JP5271364B2 - Endoscope system - Google Patents

Abstract

The invention discloses an endoscope system, wherein an LPF turntable and an SPF turntable are arranged in a wide-band light path (BB). The LPF turntable is provided with a first LPF and a second LPF, wherein the lower limits of the wavelengths of the first and second LPFs are different from each other. The SPF turntable is provided with a first SPF and a second SPF, wherein the upper limits of the wavelengths of the first and second LPFs are different from each other. The wide-band light (BB) can pass through the LPFs and the SPFs, so that a blue arrow-band light with a predetermined half-value width is generated.

Description

  The present invention relates to an endoscope system that performs special light observation using light of a specific wavelength.

  In recent years, endoscope systems that can perform so-called special light observation, such as irradiating a living tissue with light of a specific narrow wavelength band (narrowband light) to obtain an observation image in which blood vessels in the living tissue are emphasized, are known. (For example, refer to Patent Document 1). Since the light absorption spectrum of a blood vessel (hemoglobin) has an absorption peak in the band near 415 nm, in this endoscope system, as a narrow band light, a blue narrow band having a wavelength in a band with a high light absorption rate near 415 nm. Light is used as illumination light.

  When using blue narrowband light corresponding to a band where the light absorption rate of blood vessels (hemoglobin) is high, in the observation image, the blood vessel part is dark because light is absorbed, and it is not absorbed by the surrounding tissue of the blood vessel, but scattered, Reflects brightly to reflect. By narrowing the illumination light, the wavelength outside the band with high light absorptance is removed from the illumination light, so that the components scattered and reflected in the blood vessel portion are reduced, and the contrast between the blood vessel and the surrounding tissue is enhanced. An observed image can be obtained.

Japanese Patent Laid-Open No. 2001-170009

  During special light observation, the distance between the distal end portion of the endoscope and the living tissue is changed by moving the distal end portion of the endoscope in which the image sensor is built. As a result, the brightness of the observation image changes. For example, in the case of distant view observation in which the endoscope distal end is observed at a position away from the biological tissue in contrast to the near view observation in which the endoscope distal end is observed at a position close to the biological tissue, the amount of light is insufficient. The whole screen becomes dark. For this reason, it is necessary to increase the amount of blue narrow-band light during distant view observation, but conversely, during near-field observation, it is bright enough to highlight the surface blood vessels and so on. May be difficult to see.

  To solve this problem, there is a method of changing the amount of blue narrow band light by changing the half-value width or wavelength band of blue narrow band light according to the distance between the endoscope distal end and the living tissue. Conceivable. However, although LEDs and LDs used as blue narrow band light sources can emit light of a specific wavelength, they cannot change the half-value width or wavelength band of the emitted light.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an endoscope system capable of obtaining a good observation image regardless of conditions such as near view observation and distant view observation.

  The present invention has been made to achieve the above object, and includes a broadband light source that emits white broadband light, and a short-pass filter that transmits light having a wavelength equal to or less than a predetermined upper limit wavelength among the broadband light; A long-pass filter that passes light having a wavelength equal to or greater than a predetermined lower-limit wavelength among the broadband light, and further includes a plurality of at least one of the long-pass filters, and a set of the short-pass filter and the long-pass filter A filter unit that generates narrowband light having a specific wavelength band used for special light observation by inserting a filter into the optical path of the broadband light and allowing the broadband light to pass through, and the narrowband light irradiated Imaging means for imaging the site to be observed, and the filter unit allows the broadband light to pass through. By changing the ® over Topas filter and the combination of the long-pass filter, characterized by changing the amount of the narrow band light.

  The filter unit selectively selects the plurality of short-pass filters having different upper-limit wavelengths, the plurality of long-pass filters having different lower-limit wavelengths, each of the short-pass filters, and any of the long-pass filters. And a filter insertion means for inserting into the optical path.

  Preferably, the filter unit emits a plurality of the narrow band lights having different light amounts by changing a combination of the short pass filter and the long pass filter inserted into the optical path by the filter insertion unit. Moreover, it is preferable that each said narrow-band light differs in a half value width. Furthermore, it is preferable that each narrow-band light has a different center wavelength.

  Based on an imaging signal acquired by imaging of the imaging unit, a distance determination unit that determines the distance between the distal end portion of the endoscope and the site to be observed, and the distance determined by the distance determination unit increases as the distance determined by the distance determination unit increases. It is preferable to include an insertion control unit that controls the filter insertion unit to switch a combination of the short-pass filter and the long-pass filter to be inserted into the optical path so that the half-value width of the narrowband light is expanded.

  The filter unit includes a first short-pass filter and a first long-pass filter that generate first narrow-band light, and a second short-pass filter that generates second narrow-band light having a wavelength band different from that of the first narrow-band light. And a second long pass filter, and the filter insertion means selects any one of the first short pass filter and the first long pass filter, the second short pass filter and the second long pass filter. Therefore, it is preferable to insert into the optical path.

  The filter unit has a plurality of the first short pass filters having different upper limit wavelengths and a plurality of the first long pass filters having different lower limit wavelengths, and is inserted into the optical path by the filter insertion means. Preferably, the amount of the first narrowband light is changed by changing a first combination of the first short pass filter and the first long pass filter.

  The filter unit includes a plurality of second short pass filters having different upper limit wavelengths and a plurality of second long pass filters having different lower limit wavelengths, and is inserted into the optical path by the filter insertion means. Preferably, the amount of the second narrowband light is changed by changing a second combination of the second short pass filter and the second long pass filter.

  Based on an imaging signal acquired by imaging of the imaging means, the distance determining means for determining the distance between the distal end portion of the insertion portion of the endoscope and the site to be observed is provided, and the insertion control means includes the distance The filter insertion means is controlled to switch between the first and second combinations so that the half-value widths of the first to second narrowband lights increase as the distance determined by the determination means increases. preferable.

  The first narrowband light is blue narrowband light corresponding to a wavelength band having a large amount of absorption on the short wavelength side of the light absorption spectrum of hemoglobin, and the second narrowband light is on the long wavelength side of the absorption spectrum. It is preferably green narrowband light corresponding to a wavelength band having a large amount of absorption.

  The endoscope system of the present invention can change the light quantity of the narrow band light irradiated to the observation site by changing the combination of the short pass filter and the long pass filter that allows the broadband light to pass. The amount of narrowband light can be changed in response to changes in the distance to the site to be observed. As a result, a good observation image can be obtained in both the near-field observation and the far-field observation.

