currently selected observation mode, a graphical user interface ( GUI; Graphical User Interface). The display control circuit 75 performs various display control processes such as a display mask, character information, GUI superimposition processing, and drawing processing on the display screen of the monitor 18 on the image from the image processing circuit 74.

  The display control circuit 75 has a frame memory that temporarily stores the image from the image processing circuit 74. The display control circuit 75 reads an image from the frame memory, and converts the read image into a video signal (component signal, composite signal, etc.) corresponding to the display format of the monitor 18. Thereby, an observation image is displayed on the monitor 18.

  In addition to the above, the processor device 11 includes a compression processing circuit for compressing an image in a predetermined compression format (for example, JPEG format), and the compressed image is stored in a CF card, a magneto-optical disk (MO), a CD- A media I / F for recording on removable media such as R, and a network I / F for controlling transmission of various data with a network such as a LAN are provided. These are connected to the CPU 70 via a data bus or the like.

  The light source device 12 includes a normal observation light source 80 and a foreground observation light source 81. The normal observation light source 80 is a light having a broad wavelength from blue to red, for example, a xenon lamp or a white LED (light emitting diode) that generates white light having a wavelength band of 480 nm to 750 nm as shown by W in FIG. It is. The near-field observation light source 81 is a semiconductor laser, LED, or the like that generates blue light having a light intensity only in the vicinity of 500 nm, for example, as indicated by E in FIG.

  The light sources 80 and 81 are driven by light source drivers 82 and 83, respectively. The condenser lenses 84 and 85 collect the light emitted from the light sources 80 and 81 and guide the light to the incident ends of the light guides 42, 52, and 53, respectively. Between the condensing lenses 84 and 85 and the light guides 42, 52, and 53, movable diaphragms 86 and 87 are provided for adjusting the amount of light incident on the incident ends of the light guides 42, 52, and 53. . The CPU 88 of the light source device 12 communicates with the CPU 70 of the processor device 11 and controls the operation of the light source drivers 82 and 83 and the movable diaphragms 86 and 87.

  When the normal observation mode is selected, the CPU 70 controls the driving of the light source driver 82 via the CPU 88 to turn on the normal observation light source 80. The illumination light applied to the site to be observed is normally white light from the observation illumination windows 31 and 32. On the other hand, when the foreground observation mode is selected, the normal observation light source 80 is turned off and the foreground observation light source 81 is turned on. The illumination light applied to the site to be observed becomes white light from the observation window 30 coaxial with the optical axis of the objective optical system 40. In the near view observation mode, the near view light source 81 may be turned on while the normal observation light source 80 is turned on, and white light may be emitted from both the normal observation illumination windows 31 and 32 and the observation window 30.

  Next, the operation of the electronic endoscope system 2 configured as described above will be described. When observing the inside of the subject with the electronic endoscope 10, the operator connects the electronic endoscope 10 and the devices 11 and 12, and turns on the power of the devices 11 and 12. Then, the operation unit 73 is operated to input information about the subject and instruct to start the examination.

  After instructing the start of the examination, the surgeon inserts the insertion portion 13 into the subject and illuminates the subject with illumination light from the light source device 12, and the monitor 18 displays an observation image in the subject with the CCD 41. Observe.

  The imaging signal output from the CCD 24 is subjected to various processes in each part of the AFE 65 and then input to the image processing circuit 74 of the processor device 11. The image processing circuit 74 performs various types of image processing on the input image pickup signal to generate an image. The image processed by the image processing circuit 74 is input to the display control circuit 75. In the display control circuit 75, various display control processes are executed in accordance with the graphic data from the CPU. As a result, the observation image is displayed on the monitor 18.

  When the inspection is performed by the electronic endoscope system 2, the foreground observation mode and the normal observation mode are switched according to the observation target. For example, when inserting the insertion unit 13 into the subject, the normal observation mode is selected, and an insertion operation is performed while observing an image obtained by irradiating a relatively distant view to ensure a wide field of view. When a lesion that requires detailed observation is found, the foreground observation mode is selected, and an image obtained by coaxial illumination with the distal end portion 17 approaching the lesion is observed. Then, if necessary, the release button is operated to acquire a still image, or when treatment is required for the lesion, various treatment tools are inserted into the forceps channel 58 to perform treatment such as excision of the lesion or medication.

