JPWO2015029709A1 - Endoscope system - Google Patents

Abstract

An observation image in which the contrast of the superficial blood vessel is made more conspicuous is obtained, and the superficial blood vessel is observed more finely. A long cut filter (LCF) (48) is provided in front of the blue semiconductor light source 35. The LCF (48) is a reflectance of the superficial blood vessels and the middle blood vessels in the reflection spectrum of the superficial blood vessels existing in the mucosal surface layer of the living tissue and the middle blood vessels existing in the middle layer of the blue light LB emitted from the blue semiconductor light source (35). A long wavelength component longer than the wavelength (450 nm) of the intersection point P is cut to generate long cut blue light LBlc1. The long cut blue light LBlc1, green light LG, and red light LR mixed light is irradiated onto the observation region and imaged by the image sensor (56). The enhancement processing unit (70) performs a process of enhancing the superficial blood vessels on the image signal output from the image sensor (56).

Description

  The present invention relates to an endoscope system.

  In the medical field, endoscopic diagnosis using an endoscopic system is widespread. An endoscope system includes an endoscope, an endoscope light source device that supplies illumination light to the endoscope (hereinafter simply referred to as a light source device), and a processor device that processes an image signal output from the endoscope. It has. The endoscope has an insertion portion that is inserted into a living body. At the distal end of the insertion portion, an illumination window for irradiating the observation site (subject) with illumination light and an observation window for imaging the observation site are arranged. The endoscope has a built-in light guide made of a fiber bundle in which optical fibers are bundled. The light guide guides the illumination light supplied from the light source device to the illumination window. An imaging element such as a CCD is disposed in the back of the observation window. The observation site irradiated with the illumination light is imaged by the imaging device, and an observation image is generated by the processor device based on the image signal output from the imaging device. The observation image is displayed on the monitor, and in vivo observation is performed.

  In recent endoscopic diagnosis, special light limited to a specific wavelength band (narrowband light) is used, compared to conventional observations that grasp the overall properties of the surface of living tissue under white light. The observations used are also actively conducted. There are various types of observation using special light, but using the optical property that the depth of light penetration into the living tissue varies depending on the wavelength, the blood vessels existing in the mucous membrane of the living tissue are highlighted and displayed. Blood vessel enhancement observation is known (see Patent Documents 1 and 2). In abnormal tissues such as cancer that occurs in living tissue, the state of blood vessels is different from that in normal tissues, so that blood vessel enhancement observation has been found useful for early cancer detection.

  In the light source devices described in Patent Documents 1 and 2, in addition to the light source that emits white light, a blue semiconductor that emits narrow-band blue light having a central wavelength of about 445 nm, for example, is well absorbed by the surface blood vessels present on the surface of the mucosa. A light source is provided as a special light source. Each of these light sources is turned on to irradiate the observation site with white light and blue light at the same time, and the reflected light is picked up by the image pickup device, thereby obtaining an observation image in which the surface blood vessels are emphasized. In Patent Documents 1 and 2, in order to obtain an observation image in which the surface blood vessels are more emphasized, a process for enhancing the surface blood vessels is performed on the image signal output from the image sensor.

JP 2011-098088 A JP 2012-152659 A

  By the way, the present inventors have found the relationship between the reflection spectra of the mucous membrane, surface blood vessel, and middle blood vessel shown in FIG. In FIG. 29, the reflection spectrum of the mucous membrane is indicated by a two-dot chain line, the reflection spectrum of the surface layer blood vessel is indicated by a solid line, and the reflection spectrum of the middle layer blood vessel is indicated by a dotted line. Representative examples of superficial blood vessels are blood vessels with a thickness of 10 μm present at a depth of 10 μm from the mucosal surface, and middle blood vessels are blood vessels with a thickness of 10 to 20 μm present at a depth of 50 μm from the mucosal surface. Show.

  The reflectance of the superficial blood vessels is greatly reduced in the wavelength band below 450 nm, and the difference from the reflectance of the middle blood vessels and mucous membranes is large. On the other hand, the reflectance of the middle-layer blood vessels is not as high as that of the surface blood vessels, but decreases in the wavelength band of 530 nm to 560 nm, and the difference from the reflectance of the surface blood vessels and mucous membranes is increased. The reflectance of the mucous membrane is larger than the reflectance of the surface blood vessel and the middle blood vessel in the entire wavelength band.