It is a schematic diagram of an endoscope system. It is a block diagram which shows the electric constitution of an endoscope system. It is a front view of a filter for normal observation (UOF). It is a front view of a long pass filter (LPF) turret. It is a graph which shows the light transmission characteristic of 1st LPF and 2nd LPF. It is a front view of a short pass filter (SPF) turret. It is a graph which shows the light transmission characteristic of 1st SPF and 2nd SPF. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrow-band light in 1st distance observation mode. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrow-band light in 2nd distance observation mode. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrow-band light in 3rd distance observation mode. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrow-band light in 4th distance observation mode. It is explanatory drawing of a data table. It is a flowchart which shows the flow of the process of special light observation in an endoscope system. It is a front view of the LPF turret of 2nd Embodiment. It is a graph which shows the light transmission characteristic of the 1st-2nd LPF of 2nd Embodiment. It is a front view of SPF of 2nd Embodiment. It is a graph which shows the light transmission characteristic of SPF of 2nd Embodiment. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrowband light in the foreground observation mode of 2nd Embodiment. (A)-(C) are explanatory drawings for demonstrating emission | emission of narrow-band light in the distant view observation mode of 2nd Embodiment. It is explanatory drawing of the data table of 2nd Embodiment. It is a block diagram which shows the electric constitution of the endoscope system of 3rd Embodiment. It is a front view of the LPF turret of 3rd Embodiment. It is a front view of the SPF turret of 3rd Embodiment. It is a flowchart which shows the flow of the process of special light observation in 3rd Embodiment. (A)-(C) are explanatory drawings for demonstrating emission | emission of green narrow-band light in 1st distance observation mode. (A)-(C) are explanatory drawings for demonstrating emission | emission of green narrow-band light in 4th distance observation mode.

[First Embodiment]
As shown in FIG. 1, an endoscope system 10 includes an electronic endoscope 11 that captures an inside of a patient's digestive tract and trachea (observed site), and an imaging signal obtained by the electronic endoscope 11. Is provided with a processor device 12 for generating an observation image in the tube, a light source device 13 for supplying illumination light for illuminating the inside of the tube to the electronic endoscope 11, and a monitor 14 for displaying the observation image.

  In the endoscope system 10, a normal observation mode in which the inside of the tube is entirely observed by illuminating the inside of the tube with broadband light such as white light, and a state in which the inside of the tube is illuminated with narrowband light and the surface blood vessels are highlighted. There are two observation modes: a special light observation mode for observation. In the special light observation mode, the first distance observation mode, the second distance observation mode, the third distance observation mode, and the fourth distance are selected according to the distance between the distal end portion of the electronic endoscope 11 and the living tissue in the tube. There are a total of four sub-observation modes of the observation mode. Among these, the first to second distance observation modes are so-called foreground observation modes in which observation is performed in a foreground state where the distance to the living tissue is short. The third to fourth distance observation modes are so-called distant view observation modes in which observation is performed in a distant view state where the distance from the living tissue is long.

  The electronic endoscope 11 is connected to a flexible insertion portion 16 to be inserted into a tube and a proximal end portion of the insertion portion 16, and is used for gripping the electronic endoscope 11 and operating the insertion portion 16. And a universal cord 18 for connecting the operation unit 17 to the processor device 12 and the light source device 13, respectively.

  The insertion portion distal end portion 16a that is the distal end portion of the insertion portion 16 incorporates an optical system, an image sensor, and the like that are used for illumination inside the tube and photographing. Further, in addition to the observation window 19 (see FIG. 2) and the illumination window 20 (see FIG. 2), an air / water supply nozzle, which is not shown, is inserted into the distal end surface of the insertion portion distal end portion 16a. A forceps outlet or the like serving as an outlet of the forceps channel is provided. A bendable bending portion 16b is connected to the rear end of the insertion portion distal end portion 16a.

  The operation unit 17 is provided with an angle knob 21, an operation button 22, a forceps inlet 23, and the like. The angle knob 21 is rotated when adjusting the bending direction and the bending amount of the insertion portion 16. The operation button 22 is used for various operations such as air / water supply and suction. The forceps inlet 23 communicates with the forceps channel.

  The universal cord 18 incorporates an air / water channel, a signal cable, a light guide, and the like. A connector portion 25 a is provided at the distal end portion of the universal cord 18. This connector portion 25 a is connected to the light source device 13. Further, the connector part 25b branches from the connector part 25a. This connector portion 25 b is connected to the processor device 12.

  As shown in FIG. 2, the light source device 13 includes a broadband light source 30, a normal observation filter (UOF) turret 31 used in the normal observation mode, and a long pass filter (UOF) used in the special light observation mode. An LPF (Long Pass Filter) turret 32, a short pass filter (SPF) turret 33, a turret shift mechanism 34, a turret rotation mechanism 35, and a condenser lens 36 are provided. Here, the LPF turret 32, the SPF turret 33, and the turret rotation mechanism 35 correspond to the filter insertion means of the present invention.

  The broadband light source 30 is, for example, a xenon lamp, a white LED, a micro white light source, or the like, and generates white broadband light BB having a wavelength ranging from a red region to a blue region (about 470 to 700 nm). The broadband light source 30 always emits broadband light BB during endoscopic examination.

  A part of the UOF turret 31 is inserted into the optical path of the broadband light BB emitted from the broadband light source 30 in the normal observation mode. Further, a part of the LPF turret 32 and the SPF turret 33 are simultaneously inserted into the optical path of the broadband light BB in the special light observation mode.

  As shown in FIG. 3, the UOF turret 31 includes a blue filter 37B, a green filter 37G, and a red filter 37R provided along the circumferential direction of the rotation shaft 31a. The blue filter 37B transmits blue band light (B light) out of the broadband light BB. The green filter 37G transmits green band light (G light) out of the broadband light BB. The red filter 37R transmits red band light (R light) out of the broadband light BB.

  The color filters 37B, 37G, and 37R are repeatedly inserted in a predetermined order (for example, blue, green, red, blue,...) Into the optical path of the broadband light BB as the UOF turret 31 rotates in the normal observation mode. Is done. Thereby, B light, G light, R light, B light,... Are emitted in order from the UOF turret 31.

  As shown in FIG. 4, the LPF turret 32 includes semicircular first LPFs 38a and second LPFs 38b provided along the circumferential direction of the rotation shaft 32a. The first to second LPFs 38a and 38b pass light having a wavelength equal to or greater than a predetermined lower limit wavelength among the incident broadband light BB.

  As shown in FIG. 5, the lower limit wavelength λm1 of the first LPF 38a is set to a value lower than the lower limit wavelength λm2 of the second LPF 38b. The first to second LPFs 38 a and 38 b are selectively inserted into the optical path of the broadband light BB in the special light observation mode by the rotation of the LPF turret 32.

  As shown in FIG. 6, the SPF turret 33 includes first and second semicircular SPFs 39a and 39b provided along the circumferential direction of the rotation shaft 33a. The first to second SPFs 39a and 39b pass light having a wavelength equal to or shorter than a predetermined upper limit wavelength among the incident broadband light BB.

  As shown in FIG. 7, the upper limit wavelength λu1 of the first SPF 39a is set to a value lower than the lower limit wavelength λu2 of the second SPF 39b. The upper limit wavelength λu1 is set to a value higher than the lower limit wavelength λm2 of the second LPF 38b. The first to second SPFs 39a and 39b are selectively inserted into the optical path of the broadband light BB in the special light observation mode by the rotation of the SPF turret 33.

