JP2005058620A - Endoscope system and endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope system which enables color photographing without lacking any color components at the time of normal image photographing and eliminating excitation light from incident light of a photography apparatus at the time of fluorescent image photographing even though one photography apparatus is used for both the normal image photography and the fluorescent image photography, and an endoscope which is incorporated in the above endoscope system. <P>SOLUTION: An insertion section 10a of an electronic endoscope 10 holds an elimination filter 17 which can be inserted and removed and eliminates an excitation light wavelength component in a light path of the object light between an object lens 12 and an image pickup device 15, and an operation section 10b has a change over lever 18 for the operation of the above insertion and removal. When the change over lever 18 is pushed to the side of a normal observation mode, the elimination filter 17 is removed from the light path and a light source processor apparatus 20 is changed into the normal observation mode, and when the change over lever 18 is pushed to the side of a special observation mode, the elimination filter 17 is inserted into the light path and the light source processor apparatus 20 is changed into the special observation mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an endoscope system and an endoscope for observing the inside of a body cavity such as a gastrointestinal tract or a bronchus.

  As is well known, biological tissue is excited to emit fluorescence when irradiated with light of a specific wavelength. In addition, an abnormal living tissue in which a lesion such as a tumor or cancer has occurred emits weaker fluorescence than a normal living tissue. This reaction phenomenon can also be caused by living tissue below the body cavity wall. In recent years, endoscope systems have been developed that detect abnormalities occurring in a living tissue under a body cavity wall using this reaction phenomenon.

As one of the endoscope systems, there is one having two imaging devices for imaging the inside of a body cavity into which the distal end of the endoscope is inserted (for example, see Patent Document 1). In this type of endoscope system, an image inside the body cavity (ordinary image) formed by illumination light reflected from the surface of the body cavity wall is taken by one imaging device, and a living tissue below the body cavity wall is emitted. An image inside the body cavity (fluorescence image) formed by fluorescence is taken by the other imaging device.
JP 09-117414 A

  However, the configuration including the two imaging devices as in the conventional endoscope system described above has a problem that the manufacturing cost of the endoscope system cannot be kept low. In addition, in the configuration provided with two imaging devices as described above, an optical path switching means for causing the light beam from the objective optical system in the endoscope to enter one of the imaging devices is necessary. Such optical path switching means is a cause of increasing the size of the endoscope system.

  In order to solve these problems, it is not unimaginable to adopt a configuration in which one image capturing apparatus is shared for normal image capturing and fluorescent image capturing. In adopting this configuration, in order to prevent the image inside the body cavity (stray light image) formed by the excitation light reflected by the surface of the body cavity wall from being mixed with the fluorescence image, it is necessary to connect the objective optical system to the imaging device. An optical filter for removing the excitation light must be arranged on the optical path. However, when using light having a part of the wavelength band in the visible band as excitation light, an image of a predetermined color component is obtained from a color image obtained during normal image observation by an optical filter that removes the excitation light. A new problem of being removed arises.

  In view of the above, an object of the present invention is to reduce the manufacturing cost and reduce the size by sharing one image capturing apparatus for normal image capturing and fluorescent image capturing. An endoscope system that can normally shoot color images without lacking components and that can appropriately remove only excitation light from light incident on the imaging device when capturing a fluorescent image, and an endoscope incorporated in such an endoscope system Is to provide.

  In order to solve the above problems, the endoscope system according to the present invention employs the following configuration.

  That is, this endoscope system is arranged at a switching lever for switching between the first observation mode and the second observation mode, a thin tubular insertion portion for insertion into a body cavity, and a proximal end of the insertion portion. And an operation unit having the switching lever, an objective optical system that forms an image in the body cavity when the distal end of the insertion part is inserted into the body cavity, and illumination light for illuminating the body cavity. A light source unit that emits excitation light for exciting the living tissue in the first observation mode and a light source unit that emits the excitation light in the second observation mode, and guides the illumination light or the excitation light emitted from the light source unit. Illumination optical system for emitting from the distal end of the insertion section, an imaging device for capturing an image of a body cavity formed by the objective optical system and outputting an image signal, and light having the same wavelength band as the excitation light For removing When the last filter and the switching lever are switched to the second observation mode side, the removal filter is inserted into the optical path from the objective optical system to the imaging device, and the switching lever is on the first observation mode side. And an insertion / extraction mechanism for extracting the removal filter from the optical path.