  In the normal observation mode, the normal observation light source 80 is turned on under the instruction of the CPU 70, and illumination light is emitted from the normal observation illumination windows 31 and 32 arranged on the left and right of the observation window 30. Is done.

  On the other hand, when the foreground observation mode is selected, the normal observation light source 80 is turned off and the foreground observation light source 81 is turned on. Excitation light emitted from the near-field observation light source 81 is guided to the tip 17 by the light guide 42 and partially enters the wavelength conversion member 49 through the excitation light path filters 47 and 48 of the prism 45 and the stop 44. The excitation light incident on the wavelength conversion member 49 emits green to yellow to red fluorescence from the phosphor of the wavelength conversion member 49, and white light that combines the fluorescence and the excitation light that passes through the diaphragm 44 is the observation window 30. To the site to be observed.

  When the distal end portion 17 is brought close to the site to be observed to some extent (for example, several mm), the optical axis of the objective optical system 40 and the illumination optical system for normal observation are misaligned. This makes it difficult to ensure the brightness of the image necessary for observation. In such a case, by selecting the foreground observation mode and illuminating with the same optical axis as that of the objective optical system 40, it is possible to irradiate the observation site close to the distal end portion 17 with sufficiently bright illumination light, so that diagnosis is possible. A suitable observation image can be obtained.

  In the coaxial illumination, it is necessary to prevent light (excitation light and fluorescence in this example) other than the image of the site to be observed from entering the imaging surface 41a of the CCD 41 and becoming a noise component.

  In this example, the observation window 30 side of the stop 44 is configured by the phosphor-containing wavelength conversion member 49 and the prism 45 side is configured by the excitation light pass filter 48. Therefore, the fluorescence is shielded by the excitation light path filter 48 and is not incident on the prism 45 side. Not incident. Even if the fluorescent substance of the wavelength conversion member 49 is excited and emitted by light having the same wavelength band component as the excitation light included in the image of the site to be observed. For this reason, fluorescence does not enter the imaging surface 41 a of the CCD 41. In addition, the excitation light path filters 47 and 48 of the prism 45 and the stop 44 emit all of the excitation light other than that contributing to the excitation of the phosphor to the site to be observed through the observation window 30, and the reflected light is also reflected in each excitation light path filter. Since the light passes through the light guide 42 through the light emitting end side of the light guide 42, the excitation light does not enter the imaging surface 41 a of the CCD 41. That is, the noise component does not reach the image pickup surface 41a of the CCD 41, and only the image of the observed site reaches. Therefore, the image quality of the observation image can be kept good.

  Since the diaphragm 44 is integrally configured by the excitation light pass filter 48 and the wavelength conversion member 49, it is possible to contribute to downsizing of the objective optical system. Further, the excitation light pass filter 48 can effectively prevent the fluorescence from leaking to the prism 45 side.

  Since the normal observation mode and the foreground observation mode are prepared and each mode can be switched by operating the mode switch 19, an endoscopic examination suitable for the observation target and the operator's preference can be performed.

  Note that although the excitation light path filter 47 of the prism 45 transmits light having the same wavelength band component as that of the excitation light included in the image of the observation site, it passes through the light guide 42 on the emission end side and does not reach the imaging surface 41a. Originally, the color of the tissue in the living body is mainly red, and the blue component is very small. Therefore, even if light having the same wavelength band component as the excitation light included in the image of the observed site does not enter the imaging surface 41a, Does not affect image quality. In addition, although the amount of light of the combined light by excitation light and fluorescence is slightly lower than that of a xenon lamp or the like, the amount of light is not so high because it is for near-field observation.

  In order to prevent the excitation light from entering the imaging surface 41a more completely, an excitation light cut filter 95 may be provided on the imaging surface 41a as shown in FIG. As indicated by CF in FIG. 5, the excitation light cut filter 95 blocks light having a wavelength band component shorter than that of the excitation light (transmits light having a wavelength longer than that of the excitation light). The cover glass 55 may be used as the excitation light cut filter 95.

  The wavelength conversion member 49 only needs to be closer to the objective side than the diaphragm (excitation light path filter 48 in the above embodiment). For example, the function of the wavelength conversion member 49 may be provided at the edge of the observation window 30. However, in this case, some fluorescence is mixed in the image of the observed site. For this reason, the wavelength conversion member 49 is provided integrally with the diaphragm (excitation light path filter 48) as in the above-described embodiment, or the wavelength conversion member is close to the diaphragm because the fluorescence does not enter the imaging surface 41a. Is more preferable.