Returning to FIG. 2, when any one of the first to second LPFs 38a and 38b and any one of the first to second SPFs 39a and 39b are respectively inserted into the optical path of the broadband light BB, the wavelength band is limited to a specific wavelength band of blue. Blue narrow band light is generated. The combination of LPF / SPF inserted in the optical path is the following first to fourth insertion patterns, and four types of blue narrow band lights Bn1 to Bn4 having different half widths and center wavelengths are generated for each of the insertion patterns. The The first to fourth insertion patterns are selected in the first to fourth distance observation modes, respectively.
(1) First insertion pattern: second LPF 38b, first SPF 39a
(2) Second insertion pattern: second LPF 38b, second SPF 39b
(3) Third insertion pattern: first LPF 38a, first SPF 39a
(4) Fourth insertion pattern: first LPF 38a, second SPF 39b

  In the first insertion pattern, as shown in FIG. 8A, first, light in the wavelength band of the lower limit wavelength λm2 or more out of the broadband light BB passes through the second LPF 38b. Next, as shown in FIG. 8B, out of the light transmitted through the second LPF 38b, light in the wavelength band of the upper limit wavelength λu1 or less passes through the first SPF 39a. As a result, as shown in FIG. 8C, blue narrow-band light Bn1 having a wavelength band of λm2 to λu1 and a center wavelength of λc1 is generated. In this embodiment, the waveform of the blue narrowband light Bn1 (same for Bn2 to Bn4) is rectangular in order to prevent the drawing from becoming complicated, and the half-value width h1 is “λu1−λm2”. The half value width here is a wavelength band of a portion where the peak value of the light amount is halved.

  In the second insertion pattern, as shown in FIGS. 9A and 9B, the broadband light BB passes through the second LPF 38b and the second SPF 39b in order, so that the wavelength band as shown in FIG. 9C becomes λm2. Blue narrow-band light Bn2 that is approximately λu2 is generated. The full width at half maximum h2 of the blue narrow band light Bn2 is “λu2−λm2”, and the center wavelength is λc2.

  In the third insertion pattern, as shown in FIGS. 10A and 10B, the broadband light BB passes through the first LPF 38a and the first SPF 39a in order, so that the wavelength band as shown in FIG. Blue narrow-band light Bn3 that is approximately λu1 is generated. The half-width h2 of the blue narrow band light Bn3 is “λu1−λm1”, and the center wavelength is λc3.

  In the fourth insertion pattern, as shown in FIGS. 11A and 11B, the broadband light BB passes through the first LPF 38a and the second SPF 39b in order, so that the wavelength band as shown in FIG. 11C becomes λm1. Blue narrow-band light Bn4 that is approximately λu2 is generated. The half-width h4 of the blue narrow band light Bn3 is “λu2−λm1”, and the center wavelength is λc4.

  The wavelength band of each of the blue narrowband lights Bn1 to Bn4 is adjusted in accordance with the short wavelength side peak (for example, around 415 nm) of the two absorption peaks of the light absorption spectrum of hemoglobin. Moreover, since each blue narrowband light Bn1-Bn4 becomes h1 <h2 <h3 <h4, when each light quantity is compared, it will become Bn1 <Bn2 <Bn3 <Bn4. Further, the center wavelengths λc1 to λc4 of the blue narrowband lights Bn1 to Bn4 are also different from each other.

  The blue narrow-band light Bn1 to Bn4 irradiated to the living tissue is very strongly absorbed by blood (hemoglobin) in the surface blood vessel in the living tissue. On the other hand, in the living tissue around the surface blood vessel, most of the irradiated light is reflected by the relatively strong scattering characteristic and returns to the insertion portion distal end portion 16a. As a result, the contrast between the superficial blood vessel and the surrounding biological tissue becomes extremely high, so that the superficial blood vessel and the like can be sufficiently highlighted. As the wavelength band (half-value width) is expanded, the possibility that the blue narrow-band light irradiated to the surface blood vessels returns to the insertion portion distal end portion 16a by reflection or scattering increases. In this case, the amount of light increases while the contrast decreases.

  Returning to FIG. 2, the turret shift mechanism 34 moves the UOF turret 31, the LPF turret 32, and the SPF turret 33 in directions substantially perpendicular to the optical path of the broadband light BB. The turret shift mechanism 34 moves the UOF turret 31 into the position where any one of the color filters 37B, 37G, 37R is inserted into the optical path of the broadband light BB, and the all color filters 37B, 37G, 37R are retracted from the optical path. Move between the retracted position. The turret shift mechanism 34 moves the UOF turret 31 to the insertion position in the normal observation mode, and moves the UOF turret 31 to the retracted position in the special light observation mode.

  Further, the turret shift mechanism 34 includes an insertion position at which the LPF turret 32 and the SPF turret 33 (hereinafter simply referred to as LPF / SPF turrets 32 and 33) are inserted into the optical path of the broadband light BB, and all the filters are in the optical path. It moves between the retracted position retracted from. The turret shift mechanism 34 moves the LPF / SPF turrets 32 and 33 to the retracted position in the normal observation mode, and moves to the insertion position in the special light observation mode.

  The turret rotation mechanism 35 is connected to the rotation shafts 31 a, 32 a, and 33 a of the UOF turret 31, the LPF turret 32, and the SPF turret 33. The turret rotation mechanism 35 rotates the UOF turret 31 at a constant speed in the normal observation mode. The rotation speed of the UOF turret 31 is set so as to rotate once in an imaging period of, for example, 3 frames.

  On the other hand, in the turret rotation mechanism 35 in the special light observation mode, LPF / SPF is inserted with the first insertion pattern in the first distance observation mode, and LPF / SPF is inserted with the second insertion pattern in the second distance observation mode. In the third distance observation mode, the LPF / SPF turrets 32 and 33 are rotated so that the LPF / SPF is inserted in the third insertion pattern, and in the fourth distance observation mode, the LPF / SPF is inserted in the fourth insertion pattern. Let

  The condenser lens 36 is an optical path of B light, G light, and R light emitted from the UOF turret 31 in the normal observation mode, and is a blue narrow band emitted from the LPF / SPF turrets 32 and 33 in the special light observation mode. It arrange | positions on the optical path of light Bn1-Bn4. The condenser lens 36 causes each incident illumination light to enter the light guide 41.

  With each configuration described above, the light source device 13 repeatedly emits B light, G light, and R light to the light guide 41 in the normal observation mode. In the special light observation mode, the light source device 13 emits the blue narrow band lights Bn1 to Bn4 to the light guide 41 according to each sub observation mode.

  The electronic endoscope 11 includes a light guide 41, a CCD type image sensor (hereinafter referred to as “CCD” imaging unit) 44, an analog processing circuit (AFE: Analog Front End) 45, and an imaging control unit 46. The light guide 41 is a large-diameter optical fiber, a bundle fiber, or the like. The light guide 41 has an incident end inserted into the light source device 13 and an emission end opposed to an irradiation lens 48 provided in the insertion portion distal end portion 16a. The illumination light incident on the irradiation lens 48 from the light guide 41 is irradiated into the tube through the illumination window 20. Then, the light reflected in the tube enters the condenser lens 51 through the observation window 19.

  The CCD 44 has an imaging surface 44 a in which a plurality of photodiodes (not shown) are two-dimensionally arranged. The CCD 44 converts subject light incident from the condenser lens 51 into an electrical imaging signal and outputs it to the AFE 45. . The CCD 44 is a monochrome CCD having a predetermined spectral sensitivity. A MOS type image sensor may be used instead of the CCD. An imaging control unit 46 controlled by the processor device 12 is connected to the CCD 44.