  When configured in this way, a removal filter for removing only light in the same wavelength band as the excitation light from the optical path from the objective optical system to the imaging device in accordance with the operation performed on the switching lever of the operation unit. Is inserted and removed. Further, light emitted from the distal end of the insertion portion is switched between illumination light and excitation light in accordance with an operation performed on the switching lever. That is, in the first observation mode, the optical filter is pulled out from the optical path and the illumination light is emitted from the tip of the insertion section. In the second observation mode, the optical filter is inserted into the optical path and the insertion section Excitation light is emitted from the tip.

  As a result, in the first observation mode, the light transmitted through the objective optical system among the illumination light reflected from the surface of the body cavity wall enters the imaging apparatus without removing light in any wavelength band. . In the second observation mode, the light transmitted through the objective optical system among the light including the excitation light reflected by the surface of the body cavity wall and the fluorescence emitted from the living tissue under the body cavity wall is the same as the excitation light. Only the light in the wavelength band is removed and enters the photographing apparatus.

  As a result, during the first observation mode, an image inside the body cavity (ordinary image) formed by the illumination light reflected from the surface of the body cavity wall is normally color-captured without any color component being lost, In the second observation mode, an image in the body cavity (fluorescence image) formed by fluorescence emitted from a living tissue under the body cavity wall is an image in the body cavity (fluorescence image) formed by excitation light reflected by the surface of the body cavity wall ( Color images are taken normally without including stray light images.

  At this time, one imaging device is shared by the imaging in the first observation mode and the imaging in the second observation mode. As a result, it is not necessary to use the optical path switching means, so that the manufacturing cost is reduced. Reduction and miniaturization will be achieved.

  In order to solve the above-described problems, the endoscope according to the present invention employs the following configuration.

  That is, this endoscope emits illumination light for illuminating the inside of a body cavity in the first observation mode, and includes a light source unit that emits excitation light for exciting biological tissue in the second observation mode. An endoscope connected to a processor device, the switching lever for switching between the first observation mode and the second observation mode, and a signal indicating an observation mode according to a state of the switching lever An output unit for outputting to the light source processor device, a thin tubular insertion unit for insertion into a body cavity, an operation unit disposed at a proximal end of the insertion unit and having the switching lever, and a distal end of the insertion unit An objective optical system that forms an image in the body cavity when the body is inserted into the body cavity, and illumination for guiding the illumination light or the excitation light emitted from the light source unit and emitting it from the distal end of the insertion unit Optical system An imaging device for capturing an image of a body cavity formed by the objective optical system in color and outputting an image signal; a removal filter for removing light having the same wavelength band as the excitation light; and the switching lever When switched to the second observation mode side, the removal filter is inserted into the optical path from the objective optical system to the imaging device, and when the switching lever is switched to the first observation mode side, And an insertion / extraction mechanism for extracting the removal filter.

  Therefore, if the endoscope is connected to a light source processor device including a light source unit that emits illumination light in the first observation mode and emits excitation light in the second observation mode, the endoscope described above can be used. It will function in the same manner as the endoscope incorporated in the endoscope system of the invention.

  As described above, according to the present invention, even when a single image capturing device is shared for normal image capturing and fluorescent image capturing, manufacturing cost reduction and downsizing can be achieved. Sometimes, some color components can be normally captured without any lack of color components, and only excitation light can be appropriately removed from light incident on the image capturing apparatus when capturing a fluorescent image.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an external view of an electronic endoscope system according to an embodiment of the present invention. FIG. 2 is a block diagram schematically showing this electronic endoscope system. The electronic endoscope system includes an electronic endoscope 10, a light source processor device 20, and a monitor 30.

  Although the detailed shape of the electronic endoscope 10 is not illustrated in FIG. 2, the electronic endoscope 10 includes a flexible tubular insertion portion 10 a that is inserted into a body cavity. A bending portion is incorporated at the distal end of the insertion portion 10a, and an operation portion 10b provided with an angle knob and various switches for operating the bending amount and the bending direction of the bending portion is provided at the base end. It has been.

  At least two through holes are formed in the distal end surface of the insertion portion 10a, and the light distribution lens 11 and the objective lens 12 are fitted in the pair of through holes, respectively.

  Further, the light guide 13 is passed through the insertion portion 10a. The light guide 13 is composed of a large number of flexible optical fibers, and the front end surface thereof faces the light distribution lens 11. Further, the base end of the light guide 13 is passed through the flexible tube 10c extending from the side surface of the operation unit 10b, and further, at the tip of the connector C provided at the tip of the flexible tube 10c, It is fixed.