  In the above embodiment, the light source device 12 is mounted with the near view observation light source 81 and the excitation light is guided by the light guide 42. However, the light guide 42 is eliminated and the foreground observation light source 81 is mounted on the distal end portion 17. May be. Further, the normal observation illumination system itself such as the normal observation light source 80 and the light guides 52 and 53 may be omitted, and the electronic endoscope 10 may be configured with only the near view observation illumination system. A reduction in the diameter of the insertion portion 13 can be achieved.

  Note that the electronic endoscope system according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention. For example, the image sensor is not limited to the CCD of the above embodiment, and a CMOS image sensor may be used. Moreover, although the example which uses white light for each mode as an illumination light irradiated to a to-be-observed site was demonstrated, it is good also as a structure which irradiates the illumination light of a specific wavelength band. In this case, what normally emits light of a specific wavelength band to the observation light source and what emits and emits light of a specific wavelength band different from the excitation light may be employed for the phosphor of the wavelength conversion member.

  In the above embodiment, an electronic endoscope is exemplified, but the present invention is not limited to this, a fiberscope using an image guide, an ultrasonic endoscope in which an imaging element and an ultrasonic transducer are built in the tip, and the like. The present invention can also be applied to other types of endoscopes. Moreover, you may apply to the endoscope utilized not only for medical use but in an industrial field.

2 Electronic Endoscope System 10 Electronic Endoscope 11 Processor Unit 12 Light Source Unit 17 Tip 19 Mode Change Switch 30 Observation Window 31, 32 Normal Observation Illumination Window 40 Objective Optical System 41 CCD
42, 52, 53 Light guide 44 Aperture 45 Prism 47, 48 Excitation light path filter 49 Wavelength conversion member 67, 70, 88 CPU
80 Light source for normal observation 81 Light source for near view observation 95 Excitation light cut filter

Claims (10)

An objective optical system having a stop for limiting the amount of incident light of the image of the observed region of the subject;
The phosphor of the wavelength conversion member is excited with light in the first wavelength band to generate light in the second wavelength band, and the illumination light combined with the light in the first and second wavelength bands is applied to the site to be observed. A first illumination optical system for irradiating,
An endoscope, wherein the objective optical system and the first illumination optical system have the same optical axis, and a wavelength conversion member is disposed closer to the objective side than the stop. The objective optical system has a prism that refracts an image of a site to be observed at the rear stage of the stop,
The endoscope according to claim 1, wherein a narrow-pass filter that selectively transmits only light in the first wavelength band is provided on the slope of the prism.   The endoscope according to claim 1 or 2, wherein the diaphragm is configured by a narrow-pass filter that selectively transmits only light in the first wavelength band.   4. The endoscope according to claim 1, wherein the diaphragm and the wavelength conversion member are integrated.   The endoscope according to any one of claims 1 to 4, further comprising an image pickup device that picks up an image of the observed region on an exit surface side of the image of the observed region of the prism.   The endoscope according to claim 5, wherein a cut filter that shields light in the first wavelength band is provided between an exit surface of an image of an observation site of the prism and an imaging surface of the imaging element.   The endoscope according to any one of claims 1 to 6, further comprising a second illumination optical system having an optical axis different from that of the objective optical system and the first illumination optical system.   The endoscope according to claim 7, further comprising operation means for selecting which of the first illumination optical system and the second illumination optical system is used.   The light in the first wavelength band is blue or ultraviolet light, the light in the second wavelength band is green, yellow, or red light, and the combined light of the light in the first and second wavelength bands is white light The endoscope according to any one of claims 1 to 8. An objective optical system having a stop that limits the amount of incident light on the image of the observed region of the subject, and the light of the first wavelength band excites the phosphor of the wavelength conversion member to generate light of the second wavelength band. , Having an illumination optical system that irradiates an observation site with illumination light combined with light in the first and second wavelength bands, the objective optical system and the illumination optical system have the same optical axis, and the objective side from the stop An endoscope in which a wavelength conversion member is disposed,
An endoscope system comprising: a light source device that controls driving of a light source that emits light in a first wavelength band.

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