  Focusing on the change in the reflectance of the superficial blood vessel and the middle blood vessel, the superficial blood vessel has a lower reflectance than the middle blood vessel in the wavelength band below 450 nm, and the reflectance of the superficial blood vessel and the middle blood vessel becomes the same around 450 nm. In the above wavelength band, the reflectivity is reversed, and the middle layer blood vessel has a lower reflectivity than the surface layer blood vessel. In other words, when light in a wavelength band below 450 nm is irradiated, the superficial blood vessel absorbs light better and is emphasized on the observation image. On the other hand, when light in the wavelength band of 450 nm or more is irradiated, the middle blood vessel Is emphasized on the observed image. For this reason, when a surface blood vessel is an observation target, the difference between the surface blood vessel and the middle blood vessel is smaller when the light component in the wavelength band of 450 nm or more, which is the intersection of the reflectance of the surface blood vessel and the middle blood vessel indicated by the symbol P, is smaller. It can be seen that a high-contrast observation image that is clearly distinguished can be obtained.

  However, the blue light having a central wavelength of about 445 nm used as special light in Patent Documents 1 and 2 includes a light component having a wavelength band of 450 nm or more that reduces the contrast of the surface blood vessels on the observation image. Therefore, in Patent Documents 1 and 2, the contrast of the surface blood vessels is improved by image processing, but a high-contrast observation image in which the difference between the surface blood vessels and the middle blood vessels is clearly distinguished is obtained. It was hard to say. Therefore, the middle layer blood vessel may be in the way and the surface layer blood vessel may not be observed precisely.

  The present invention has been made in view of the above problems, and obtains an observation image in which the contrast of the superficial blood vessels is more conspicuous in superficial blood vessel emphasizing observation in which superficial blood vessels existing on the mucous membrane surface layer of a living tissue are emphasized and observed. An object of the present invention is to provide an endoscope system that can observe the superficial blood vessels more precisely.

  In order to achieve the above object, the endoscope system of the present invention includes a blue light source and a long cut filter. The blue light source emits blue light in a blue wavelength band. The long cut filter is provided on the optical path of blue light. Of the blue light, the reflectance of the superficial blood vessels and the middle blood vessels in the reflection spectrum of the superficial blood vessels in the mucosal surface layer of the living tissue and the middle blood vessels in the middle layer is determined. Cut at least a part of the long wavelength component equal to or greater than the wavelength of the intersection.

  The wavelength of the intersection is a value in the range of 445 nm to 460 nm, for example, 450 nm.

  The blue light source is preferably a blue semiconductor light source having a blue semiconductor light emitting element. The blue semiconductor light emitting element is, for example, a blue light emitting diode.

  An optical path that integrates an optical path of each color light emitted from a green semiconductor light source, a red semiconductor light source, and a blue semiconductor light source, a green semiconductor light source that emits green light in the green wavelength band, a red semiconductor light source that emits red light in the red wavelength band It is preferable to have an integration part.

  A green semiconductor light source, a red semiconductor light source, and a blue semiconductor light source emit light of each color at the same time, and the image sensor is a color image sensor having blue, green, and red micro color filters, and outputs blue, green, and red image signals. It is preferable to output.

  Provide a mode switching unit that switches between the superficial blood vessel emphasis observation mode that activates the cut function of the long cut filter and emphasizes superficial blood vessels, and the normal observation mode that invalidates the cut function and observes the observation site Is preferred. The mode switching unit is, for example, a long unit between an operation member that issues an instruction signal for instructing mode switching, a set position that is disposed on the blue light optical path, and a retreat position that is retracted from the blue light optical path. A long cut filter moving mechanism for moving the cut filter; and a control unit for controlling driving of the long cut filter moving mechanism in response to an instruction signal from the operation member.

  The light source device for endoscopes has a purple semiconductor light source that emits purple light in a purple wavelength band for observing a near-surface blood vessel closer to the mucosal surface layer among the surface blood vessels present on the mucosal surface layer of living tissue. You may do it.

  Imaging an observation target illuminated with illumination light including long-cut blue light in which at least a part of a long wavelength component equal to or greater than the wavelength of the intersection is cut, and outputting an image signal, and an image signal, It is preferable to have an enhancement processing unit that performs a process of enhancing the surface blood vessel.