  Further, a triangular prism 14 is incorporated in the insertion portion 10a. The triangular prism 14 is formed in the shape of a triangular prism whose bottom surface is a right triangle, and the inside of the inclined surface is configured as a reflecting surface that reflects light passing through the triangular prism 14. The triangular prism 14 is disposed in the vicinity of the objective lens 12 and bends the optical axis of the objective lens 12 at a right angle on the reflection surface (slope).

  Further, an image sensor 15 is incorporated in the insertion portion 10a. The imaging element 15 is a single-plate area image sensor having an imaging surface composed of a large number of pixels arranged two-dimensionally, and a primary color filter is on-chip on the imaging surface. The image pickup device 15 is disposed on the optical axis of the objective lens 12 bent by the triangular prism 14, and the image pickup surface is substantially located on the image plane of the objective lens 12.

  At least two signal lines 15 a and 15 b are connected to the image sensor 15. One signal line 15a is an electric wire for transmitting a drive signal for the image pickup device 15, and the other signal line 15b is an electric wire for transmitting an image signal output from the image pickup device 15.

  These signal lines 15a and 15b are sequentially passed through the insertion portion 10a and the flexible tube 10c. One signal line 15a is connected to the driver 16 in the connector C, and the other signal line 15b is It is fixed to the tip of the connector C. The driver 16 is a circuit that generates a drive signal for the image sensor 15 and outputs the drive signal to the image sensor 15.

  Further, a removal filter (excitation light cut filter) 17 is incorporated in the insertion portion 10a. The removal filter 17 is an optical filter that removes light in a wavelength band of about 440 nm to 460 nm and transmits light in other wavelength bands. The removal filter 17 is formed in a square flat plate shape, and is held so as to be insertable / removable with respect to the optical path of the subject light around the optical axis of the objective optical system 12 between the triangular prism 14 and the imaging device 15. ing.

  FIG. 3 is an explanatory view schematically showing a holding mechanism for holding the removal filter 17 so that it can be inserted and removed. The holding mechanism includes a rectangular frame 171 and a coil spring 172. The rectangular frame 171 has a pair of rectangular column-shaped short piece members 171a and 171b having substantially the same length as one side of the removal filter 17, and a pair of square columnar shapes having a length approximately twice that of the short piece members 171a and 171b. It consists of long piece members 171c, 171d, and is formed into a rectangular shape by joining the ends of these four members 171a-171d to each other.

  In the rectangular frame 171, the long piece members 171c and 171d are formed as rails by forming linear grooves on the inner surfaces facing each other, and a pair of the removal filter 17 is included in the pair of grooves. The side edges are respectively fitted. Thereby, the removal filter 17 can slide within the rectangular frame 171.

  The coil spring 172 is sandwiched between one short piece member 171b and one side edge of the removal filter 17, and urges the removal filter 17 toward the other short piece member 171a. The distal end of the wire 17a is connected to the center of the side edge of the removal filter 17 to which the coil spring 172 is applied, and the short end member 171b to which the coil spring 172 is applied is connected to the base end of the wire 17a. Is passed through a hole formed in the center.

  When the proximal end of the wire 17a is pulled in the direction away from the rectangular frame 171 (the direction of arrow A in FIG. 3), the removal filter 17 slides in that direction while the coil spring 172 is compressed. Conversely, when the tension of the wire 17a is relaxed in this state, the removal filter 17 slides in the direction opposite to the tension direction (the direction of arrow B in FIG. 3) by the elastic force of the coil spring 172.

  Since the holding mechanism is configured as described above, the removal filter 17 can be inserted into and removed from the optical path of the subject light between the triangular prism 14 and the image sensor 15. When the removal filter 17 is inserted in this optical path, the object light emitted from the triangular prism 14 is removed by the removal filter 17 with a wavelength component of about 440 nm to 460 nm, and then imaged by the image sensor 15. It will be incident on the surface. On the other hand, when the removal filter 17 is pulled out from the optical path, the subject light emitted from the triangular prism 14 is incident on the imaging surface of the imaging element 15 as it is.

  The wire 17a extending from the holding mechanism is drawn into the insertion portion 10a over the entire length. The proximal end of the wire 17 a is connected to a switching lever 18 provided in the operation unit 10 b of the electronic endoscope 10.

  FIG. 4 is an explanatory diagram for schematically explaining the switching lever 18. The switching lever 18 is formed in a rod shape. The switching lever 18 has a rotation shaft 18a orthogonal to the longitudinal direction at the base end, and is fixed in the operation portion 10b of the electronic endoscope 10 in a state of being rotatable around the rotation shaft 18a. Has been.