  The imaging control unit 46 is connected to a CPU in the processor device 12 and sends a drive signal to the CCD 44 based on a command from the CPU. The CCD 44 outputs an imaging signal to the AFE 45 at a predetermined frame rate based on the drive signal from the imaging control unit 46. In the normal observation mode, in accordance with the rotation of the UOF turret 31, a step of outputting a blue image signal by storing, reading, and transferring signal charges by photoelectric conversion of B light, and accumulation and reading of signal charges by photoelectric conversion of G light A step of outputting a green image signal by transfer and a step of outputting a red image signal by accumulation / reading / transfer of signal charges by photoelectric conversion of R light are repeatedly executed.

  In the special light observation mode, the first to fourth blue narrow-band imaging signals are output to the AFE 45 by storing, reading, and transferring signal charges by photoelectric conversion of any of the blue narrow-band lights Bn1 to Bn4.

  Although not shown, the AFE 45 includes a correlated double sampling circuit (CDS), an automatic gain control circuit (AGC), and an analog / digital converter (A / D). The CDS performs correlated double sampling processing on the imaging signal from the CCD 44 to remove noise. The AGC amplifies the imaging signal from which noise has been removed by CDS. The A / D converts the image pickup signal amplified by the AGC into a digital image pickup signal having a predetermined number of bits and sends it to the processor device 12.

  The processor device 12 includes a memory 53, a CPU (insertion control means) 54, a digital signal processor (DSP) 55, a frame memory 56, a distance determination unit 57, a display control circuit 58, an observation And a mode switch 59. The memory 53 stores a data table 61 in addition to various programs and data for controlling the endoscope system 10.

  The CPU 54 is connected to each part of the processor device 12, the imaging control unit 46 of the electronic endoscope 11, the turret shift mechanism 34 and the turret rotation mechanism 35 of the light source device 13 through signal lines. Based on the data, control them centrally.

  The DSP 55 performs signal processing such as white balance adjustment, color tone processing, gradation processing, and sharpness processing on the imaging signal input from the AFE 45. In the normal observation mode, the DSP 55 sequentially generates normal image data of three colors B, G, and R by performing the above signal processing on the blue imaging signal, the green imaging signal, and the red imaging signal sequentially input from the AFE 45. . These normal image data are sequentially stored in the frame memory 56.

  On the other hand, in the special light observation mode, the DSP 55 performs special signal processing on the first to fourth blue narrow-band imaging signals respectively input from the AFE 45 according to each sub observation mode, so that the special light image data is obtained. Generate. This special light image data is also stored in the frame memory 56.

  The distance determination unit 57 operates in the special light observation mode. The distance discriminating unit 57 detects the exposure amount based on the luminance signal of the special light image data newly stored in the frame memory 56, and based on the exposure amount detection result, the distance between the insertion portion distal end portion 16a and the site to be observed. The distance d is determined. The color of the mucosal surface layer, which is the observed site in the gastrointestinal tract and trachea, does not differ greatly except in special cases such as the occurrence of lesions. For this reason, if the amount of each illumination light emitted from the light source device 13 is constant, the exposure amount decreases as the distance d increases, and conversely, the exposure amount increases as the distance d decreases. Accordingly, the distance d can be obtained from the exposure amount by preparing in advance a data table or the like indicating the relationship between the distance d and the exposure amount for each type of illumination light.

  When the observation mode is the normal observation mode, the display control circuit 58 sequentially reads the three color normal image data from the frame memory 56 and displays the observation image obtained by synthesizing the three color normal images on the monitor 14. Further, when the observation mode is the special light observation mode, the display control circuit 58 reads the special light image data from the frame memory 56 and displays the observation image on the monitor 14 based on the special light image data.

  The observation mode switch 59 is operated when switching the observation mode of the endoscope system 10 to the normal observation mode or the special light observation mode.

  As shown in FIG. 12, the data table 61 stores the range of the distance d in association with each sub observation mode and each insertion pattern under the special observation mode. In the present embodiment, the range of the distance d is divided into four ranges of d <L1, L1 ≦ d <L2, L2 ≦ d <L3, and d ≧ L3, and each sub-observation mode and each of the sub-observation modes and the ranges are sequentially started from the range of the smallest distance d. The insertion pattern is associated. Thereby, the CPU 54 can determine the type of the sub observation mode and the type of the insertion pattern from the distance d by referring to the data table 61.

  The CPU 54 sets the observation mode to the normal observation mode when the observation mode changeover switch 59 is selected, and sets the observation mode to the special light observation mode when the special light observation mode is selected. To do. Further, when the special light observation mode is set, the CPU 54 determines the sub-observation mode based on the determination result of the distance determination unit 57. Then, the CPU 54 controls the turret rotation mechanism 35 according to the insertion pattern corresponding to the sub observation mode, and switches the type of blue narrow band light emitted from the light source device 13.

  Next, the operation of the endoscope system 10 having the above configuration will be described with reference to the flowchart shown in FIG. When the power of the processor device 12 and the light source device 13 is turned on and an endoscopic inspection preparation process (hereinafter referred to as an inspection preparation process) is performed, driving of the CCD 44 is started and broadband light from the broadband light source 30 is started. BB emission is started. The endoscope system 10 is set to the normal observation mode in the initial state when the power is turned on.

  The CPU 54 controls the turret shift mechanism 34 during the inspection preparation process to move the UOF turret 31 to the insertion position and move the LPF / SPF turrets 32 and 33 to the retracted position. Next, the CPU 54 controls the turret rotation mechanism 35 to rotate the UOF turret 31 at a constant speed. Thereby, B light, G light, and R light are repeatedly emitted from the UOF turret 31 toward the condenser lens 36.

  When the examination preparation process is completed, the insertion portion 16 of the electronic endoscope 11 is inserted into a patient's digestive tract, trachea, or other tube. The B light, G light, and R light sequentially incident on the condenser lens 36 are sequentially irradiated into the patient's tube through the light guide 41, the irradiation lens 48, and the illumination window 20, respectively. As a result, the B light, G light, and R light reflected / scattered in the tube are sequentially incident on the observation window 19 and further incident on the CCD 44 through the condenser lens 51. The CCD 44 sequentially photoelectrically converts the B light, G light, and R light, and sequentially outputs a blue image signal, a green image signal, and a red image signal to the AFE 45.

  The AFE 45 performs various signal processing on the image pickup signal from the CCD 44 and sequentially outputs a digital blue image pickup signal, a green image pickup signal, and a red image pickup signal to the DSP 55 of the processor device 12. Each color image signal is subjected to various signal processing by the DSP 55 and then sequentially stored in the frame memory 56 as three-color normal image data. The display control circuit 58 reads each normal image data newly stored in the frame memory 56 and causes the monitor 14 to display an observation image based on each normal image data.

  Hereinafter, until the observation mode is switched to the special light observation mode, or until the endoscopic examination is completed, the acquisition of the normal image data and the monitor display of the normal image are repeatedly executed.

  When switching from normal observation to special light observation, the observation mode switch 59 is switched to the special light observation mode. In the special light observation mode, for example, the first distance observation mode is set in the initial state. The CPU 54 issues a turret switching command to the turret shift mechanism 34 and then issues a first insertion pattern switching command to the turret rotation mechanism 35.