  According to the present invention, among the blue light of the blue wavelength band emitted from the blue light source, the reflectance of the surface blood vessels and the middle layer blood vessels in the reflection spectrum of the surface blood vessels present in the mucosal surface layer of the living tissue and the middle layer blood vessels present in the middle layer. Since at least a part of the long wavelength component equal to or greater than the wavelength of the intersection is cut, it is possible to obtain an observation image in which the contrast of the superficial blood vessels is more conspicuous, and the superficial blood vessels can be observed more precisely.

It is an external view of the endoscope system of the present invention. It is a front view of the front-end | tip part of an endoscope. It is a block diagram which shows the electric constitution of an endoscope system. It is a figure which shows a blue semiconductor light source. It is a graph which shows the emission spectrum of the blue light which a blue semiconductor light source emits. It is a graph which shows the emission spectrum of the green light which a green semiconductor light source emits. It is a graph which shows the emission spectrum of the red light which a red semiconductor light source emits. It is a graph which shows the transmission characteristic of a long cut filter. It is a graph which shows the emission spectrum of long cut blue light. It is a graph which shows the emission spectrum of the illumination light comprised by long cut blue light, green light, and red light. It is a graph which shows the spectral characteristic of the micro color filter of an image sensor. It is explanatory drawing which shows the irradiation timing of illumination light, and the operation timing of an image pick-up element. It is a figure which shows the surface blood vessel and middle layer blood vessel drawn by B image. It is a figure which shows the surface blood vessel and middle-layer blood vessel drawn by G image. It is a figure which shows arrangement | positioning of each semiconductor light source, and the detailed structure of an optical path integration part. It is a graph which shows the transmission characteristic of the dichroic filter of the dichroic mirror which integrates the optical path of green light and red light. It is a graph which shows the transmission characteristic of the dichroic filter of the dichroic mirror which integrates the optical path of blue light, green light, and red light. It is a graph which shows the transmission characteristic of a long cut filter in case the wavelength of the intersection P of the reflectance of a surface blood vessel and a middle blood vessel is 460 nm. It is a graph which shows the emission spectrum of the long cut blue light of the example of FIG. It is a graph which shows the emission spectrum of the illumination light comprised by the long cut blue light of the example of FIG. 18, green light, and red light. It is a figure which shows the light source device of 2nd Embodiment which provided the mode switching part. It is a graph which shows the emission spectrum of the illumination light comprised by blue light, green light, and red light. It is a figure which shows the light source device of 3rd Embodiment which provided the purple semiconductor light source. It is a graph which shows the emission spectrum of the purple light which a purple semiconductor light source emits. It is a graph which shows the emission spectrum of the illumination light comprised by long cut blue light, green light, red light, and purple light. It is a graph which shows the transmission characteristic of the dichroic filter of the dichroic mirror which integrates the optical path of blue light and purple light. It is a graph which shows the scattering coefficient of a biological tissue. It is explanatory drawing which shows the irradiation timing of the illumination light in the emphasis observation of the polar surface blood vessel, and the operation timing of the image sensor. It is a graph which shows the reflection spectrum of a mucous membrane, a surface blood vessel, and a middle-layer blood vessel.

[First embodiment]
In FIG. 1, an endoscope system 10 includes an endoscope 11 that images an observation site in a living body, a processor device 12 that generates an observation image of the observation site based on an image signal obtained by imaging, and an observation site. Is provided with a light source device 13 for supplying illumination light to the endoscope 11 and a monitor 14 for displaying an observation image. An operation input unit 15 such as a keyboard or a mouse is connected to the processor device 12.

  The endoscope 11 connects the insertion portion 16 inserted into the digestive tract of a living body, the operation portion 17 provided at the proximal end portion of the insertion portion 16, the endoscope 11, the processor device 12, and the light source device 13. And a universal cord 18.

  The insertion portion 16 includes a distal end portion 19, a bending portion 20, and a flexible tube portion 21 that are continuously provided from the distal end. As shown in FIG. 2, the distal end surface of the distal end portion 19 is supplied with an illumination window 22 for irradiating the observation site with illumination light, an observation window 23 for capturing an image of the observation site, and air supply for cleaning the observation window 23. An air supply / water supply nozzle 24 for supplying water and a forceps outlet 25 for performing various treatments by projecting a treatment tool such as forceps and an electric knife are provided. In the back of the observation window 23, an image sensor 56 and an objective optical system 60 for image formation (both see FIG. 3) are incorporated.