  The tip of the switching lever 18 is exposed to the outside through a slit (not shown) formed in the operation portion 10b, and the rotation range of the switching lever 18 is limited to a predetermined rotation angle range by this slit. ing. Further, a handle is attached to the tip of the switching lever 18.

  The proximal end of the wire 17 a extending from the removal filter 17 is connected to the central portion of the switching lever 18. Then, when the switching lever 18 is rotated around the rotation shaft 18a, the proximal end of the wire 17a is pulled or pulled back. In other words, when the switching lever 18 is operated, the removal filter 17 is inserted into and removed from the optical path of the subject light between the triangular prism 14 and the image sensor 15.

  Note that the switching lever 18 is always applied with a brake for restricting rotation around the rotation shaft 18a. The brake force is weaker than the operator's finger force, but is stronger than the spring force of the coil spring 172 for pushing the removal filter 17 back. Therefore, the switching lever 18 is not pulled back to the insertion portion 18a side by the elastic force of the coil spring 172.

  Further, a sensor 19 is attached to the switching lever 18. The sensor 19 outputs a signal when the switching lever 18 is at a position closest to the insertion portion 10a. In addition, a signal line 19a is connected to the sensor 19, and the base end of the signal line 19a is led through the flexible tube 10c and fixed to the distal end of the connector C.

  As illustrated in FIG. 2, the light source processor device 20 includes a timing control unit 21, a system control unit 22, an image processing unit 23, and a light source unit 24.

  Note that a connector receiver into which the connector C can be fitted is provided on the side surface of the housing of the light source processor device 20. When the connector C is fitted into the connector receptacle, the driver 16 in the connector C is connected to the timing control unit 21, the sensor 19a is connected to the system control unit 22 via the signal line 19a, and the electronic endoscope 10 is connected to the system control unit 22 through a signal line (not shown), the signal line 15b is connected to the image processing unit 23, and the base end of the light guide 13 is a light source. Enter part 24.

  The timing control unit 21 is a controller that generates various reference signals and controls the output of the signals. Various processes in the light source processor device 20 and the driver 16 in the connector C proceed according to this reference signal. Note that, in the light source processor device 20, the units 22 to 24 proceed with the processing with each set of two timings indicated by the reference signal as one cycle (for example, 1/30 second).

  The system control unit 22 is a controller that controls the entire light source processor device 20. The system control unit 22 is connected to various switches provided on the operation unit 10b of the electronic endoscope 10 and switches on an operation panel (not shown). When an input is received through these switches, the system control unit 22 receives the input. Perform the appropriate process.

  In addition, the system control unit 22 has a normal observation mode (first observation mode) and a special observation mode (first observation mode) depending on whether or not a signal is input from the sensor 19 attached to the switching lever 18 in the operation unit 10b. The observation mode is switched to any one of (2 observation modes).

  The image processing unit 23 constantly receives an image signal sent from the image sensor 15, performs various processes on the image signal, and outputs the processed signal to the monitor 30. Specifically, the image processing unit 23 includes a first stage processing circuit 231, a red component memory 232r, a green component memory 232g, a blue component memory 232b, a luminance component generation circuit 233, a first luminance component memory 234a, A two-luminance component memory 234b, an affected part image data generation circuit 235, a switch circuit 236, an adder 237, and a post-stage processing circuit 238 are provided.

  The first stage processing circuit 231 is a circuit for performing predetermined processing on the image signal sent from the image sensor 15. The processing performed on the image signal by the first stage processing circuit 231 includes high-frequency component removal, amplification, blanking, clamping, white balance, gamma correction, analog-digital conversion, and color separation. The first stage processing circuit 231 generates image data of each color component of red (R), green (G), and blue (B) by performing the above-described processing on the image signal.

  The first stage processing circuit 231 outputs the image data of each color component generated at the first timing in the one cycle to each color component memory 232r, 232g, 232b, and for each color component at the second timing. The data is not output to the memories 232r, 232g, and 232b. In addition, the first-stage processing circuit 231 outputs the image data of each color component sequentially generated at the first and second timings in one cycle to the luminance component generation circuit 233.

  The color component memories 232r, 232g, and 232b are memories for temporarily storing the RGB color component image data output from the first stage processing circuit 231. Each of these memories 232r, 232g, 232b outputs each color component image data at a timing according to the reference signal. However, while the R component image data is output to the adder 237, the G component image data and the B component image data are output to the post-processing circuit 238.