  Upon receiving a turret switching command from the CPU 54, the turret shift mechanism 34 moves the UOF turret 31 to the retracted position and moves the LPF / SPF turrets 32 and 33 to the insertion position. Next, the turret rotation mechanism 35 receives the first insertion pattern switching command from the CPU 54, stops the rotation of the UOF turret 31, and the LPF so that the second LPF 38b and the first SPF 39a are inserted into the optical path of the broadband light BB. / SPF turrets 32 and 33 are rotated. Accordingly, as shown in FIG. 8, the broadband light BB passes through the second LPF 38b and the first SPF 39a in order, so that the blue narrow-band light Bn1 enters the condenser lens 36.

  The blue narrow band light Bn1 is irradiated into the patient's tube through the light guide 41 and the like. Thereby, the blue narrow-band light Bn1 reflected / scattered in the tube enters the CCD 44 through the observation window 19 or the like. The CCD 44 photoelectrically converts the blue narrow band light Bn1 and outputs a first blue narrow band imaging signal to the AFE 45. As a result, the digital first blue narrow-band imaging signal is sent from the AFE 45 to the DSP 55, and special light image data is generated by the DSP 55 and stored in the frame memory 56. Then, the display control circuit 58 reads the special light image data newly stored in the frame memory 56 and causes the monitor 14 to display an observation image based on the special light image data.

  Further, when new special light image data is stored in the frame memory 56, the distance determination unit 57 detects the exposure amount based on the luminance signal of the special light image data, and further inserts it based on the exposure amount detection result. The distance d between the distal end portion 16a and the site to be observed is determined. The distance determination unit 57 sends the determination result of the distance d to the CPU 54.

  The CPU 54 receives the distance determination result from the distance determination unit 57 and refers to the data table 61 in the memory 53. Then, the CPU 54 continues the first distance observation mode when the distance d satisfies d <L1. Hereinafter, until the sub-observation mode is changed or the special light observation is completed, acquisition of special light image data under the irradiation of the blue narrow band light Bn1, display of the observation image, determination of the distance d, and data table 61 references are repeatedly executed.

  Conversely, when the distance d determined by the distance determining unit 57 satisfies L1 ≦ d <L2, or when L2 ≦ d <L3, or when d ≧ L3, the CPU 54 sets the sub-observation mode respectively. Switch to the 2nd to 4th distance observation mode. Specifically, the CPU 54 issues a second insertion pattern switching command to a fourth insertion pattern switching command to the turret rotation mechanism 35 for each of the second to fourth distance observation modes.

  When the turret rotation mechanism 35 receives the second insertion pattern switching command, the turret rotation mechanism 35 rotates the LPF / SPF turrets 32 and 33 so that the second LPF 38b and the second SPF 39b are inserted into the optical path of the broadband light BB. Similarly, when the turret rotation mechanism 35 receives the third to fourth insertion pattern switching commands, the first LPF 38a and the first SPF 39a, and the first LPF 38a and the second SPF 39b are respectively inserted into the optical paths of the broadband light BB. Thereby, blue narrow-band light Bn2-Bn4 is each irradiated in a patient's pipe | tube at the time of the 2nd-4th distance observation mode.

  The blue narrow band lights Bn2 to Bn4 reflected / scattered in the patient's tube in each sub observation mode are incident on the CCD 44. Thereafter, as in the first distance observation mode, photoelectric conversion by the CCD 44, signal processing by the AFE 45 and DSP 55, and the like are sequentially performed, and the special light image data is stored in the frame memory 56. An observation image is displayed on the monitor 14 based on the special light image data, and the distance d is determined by the distance determining unit 57.

  The CPU 54 refers to the data table 61 based on the determination result of the distance d by the distance determination unit 57, and when the current sub-observation mode is continued, acquires the special light image data, displays the observation image, The determination of the distance d and the reference to the data table 61 are repeatedly executed. Conversely, when switching to another sub-observation mode, the CPU 54 controls the turret rotation mechanism 35 to switch the insertion pattern, thereby changing the types of blue narrow-band lights Bn1 to Bn4 emitted from the light source device 13. Switch.

  Hereinafter, the blue narrow band lights Bn1 to Bn4 emitted from the light source device 13 are switched based on the magnitude of the distance d determined by the distance determination unit 57 until the special light observation is completed. As the distance d increases, the light emitted from the light source device 13 is switched in the order of blue narrowband light Bn1, blue narrowband light Bn2, blue narrowband light Bn3, and blue narrowband light Bn4. Conversely, as the distance d becomes shorter, the light emitted from the light source device 13 is switched in the order of blue narrowband light Bn4, blue narrowband light Bn3, blue narrowband light Bn2, and blue narrowband light Bn1.

  Thus, as the distance d becomes longer, the half-value width of the blue narrow band light emitted from the light source device 13 increases, so that the amount of blue narrow band light irradiated into the patient's tube increases. As a result, it is possible to prevent the entire screen from becoming dark due to a lack of light amount during distant view observation. Further, as the distance d becomes shorter, the half-value width of the blue narrow band light emitted from the light source device 13 becomes narrower, so that the amount of blue narrow band light irradiated into the patient's tube decreases. As a result, it is possible to prevent the observation image from becoming too bright during near-field observation. As a result, a good observation image can be obtained regardless of the size of the distance d, such as foreground observation or distant view observation.

  In the first embodiment, blue narrowband light has been described as an example of narrowband light for special light observation. However, for example, narrowband light of each color such as green narrowband light and red narrowband light is emitted. May be.

[Second Embodiment]
Next, an endoscope system according to a second embodiment of the present invention will be described. In the first embodiment, the direction (short wavelength side or long wavelength side) in which the half width of blue narrow band light is expanded is not particularly limited, but in the second embodiment, the direction in which the half width is expanded is limited to the short wavelength side. .

  Note that the endoscope system of the second embodiment is provided with an LPF turret 65 (see FIG. 14) and an SPF 66 (see FIG. 16) that are different from the endoscope system 10 of the first embodiment. The configuration is basically the same as that of the first embodiment. Accordingly, the same functions and configurations as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 14, the LPF turret 65 is inserted into the optical path of the broadband light BB by the turret shift mechanism 34 in the special light observation mode. The LPF turret 65 includes semicircular first LPF 68a and second LPF 68b provided along the circumferential direction of the rotation shaft 65a. The first to second LPFs 68a and 68b are selectively inserted into the optical path of the broadband light BB as the turret rotation mechanism 35 rotates the LPF turret 65.

  As shown in FIG. 15, the first to second LPFs 68a and 68b allow light having a wavelength equal to or greater than the common lower limit wavelength λmx to pass. The lower limit wavelength λmx is, for example, a value near the wavelength of 400 nm. The transmittance of the first LPF 68a gradually increases from the vicinity of the wavelength of 400 nm, and the transmittance rapidly increases to the maximum value when approaching the vicinity of the wavelength of 460 nm. On the other hand, the transmittance of the second LPF 68b is increased to a substantially maximum value near the lower limit wavelength λmx.

  As shown in FIG. 16, the SPF 66 is inserted into the optical path of the broadband light BB by the turret shift mechanism 34 in the special light observation mode. In the second embodiment, the direction in which the half-value width of blue narrow band light is expanded is limited to the short wavelength side, so there is only one type of SPF.

  As shown in FIG. 17, the SPF 66 allows light having a wavelength equal to or shorter than the upper limit wavelength λmy to pass. The upper limit wavelength λmy is a value near the wavelength of 470 nm, for example.