  The luminance component generation circuit 233 is a circuit that generates image data of the luminance component (Y component) in the YCrCb color space based on the RGB color component image data output from the first stage processing circuit 231. To explain conceptually, the luminance component generation circuit 233 expresses the gradation values (R, G, B) of pixels at the same position in the RGB color component image data as an equation of Y = 0.30R + 0.59G + 0.11B. By substituting and calculating, the luminance value Y of the pixel at that position is calculated.

  The luminance component generation circuit 233 outputs Y component image data based on the color component image data output from the first stage processing circuit 231 at the first timing in the one cycle to the first luminance component memory 234a. The Y component image data based on the color component image data output from the first stage processing circuit 231 at the second timing is output to the second luminance component memory 234b.

  Each of the luminance component memories 234a and 234b is a memory for temporarily storing Y component image data. Each of these memories 234a and 234b outputs each Y component image data to the affected part image data generation circuit 235 at a timing according to the reference signal.

  The affected area image data generation circuit 235 is a circuit that generates affected area image data based on each Y component image data output from each of the luminance component memories 234a and 234b. More specifically, the affected part image data generation circuit 235 first performs a normalization process for equalizing the gradation widths of both Y component image data, and then the gradations of pixels at the same position in both Y component image data. The absolute value of the difference between the values is calculated, and image data in which the absolute value of the difference between the pixels is the gradation value of itself is generated as the affected part image data.

  The switch circuit 236 is a circuit for opening and closing between the affected part image data generation circuit 235 and the adder 237. The switch circuit 236 is controlled by the system control unit 22 so that the affected part image data is not output to the adder 237 in the normal observation mode, and the affected part image data is output to the adder 237 in the special observation mode. Let

  The adder 237 is a circuit that adds the affected part image data to the R component image data only when the affected part image data is input. That is, the adder 237 passes the R component image data as it is to the post-processing circuit 238 in the normal observation mode, and passes the R component image data obtained by adding the affected part image data to the post-processing circuit 238 in the special observation mode. send.

  The post-stage processing circuit 238 uses the R component image data output from the adder 237 and the G component image data and B component image data output from the G component memory 232g and the B component memory 232b, respectively, for monitor output. It is a circuit for converting into an image signal. Processing performed on each color component image data in the post-processing circuit 238 includes digital-analog conversion, encoding, impedance matching, and the like. The post-processing circuit 238 generates a separate video signal and a composite video signal by performing the above-described processing on each color component image data, and outputs it to the monitor 30.

  When the monitor 30 receives the video signal output from the light source processor device 20, the monitor 30 displays a color image based on the video signal.

  The light source unit 24 is a unit for emitting light to be introduced into the base end surface of the light guide 13. Specifically, the light source unit 24 includes a lamp 241, a power supply circuit 242, a rotating plate 243, a first motor 244, a stage mechanism 245, a second motor 246, a movement driver 247, and a synchronization driver 248. ing.

  The lamp 241 is a light source that emits white light having a wavelength component in the entire visible band of about 400 nm to 700 nm toward the base end surface of the light guide 13. The power supply circuit 242 is a circuit that receives an instruction from the system control unit 22 and supplies power to the lamp 241 or stops the supply thereof.

  The rotating plate 243 includes a disk having a pair of through holes and an optical filter fitted in one through hole. FIG. 5 is a front view of the rotating plate 243. As shown in FIG. 5, a substantially semicircular through hole 243a is formed between the center of the rotating plate 243 and the outer peripheral edge thereof.

  Further, in the rotating plate 243, a substantially semicircular through hole is also formed in the remaining semicircular region, and an excitation light transmission filter 243b is fitted into the through hole. The excitation light transmission filter 243b is an optical filter for extracting excitation light for exciting biological tissue from white light. Specifically, the excitation light transmission filter 243b transmits light in a wavelength band of about 440 nm to 460 nm and transmits the remaining light. Remove light in the wavelength band. FIG. 6 is a spectroscopic diagram showing the relationship between the wavelength band and the visible band.

  The first motor 244 is an actuator for rotating the rotating plate 243 configured as described above, and its drive shaft is fixed to the center of the rotating plate 243 in a state where it coincides with the central axis of the rotating plate 243. Has been.

  The stage mechanism 245 is a mechanism for translating an object installed on the stage only in one direction, and a first motor 244 is installed on the stage. When the stage mechanism 245 is driven in the forward and reverse directions, the rotating plate 243 fixed to the drive shaft of the first motor 244 is inserted / removed perpendicularly to the optical path of white light emitted from the lamp 241.

  The second motor 246 is an actuator for driving the stage mechanism 245, and the moving driver 247 is a circuit for controlling the driving of the second motor 246 in response to an instruction from the system control unit 22. is there.

  The stage mechanism 245 is provided with a position sensor 247a for detecting the position of the stage, and the system control unit 22 detects the amount of movement of the stage based on a signal obtained from the position sensor 247a, The movement driver 247 is instructed to drive the second motor 246 until the stage reaches a predetermined position.

  More specifically, when the observation mode is switched to the normal observation mode, the system control unit 22 controls the second motor 246 through the moving driver 247 so that the rotating plate 243 is pulled out from the optical path of white light. Until the stage mechanism 245 is driven.

  Further, when the observation mode is switched to the special observation mode, the system control unit 22 controls the second motor 246 through the moving driver 247 so that the excitation light transmission filter 243b is rotated during the rotation of the rotating plate 243. The stage mechanism 245 is driven until the rotating plate 243 is disposed at a position where it is repeatedly inserted into the optical path of white light.

  The synchronization driver 248 is a circuit for controlling the driving of the first motor 244 according to the reference signal. An optical sensor 248a for detecting the rotation period of the rotating plate 243 is disposed in the vicinity of the outer peripheral edge of the rotating plate 243, and the synchronization driver 248 is based on a signal obtained from the optical sensor 248a. The rotation period of the rotating plate 243 is synchronized with the timing indicated by the reference signal. However, the means for detecting the rotation period of the rotating plate 243 may be an encoder assembled to the first motor 244 instead of the optical sensor 248a.

  In the special observation mode, the synchronization driver 248 inserts the through hole 243a of the rotating plate 243 into the optical path of white light in accordance with the first timing in the one cycle, and in accordance with the second timing. The excitation light transmission filter 243b is inserted into the optical path of white light. For this reason, in the special observation mode, white light is introduced into the base end surface of the light guide 13 at the first timing in the one cycle and excitation light is introduced at the second timing. FIG. 7 is an explanatory diagram showing the relationship between the introduction timing of white light and excitation light to the base end face of the light guide 13 and the field index pulse generated based on the reference signal.

  Since the electronic endoscope system of the present embodiment is configured as described above, an operator of this electronic endoscope system can observe the inside of the body cavity by the procedure as described below.

  First, the operator connects the electronic endoscope 10, the light source processor device 20, and the monitor 30, and turns on the light source processor device 20 and the monitor 30. Subsequently, the operator inserts the distal end of the insertion portion 10a of the electronic endoscope 10 into the body cavity, and moves the switching lever 18 in the operation portion 10b of the electronic endoscope 10 away from the insertion portion 10a (in FIG. 4). Tilt to the arrow A side) to switch to the normal observation mode.

  Then, the removal filter 17 is pulled out from the optical path of the subject light between the triangular prism 14 and the image sensor 15 in accordance with the operation performed on the switching lever 18. At the same time, the rotating plate 243 is pulled out from the optical path of white light emitted from the lamp 241. As a result, white light is always incident on the base end surface of the light guide 13, and the white light is continuously emitted from the distal end of the insertion portion 10a of the electronic endoscope 10 to illuminate the body cavity.

  Of the illumination light reflected from the surface of the body cavity wall, the light transmitted through the objective lens 12 is reflected by the triangular prism 14 and enters the imaging surface of the imaging element 15. At this time, an image (normal image) in the body cavity is formed on the imaging surface by the objective lens 12.

  The normal image formed on the image pickup surface is picked up by the image pickup device 15, and an image signal is output to the image processing unit 23. In the image processing unit 23, the first-stage processing circuit 231 performs predetermined processing on the image signal to generate image data of each color component of RGB. Each color component image data is output to the post-processing circuit 238 without adding the affected part image data, and is converted into a video signal which is an image signal for monitor output in the post-processing circuit 238. The video signal is output to the monitor 30.

  Therefore, a normal image is displayed on the monitor 30 as a color normal observation image. The operator can observe the state of the body cavity wall while viewing the normal observation image.

  Furthermore, the operator observes the special observation image obtained by using the excitation light for the part selected through observation of the normal observation image on the monitor 30. Specifically, the operator switches to the special observation mode by tilting the switching lever 18 in the operation unit 10b of the electronic endoscope 10 to the side close to the insertion unit 10a (arrow B side in FIG. 4).