In the special light observation mode, one of the first to second LPFs 68a and 68b is selectively inserted into the optical path of the broadband light BB, while the SPF 66 is always inserted into the optical path. For this reason, each LPF / SPF combination inserted into the optical path of the broadband light BB becomes the following first to second insertion patterns, and two types of blue narrowband light Bnα having different half-value widths for each of the insertion patterns. Bnβ is generated.
(1) First insertion pattern: first LPF 68a, SPF 66
(2) Second insertion pattern: second LPF 68b, SPF 66

  As shown in FIGS. 18A and 18B, in the first insertion pattern, the broadband light BB sequentially passes through the first LPF 68a and the SPF 66, so that the half width as shown in FIG. The blue narrow band light Bnα is generated. In the figure, the interval between wavelengths of 460 nm to 470 nm is shown larger than the actual one (the same applies to FIG. 19C).

  The blue narrow-band light Bnα reaches its peak value when the wavelength is around 460 nm, and when it exceeds 470 nm, the amount of light sharply decreases to almost “0”. On the other hand, on the shorter wavelength side than near 460 nm, the amount of light decreases from near 460 nm to near 400 nm, but the light amount becomes “0” when it falls below near 400 nm, although it is not as sharp as the decrease in the light amount on the long wavelength side. .

  As shown in FIGS. 19A and 19B, in the first insertion pattern, the broadband light BB passes through the second LPF 68b and the SPF 66 in order, so that the half width as shown in FIG. The blue narrow-band light Bnβ is generated. Similar to the blue narrow-band light Bnα, the blue narrow-band light Bnβ sharply decreases on the longer wavelength side than the vicinity of 470 nm where the light quantity reaches the peak value. On the contrary, on the shorter wavelength side than the vicinity of 460 nm, unlike the blue narrow band light Bnα, a high amount of light is maintained between the vicinity of 460 nm and the vicinity of 400 nm. Then, at a point below 400 nm, the light amount starts to decrease rapidly and becomes “0”.

  Further, the upper limit wavelength of the half width hβ is substantially the same as the upper limit wavelength of the half width hα, whereas the lower limit wavelength of the half width hβ is smaller than the lower limit wavelength of the half width hα. Accordingly, the blue narrow band light Bnβ is light obtained by increasing the light amount on the short wavelength side without substantially changing the light amount on the long wavelength side with respect to the blue narrow band light Bnα.

  The reason why the amount of light on the short wavelength side of the blue narrow-band light Bnβ is increased in this way is as follows. Due to the known absorption characteristics of hemoglobin, light with a wavelength lower than about 460 nm of the irradiated light is very strongly absorbed by blood (hemoglobin) in the superficial blood vessel in the living tissue, but conversely exceeds about 460 nm. Light is transmitted as it is with little absorption by hemoglobin. In addition, from the knowledge about the light scattering characteristics of biological tissue (for example, see FIG. 10 of Patent Document 1), most of the irradiated light is absorbed by the surface blood vessels unless the wavelength of the irradiated light exceeds 470 nm. Thus, the insertion portion does not return to the distal end portion 16a. For this reason, by expanding the half-value width of the blue narrow-band light Bnβ to the short wavelength side, it is possible to suppress a decrease in contrast between the superficial blood vessel and the surrounding living tissue, thereby achieving both superficial blood vessel highlighting and an increase in the amount of light. Can be made.

  As shown in FIG. 20, in the endoscope system of the second embodiment, a data table 70 different from that of the first embodiment is stored in the memory 53. In the data table 70, the range of the distance d, two types of sub-observation modes under the special observation mode (near view observation mode, distant view observation mode), and each insertion pattern are stored in association with each other. In the present embodiment, when the distance d is d <L2, the foreground observation mode and the first insertion pattern are used, and conversely, when d ≧ L2, the distant view observation mode and the second insertion pattern are set.

  Hereinafter, as in the first embodiment, the CPU 54 refers to the data table 70 to determine the type of sub observation mode and the type of insertion pattern from the distance d determined by the distance determination unit 57. As a result, the first LPF 68a and the SPF 66 are inserted into the optical path of the broadband light BB during near-field observation, whereby the blue narrow-band light Bnα with a small amount of light is emitted from the light source device 13. Further, during the distant view observation, the second LPF 68b and the SPF 66 are inserted into the optical path of the broadband light BB, so that the light source device 13 emits the blue narrow band light Bnβ with a large amount of light. As a result, as in the first embodiment, a good observation image can be obtained regardless of the distance d, such as foreground observation or distant view observation.

  In the second embodiment, the direction in which the half bandwidth of the narrowband light is expanded according to the distance d is limited to the short wavelength side, but conversely, a combination of one type of LPF and a plurality of types of SPFs is used. By changing, the direction in which the half-value width of the narrow band light is expanded may be limited to the long wavelength side.

[Third Embodiment]
Next, an endoscope system 75 according to a third embodiment of the present invention will be described with reference to FIG. In the endoscope system 10 of the first embodiment, the case where blue narrow band light is emitted from the light source device 13 in the special light observation mode has been described. However, in the endoscope system 75, in addition to the blue narrow band light, the green narrow band light is emitted. Band light is also emitted.

  The endoscope system 75 includes the same electronic endoscope 11 as in the first embodiment, a light source device 76, and a processor device 77. In the third embodiment, the same reference numerals are given to the same functions and configurations as those in the first embodiment, and the description thereof is omitted.

  The light source device 76 has basically the same configuration as the light source device 76 of the first embodiment except that the light source device 76 includes an LFP turret 79, an SPF turret 80, and a turret rotation mechanism 81 that are different from the first embodiment. The LFP turret 79, the SPF turret 80, and the turret rotation mechanism 81 correspond to the filter insertion means of the present invention.

  As shown in FIG. 22, the LFP turret 79 includes a first blue (B) LPF 81 a and a second BLPF 81 b (first long pass filter) that are provided along the circumferential direction of the rotation shaft 79 a, and a quarter circle. A first green (G) LPF 82a and a second GLPF 82b (second long pass filter) are provided. The first to second BLPFs 81a and 81b have the same light transmission characteristics as the first to second LPFs 38a and 38b of the first embodiment, respectively.

  The first to second GLPFs 82a and 82b pass light having a wavelength equal to or greater than a predetermined lower limit wavelength among the incident broadband light BB. The lower limit wavelength λgm1 (see FIG. 26) of the first GLPF 82a is set to a value lower than the lower limit wavelength λgm2 (see FIG. 25) of the second LPF 38b.

  As shown in FIG. 23, the SFP turret 80 includes a first semicircular first BSPF 84a and a second BSPF 84b (first short pass filter) provided along the circumferential direction of the rotation shaft 80a, and a first semicircular first GSPF 85a. And a second GSPF 85b (second short pass filter). The first to second BSPFs 84a and 84b have the same light transmission characteristics as the first to second SPFs 39a and 39b of the first embodiment, respectively.

  1st-2nd GSPF85a, 85b allows the light which has a wavelength below predetermined upper limit wavelength among the incident broadband light BB. The upper limit wavelength λgu1 (see FIG. 25) of the first GSPF 85a is set to a value lower than the upper limit wavelength λgu2 (see FIG. 26) of the second LPF 85b. The upper limit wavelength λgu1 is set to a value higher than the lower limit wavelength λgm2 of the second GLPF 82b.