  Then, the removal filter 17 is inserted in the optical path of the subject light between the triangular prism 14 and the image sensor 15 in accordance with the operation performed on the switching lever 18. At the same time, the rotating plate 243 is inserted into the optical path of white light emitted from the lamp 241. As a result, light in the wavelength band of white light and excitation light alternately and repeatedly enters the base end face of the light guide 13, and white light and excitation light are emitted from the distal end of the insertion portion 10 a of the electronic endoscope 10. It is alternately injected.

  During the period in which the white light is irradiated into the body cavity, the inside of the body cavity is illuminated. Of the illumination light reflected from the surface of the body cavity wall, the light transmitted through the objective lens 12 is reflected by the triangular prism 14 and light having a wavelength band of about 440 nm to 460 nm is removed by the removal filter 17. The light enters the imaging surface of the image sensor 15. At this time, an image (normal image) in the body cavity is formed on the imaging surface by the objective lens 12.

  On the other hand, during a period in which light having a wavelength band of about 440 nm to 460 nm is irradiated into the body cavity, the living tissue under the body cavity wall is excited to emit fluorescence, and this excitation light is reflected on the surface of the body cavity wall. Of the light including fluorescence and excitation light, the light transmitted through the objective lens 12 is reflected by the triangular prism 14, and then the light in the wavelength band of about 440 nm to 460 nm is removed by the removal filter 17. That is, excitation light is removed from light including fluorescence and excitation light. The fluorescence transmitted through the removal filter 17 is incident on the imaging surface of the imaging element 15. At this time, an image in the body cavity (fluorescence image) is formed on the imaging surface by the objective lens 12.

  The normal image and the fluorescence image alternately formed on the imaging surface are picked up by the image pickup device 15, and their image signals are sequentially output to the image processing unit 23. In the image processing unit 23, the first-stage processing circuit 231 performs predetermined processing on the image signal. At the first timing, each color component image data (normal image data) based on the normal image is stored in each color component memory 232r, 232g, 232b. The luminance component generation circuit 233 outputs the color component image data (fluorescence image data) based on the fluorescent image to the luminance component generation circuit 233 at the second timing.

  When the luminance component generation circuit 233 obtains each color component image data based on the normal image at the first timing, the luminance component generation circuit 233 converts the color component image data into luminance component image data and outputs the luminance component image data to the first luminance component memory 234a. When the data is acquired at the second timing, it is converted into luminance component image data and output to the second luminance component memory 234b. Then, based on the luminance component image data in the first and second luminance component memories 234a and 234b, the affected area image data generation circuit 235 generates affected area image data.

  Then, after the affected part image data is added to the R component image data in each color component image data based on the normal image, each color component image data is converted into a video signal which is an image signal for monitor output in the post-processing circuit 238. This video signal is output to the monitor 30.

  For this reason, a special image generated based on the normal image and the fluorescent image is displayed on the monitor 30 as a color special observation image. The operator can identify the contours and irregularities of the body cavity wall while looking at the special observation image, and a biological body that emits relatively weak fluorescence due to the red spots in the image as spots or lumps. A group of tissues, that is, a site where a lesion such as a tumor or cancer is highly likely to be recognized can be recognized.

  As described above, in the electronic endoscope system according to the present embodiment, one image pickup device 15 is shared for normal image capturing and fluorescent image capturing. For this reason, the manufacturing cost is reduced as compared with a conventional endoscope system having two imaging devices. However, the electronic endoscope system according to the present embodiment does not need to be provided with an optical path switching unit for inputting light transmitted through the objective lens 12 to any one of the imaging elements. For this reason, the electronic endoscope system of the present embodiment is downsized as compared with the conventional endoscope system.

  Furthermore, in the electronic endoscope system of the present embodiment, a removal filter for removing excitation light from the optical path of subject light centered on the optical axis of the objective lens 12 between the triangular prism 14 and the image sensor 15. 17 can be inserted / removed. However, the insertion / removal can be easily performed by the switching lever 18 in the operation unit 10b of the electronic endoscope 10, and in addition, the normal image can be changed according to the switching operation. Shooting and fluorescent image shooting are switched automatically.

  For this reason, when capturing a normal image, the wavelength component of the excitation light is not removed from the light input to the image sensor 15, and therefore the electronic endoscope system of the present embodiment lacks any color component. Therefore, normal images can be captured normally in color. In addition, since only the excitation light is necessarily removed from the light incident on the image pickup device 15 when the fluorescent image is taken, according to the electronic endoscope system of this embodiment, the excitation light reflected by the surface of the body cavity wall is formed. The image inside the body cavity (stray light image) is not mixed with the fluorescent image.