  Returning to FIG. 21, the first to second BLPFs 81 a and 81 b and the first to second BSPFs 84 a and 84 b follow the first to fourth B insertion patterns that are the same as the insertion patterns of the first embodiment in the special light observation mode. Inserted in the optical path. Thereby, blue narrow-band light Bn1-Bn4 is each produced | generated according to each B insertion pattern.

In addition, a combination of any one of the first to second GLPFs 82a and 82b and any one of the first to second GSPFs 85a and 85b is inserted into the optical path of the broadband light BB, so that the green color is limited to a specific wavelength band of green. Narrow band light is generated. The combination of each GLPF / GSPF inserted into the optical path of the broadband light BB is basically the same as that of the first embodiment, and the four types having different half-value widths and center wavelengths for the following first to fourth G insertion patterns are as follows. Green narrow band lights Gn1 to Gn4 are generated. The first to fourth G insertion patterns are selected in the first to fourth distance observation modes, respectively.
(1) First G insertion pattern: second LPF 82b, first SPF 85a
(2) Second G insertion pattern: second LPF 82b, second SPF 85b
(3) Third G insertion pattern: first LPF 82a, first SPF 85a
(4) Fourth G insertion pattern: first LPF 82a, second SPF 85b

  The wavelength band of each of the green narrowband lights Gn1 to Gn4 is adjusted in accordance with the long wavelength side peak (for example, around 540 nm) of the two absorption peaks of the absorption spectrum of hemoglobin light. Moreover, since each green narrow-band light Gn1-Gn4 has a half value width expanded in order of Gn1-Gn4, when each light quantity is compared, it will become Gn1 <Gn2 <Gn3 <Gn4.

  From the knowledge about the light scattering characteristics of biological tissues, the light reaches the middle-deep blood vessels that are deeper than the superficial blood vessels when the wavelength of the irradiated light is between 500 nm and 600 nm, especially between 530 nm and 570 nm. While this light is absorbed by the middle-deep blood vessel, it is reflected and scattered by the living tissue around the middle-deep blood vessel. Accordingly, when the green tissue is irradiated with the green narrow-band light Gn1 to Gn4, the contrast between the mid-deep blood vessel and the surrounding living tissue becomes high, so that the mid-deep blood vessel and the like can be sufficiently highlighted. As the wavelength band (half-value width) is expanded, the contrast between the middle-layer blood vessel and the surrounding biological tissue is reduced, but the amount of light is increased.

  The turret rotation mechanism 81 performs the same operation as the turret rotation mechanism 35 of the first embodiment in the normal observation mode. On the other hand, in the special light observation mode, the turret rotation mechanism 81 includes BLPF / BSPF corresponding to any of the first to fourth B insertion patterns and GLPF / GSPF corresponding to any of the first to fourth G insertion patterns. The LPF / SPF turrets 79 and 80 are rotated so that they are alternately inserted into the optical path of the broadband light BB. Thereby, in the special light observation mode, any one of the blue narrow band lights Bn1 to Bn4 and any one of the green narrow band lights Gn1 to Gn4 are alternately emitted. Note that, for example, an imaging period for one frame is assigned to the emission of both narrowband lights.

  The processor device 77 is fundamental except that a data table 87 different from that in the first embodiment is stored in the memory 53 and a CPU (insertion control means) 88 different from that in the first embodiment is provided. The configuration is the same as that of the processor device 12 of the first embodiment.

  The data table 87 is basically the same as the data table 61 of the first embodiment, and stores the range of the distance d, each sub observation mode, and each insertion pattern in association with each other. However, in the data table 87, the first to fourth B insertion patterns and the first to fourth G insertion patterns are individually associated with the range of the distance d.

  The CPU 88 basically performs the same processing as the CPU 54 of the first embodiment except in the special light observation mode. However, in the special light observation mode, the CPU 88 determines the type of the sub observation mode based on the determination result of the distance determination unit 57, and determines each B insertion pattern and each 4G insertion pattern corresponding to the determination result. The CPU 88 then turns the turret rotation mechanism 81 so that the BLPF / BSPF corresponding to the determined B insertion pattern and the GLPF / GSPF corresponding to the determined G insertion pattern are alternately inserted into the optical path of the broadband light BB. To control.

  In the special light observation mode, since the blue narrow band light and the green narrow band light are alternately emitted, the blue special light image data and the green special light image data are generated and stored in the frame memory 56. The display control circuit 58 displays an observation image on the monitor 14 based on the two-color special light image data read from the frame memory 56. As a result, both the superficial blood vessel and the intermediate deep blood vessel are highlighted.

  Next, the operation of the endoscope system 75 of the third embodiment will be described using the flowchart shown in FIG. The processing until switching to the special light observation mode is the same as that in the first embodiment shown in FIG.

  After switching to the special light observation mode, the CPU 88 determines the sub observation mode to be the first distance observation mode which is the initial state. Next, the CPU 88 controls the turret rotation mechanism 81 to rotate the LPF / SPF turrets 79 and 80 so that the second BLPF 81b and the first BSPF 84a are inserted into the optical path of the broadband light BB. As a result, the blue narrow-band light Bn1 is emitted from the light source device 76, whereby blue special light image data is generated and stored in the frame memory 56.

  The distance determination unit 57 determines the distance d based on the blue special light image data newly stored in the frame memory 56. In this case, for example, a data table in which the relationship between the exposure amount under blue narrow-band light and the distance d is obtained in advance is used. For example, when the determination result of the distance determination unit 57 is “distance d <L1”, the CPU 88 maintains the first distance observation mode and determines the first G insertion pattern as the G insertion pattern.

  Next, the CPU 88 controls the turret rotation mechanism 81 when the emission time of the blue narrowband light Bn1 has passed a predetermined one frame imaging period, so that the second GLPF 82b and the first GSPF 85a are in the optical path of the broadband light BB. The LPF / SPF turrets 79 and 80 are rotated so that they are inserted.

  As shown in FIGS. 25A and 25B, when the broadband light BB passes through the second GLPF 82b and the first GSPF 85a in order, the green narrow band light whose half-value width is hg1 as shown in FIG. 25C. Gn1 is generated, and this green narrowband light Gn1 is emitted from the light source device 76. Thereby, green special light image data is generated and stored in the frame memory 56.

  On the other hand, when the determination result of the distance determination unit 57 changes to “distance d ≧ L3”, the CPU 88 determines the fourth distance observation mode as the sub observation mode and the fourth G insertion pattern as the G insertion pattern. To decide. In this case, the CPU 88 controls the turret rotation mechanism 81 to rotate the LPF / SPF turrets 79 and 80 so that the first GLPF 82a and the second GSPF 85b are inserted into the optical path of the broadband light BB.

  As shown in FIGS. 26A and 26B, when the broadband light BB passes through the second GLPF 82b and the first GSPF 85a in order, the half-value width shown in FIG. 26C becomes hg4 (> hg1). Green narrowband light Gn4 is generated, and this green narrowband light Gn4 is emitted from the light source device 76. Thereby, green special light image data is generated and stored in the frame memory 56.

  The distance determination unit 57 determines the distance d based on the green special light image data newly stored in the frame memory 56. In this case, for example, a data table in which the relationship between the exposure amount under green narrow band light and the distance d is obtained in advance is used. Then, the CPU 88 determines the sub observation mode and the B insertion pattern based on the determination result of the distance determination unit 57, and controls the turret rotation mechanism 81 to rotate the LPF / SPF turrets 79 and 80 based on the B insertion pattern. . Thereby, the blue narrow band light corresponding to the sub-observation mode among the blue narrow band lights Bn1 to Bn4 is emitted from the light source device 76.

  Similarly, one of the green narrowband lights Gn1 to Gn4 and one of the blue narrowband lights Bn1 to Bn4 are alternately and repeatedly emitted from the light source device 76 based on the determination result of the distance determination unit 57. Also in the third embodiment, as the distance d becomes longer, the half-value widths of the blue narrow-band light and the green narrow-band light emitted from the light source device 76 are expanded. Will increase. Conversely, as the distance d becomes shorter, the half-value widths of the blue narrow-band light and the green narrow-band light emitted from the light source device 76 become narrower. Decrease. As a result, as in the first embodiment, a good observation image can be obtained regardless of the distance d, such as foreground observation or distant view observation.

  In the third embodiment, the distance d is determined each time the blue special light image data and the green special light image data are stored in the frame memory 56. For example, either one of the two special light image data is determined. The distance d may be determined only when is stored in the frame memory 56.

  In the third embodiment, the full width at half maximum of both the blue narrow band light and the green narrow band light is expanded as the distance d increases. However, only the half width of either one of the narrow band lights is expanded. May be.

  In the third embodiment, two types of narrowband light, that is, blue narrowband light and green narrowband light, are emitted. Three or more colors of narrowband light may be emitted.

  In the third embodiment, an explanation has been given by taking as an example an endoscope system of a so-called frame sequential irradiation method that alternately emits two types of narrowband light of blue narrowband light and green narrowband light. The present invention can also be applied to a mixed simultaneous irradiation type endoscope system that simultaneously irradiates a plurality of types of illumination light and simultaneously images a plurality of types of illumination light with a color image sensor.

  In the first and third embodiments, four types of first to fourth distance observation modes are provided as sub observation modes according to the size of the distance d. However, the number of filters of the LPF turret and the SPF turret is increased. Four or more types of distance observation modes may be provided. Similarly, in the second embodiment, two or more types of distance observation modes may be provided.

  In the first to third embodiments, each unit of the light source device is controlled by the CPU of the processor device. However, a control unit such as a CPU that controls these units may be provided in the light source device.

  In each of the above embodiments, as the distance d increases, the amount of narrowband light is increased by expanding the half-value width of narrowband light. For example, the amount of light is increased by expanding the wavelength band of narrowband light. It may be increased.

  The distance discriminating unit 57 in each of the above embodiments discriminates the distance d by detecting the exposure amount based on the luminance signal of the special light image data. May be performed.

  In each of the above-described embodiments, the endoscope system that performs special light observation of the surface blood vessel and the middle-deep blood vessel using light of a specific wavelength has been described as an example, but light of a specific wavelength is used. The present invention can be applied to various observations such as fluorescence observation (Auto Fluorescence Imaging), infrared light observation (Infra Red Imaging), photodynamic diagnosis (Photodynamic diagnosis), and endoscope systems used for diagnosis. .

DESCRIPTION OF SYMBOLS 10,75 Endoscope system 11 Electronic endoscope 12,77 Processor unit 13,76 Light source unit 32,65,79 Long pass filter (LPF) turret 33,80 Short pass filter (SPF) turret 35,81 Turret rotation mechanism 38a 68a 1st LPF
38b, 68b 2nd LPF
39a 1st SPF
39b 2nd SPF
54,88 CPU
65 SPF
81a, 81b 1st to 2nd BLPF
82a, 82b 1st to 2nd GLPF
84a, 84b 1st to 2nd BSPF
85a, 85b 1st to 2nd GSPF

Claims (9)

A broadband light source that emits white broadband light; and
A short-pass filter unit one short-pass filter for blue Ru passed through a blue light having a wavelength less than a predetermined upper limit wavelength of said broadband light is formed,
A blue long-pass filter that allows blue light having a wavelength equal to or greater than a predetermined lower limit wavelength to pass among the broadband light, and for at least two types of blue having different ways of increasing transmittance from the lower limit wavelength to the upper limit wavelength side A long pass filter unit formed with a long pass filter;
By inserting a pair of the blue short-pass filter and the blue long-pass filter into the optical path of the broadband light, it is used for special light observation to obtain an observation image in which blood vessels of living tissue are emphasized . Filter insertion means for generating blue narrowband light corresponding to a wavelength band having a large amount of absorption on the short wavelength side of the light absorption spectrum ;
And controls the filter insertion unit is inserted into the optical path by switching a set of the blue short-pass filter combination of the blue long-pass filter, and insertion control means for changing a light amount of the blue narrowband light ,
The endoscope system characterized by comprising an imaging means for capturing an object of interest to the blue narrow-band light is irradiated. The blue narrow-band light endoscope system according to claim 1, wherein the half-width is changed by switching the type of the long-pass filter for blue. The upper limit wavelength before Symbol short-pass filter for blue endoscope system according to claim 1 or 2, characterized in that a value around 470 nm. The endoscope system according to any one of claims 1 to 3, wherein the short pass filter unit and the long pass filter unit are circular turrets having a rotation axis as a center. Based on an imaging signal acquired by imaging of the imaging means, the distance determination means for determining the distance between the distal end portion of the endoscope and the site to be observed,
The insertion control means controls the filter insertion means so that the half-value width of the blue narrowband light increases and the light quantity increases as the distance determined by the distance determination means increases , the endoscope system according to any one of claims 1 to 4, wherein the benzalkonium switching the combination of the blue for short-pass filter and the blue long-pass filter to be inserted. The short-pass filter unit, in addition to the short-pass filter for the blue to generate the blue narrow-band light, green short to produce a green narrow-band light the a longer wavelength than blue narrow-band light It has a Pasufiru data,
The long-pass filter unit, in addition to the blue long-pass filter for generating the blue narrow-band light has a green long-pass filter for generating a green narrow-band light,
The filter insertion means inserts the blue short-pass filter and the blue long-pass filter into the optical path when generating the blue narrowband light,
The green when generating narrow-band light, of according to 5 any one claims 1 to characterized in that inserting the green B ring-pass filter and the green short-pass filter in the light path Endoscopic system. The short pass filter unit has one blue short pass filter and a plurality of green short pass filters having different upper limit wavelengths of the green narrowband light ,
The long-pass filter unit, the lower limit wavelength or al the way of rising of transmittance different from the plurality of blue long-pass filter to the upper wavelength side, and a plurality of the green long pass the lower limit wavelength is different of the green narrow-band light The endoscope system according to claim 6 , further comprising a filter. Based on an imaging signal acquired by imaging of the imaging means, the distance determining means for determining the distance between the distal end portion of the insertion portion of the endoscope and the site to be observed,
The insertion control means controls the filter insertion means so that the half-value widths of the blue narrowband light and the green narrowband light are increased as the distance determined by the distance determination means increases, and 8. The endoscope system according to claim 7, wherein a combination of the short-pass filter and the long-pass filter for green and the green is switched respectively. The endoscope system according to any one of claims 6 to 8, wherein the green narrow-band light is light in a wavelength band having a large amount of absorption on a long wavelength side of the absorption spectrum.

Images