External view of electronic endoscope system according to this embodiment Configuration diagram schematically showing an electronic endoscope system Configuration diagram schematically showing a holding mechanism for holding an optical filter so that it can be inserted and removed Explanatory diagram for schematically explaining the switching lever Front view of rotating plate Spectrograph for explaining the wavelength band and visible band of illumination light Explanatory drawing which shows the relationship between the emission timing of the white light and excitation light to a light guide, and a field index pulse

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic endoscope 11 Light distribution lens 12 Objective lens 13 Light guide 14 Triangular prism 15 Imaging element 15a Signal line 15b Signal line 16 Driver 17 Removal filter 171 Rectangular frame 172 Coil spring 17a Wire 18 Switching lever 18a Rotating shaft 19 Sensor 19a Signal line DESCRIPTION OF SYMBOLS 20 Light source processor apparatus 21 Timing control part 22 System control part 23 Image processing part 24 Light source part 241 Lamp 243 Rotating plate 243a Through hole 243b Excitation light transmission filter 244 1st motor 245 Stage mechanism 246 2nd motor 247 Movement driver 248 For synchronization Driver 30 Monitor

Claims (8)

A switching lever for switching between the first observation mode and the second observation mode;
A tubular insertion portion for insertion into a body cavity;
An operation unit disposed at a proximal end of the insertion unit and having the switching lever;
An objective optical system that forms an image in the body cavity when the distal end of the insertion portion is inserted into the body cavity;
A light source unit that emits illumination light for illuminating the inside of the body cavity in the first observation mode, and emits excitation light for exciting biological tissue in the second observation mode;
An illumination optical system for guiding the illumination light or the excitation light emitted from the light source unit and emitting it from the tip of the insertion unit;
An imaging device for taking an image of a body cavity formed by the objective optical system in color and outputting an image signal;
A removal filter for removing light in the same wavelength band as the excitation light;
When the switching lever is switched to the second observation mode side, the removal filter is inserted in the optical path from the objective optical system to the imaging device, and the switching lever is switched to the first observation mode side. An endoscope system comprising: an insertion / extraction mechanism that extracts the removal filter from the optical path. The endoscope system according to claim 1, wherein the light source unit emits the illumination light and the excitation light alternately in the second observation mode. In the second observation mode, an image signal acquired from the imaging device during a period in which the light source unit emits the illumination light, and an image acquired from the imaging device in a period in which the light source unit emits the excitation light. The endoscope system according to claim 2, further comprising an image processing unit that generates an image signal for displaying an image showing a position that can be estimated as an affected part based on the signal. The endoscope system according to claim 1, 2 or 3, wherein the imaging device, the removal filter, and the insertion / extraction mechanism are arranged in the vicinity of a distal end of the insertion portion. The endoscope system according to claim 4, wherein the insertion / extraction mechanism is connected to the switching lever via a wire drawn through the insertion portion of the endoscope. The endoscope system according to any one of claims 1 to 5, wherein the illumination optical system is disposed inside the insertion portion. The endoscope system according to claim 1, wherein the imaging device is an imaging device that captures an image of a body cavity formed by the objective optical system and outputs an image signal. . Illumination light for illuminating the body cavity is emitted in the first observation mode, and is connected to a light source processor device including a light source unit that emits excitation light for exciting the living tissue in the second observation mode. An endoscope,
A switching lever for switching between the first observation mode and the second observation mode;
An output unit that outputs a signal indicating an observation mode according to a state of the switching lever to the light source processor device;
A tubular insertion portion for insertion into a body cavity;
An operation unit disposed at a proximal end of the insertion unit and having the switching lever;
An objective optical system that forms an image in the body cavity when the distal end of the insertion portion is inserted into the body cavity;
An illumination optical system for guiding the illumination light or the excitation light emitted from the light source unit and emitting it from the tip of the insertion unit;
An imaging device for taking an image of a body cavity formed by the objective optical system in color and outputting an image signal;
A removal filter for removing light in the same wavelength band as the excitation light;
When the switching lever is switched to the second observation mode side, the removal filter is inserted in the optical path from the objective optical system to the imaging device, and the switching lever is switched to the first observation mode side. And an insertion / extraction mechanism for extracting the removal filter from the optical path.

Images