  The bending portion 20 includes a plurality of connected bending pieces, and is bent in the vertical and horizontal directions by operating the angle knob 26 of the operation portion 17. By bending the bending portion 20, the direction of the distal end portion 19 is directed in a desired direction. The flexible tube portion 21 is flexible so that it can be inserted into a tortuous duct such as the esophagus or the intestine. The insertion unit 16 includes a communication cable that communicates a drive signal for driving the image sensor 56 and an image signal output from the image sensor 56, and a light guide 55 that guides illumination light supplied from the light source device 13 to the illumination window 22. Etc.) are inserted.

  In addition to the amble knob 26, the operation unit 17 includes a forceps port 27 for inserting a treatment instrument, an air / water supply button 28 that is operated when air / water is supplied from the air / water supply nozzle 24, and a still image. A release button (not shown) for photographing is provided.

  A communication cable and a light guide 55 extending from the insertion portion 16 are inserted into the universal cord 18, and a connector 29 is attached to one end of the processor device 12 and the light source device 13. The connector 29 is a composite type connector composed of a communication connector 29a and a light source connector 29b. The communication connector 29a and the light source connector 29b are detachably connected to the processor device 12 and the light source device 13, respectively. One end of a communication cable is disposed on the communication connector 29a, and an incident end 55a (see FIG. 3) of the light guide 55 is disposed on the light source connector 29b.

  In FIG. 3, the light source device 13 includes a light source unit 40 including three semiconductor light sources 35, 36, and 37 of blue, green, and red, and an optical path integration unit that integrates the optical paths of the respective color lights of the semiconductor light sources 35 to 37. 41 and a light source control unit 42 that controls driving of the semiconductor light sources 35 to 37.

  Each of the semiconductor light sources 35 to 37 is, as a semiconductor light emitting element, a blue light emitting diode (LED) 43 that emits light in a blue wavelength band, a green LED 44 that emits light in a green wavelength band, and light in a red wavelength band. Each has a red LED 45 that emits. Each of the LEDs 43 to 45 is formed by joining a P-type semiconductor and an N-type semiconductor as is well known. When a voltage is applied, electrons and holes recombine near the PN junction near the PN junction and a current flows, and energy corresponding to the band gap is emitted as light at the time of recombination. When each LED 43 to 45 increases the value of the supplied power, the amount of emitted light increases.

  As shown in FIG. 4, the blue semiconductor light source 35 includes a substrate 35a on which a blue LED 43 is mounted, a mold 35b formed on the substrate 35a and having a cavity for accommodating the blue LED 43, and a resin sealed in the cavity. 35c. The inner surface of the cavity functions as a reflector that reflects light. A diffusion material for diffusing light is dispersed in the resin 35c. The blue LED 43 is electrically connected to the substrate 35a by the wiring 35d. Such a mounting form of the blue semiconductor light source 35 is generally called a surface mounting type. Since the semiconductor light sources 35 to 37 have basically the same configuration, the blue semiconductor light source 35 will be described as an example, and the description of the green and red semiconductor light sources 36 and 37 will be omitted.

  As shown in FIG. 5, the blue semiconductor light source 35 has, for example, a wavelength component in the vicinity of 440 nm to 470 nm which is a blue wavelength band, and emits blue light LB having a center wavelength of 455 ± 10 nm and a peak wavelength of 455 nm. As shown in FIG. 6, the green semiconductor light source 36 has, for example, a wavelength component in the vicinity of 500 nm to 600 nm, which is a green wavelength band, and emits green light LG having a center wavelength of 520 ± 10 nm and a peak wavelength of 520 nm. Further, as shown in FIG. 7, the red semiconductor light source 37 has, for example, a wavelength component in the vicinity of 615 nm to 635 nm which is a red wavelength band, and emits red light LR having a center wavelength of 620 ± 10 nm and a peak wavelength of 625 nm. The center wavelength indicates the wavelength at the center of the emission spectrum width of each color light, and the peak wavelength indicates the peak of the peak of the emission spectrum of each color light.

  In FIG. 3, a long cut filter (hereinafter abbreviated as LCF) 48 is provided in front of the blue semiconductor light source 35. The LCF 48 is the reflectance of the superficial blood vessels and the middle blood vessels in the reflection spectrum of the superficial blood vessels present in the mucosal surface layer of the biological tissue and the middle blood vessels present in the middle layer of the blue light LB emitted from the blue semiconductor light source 35 as shown in FIG. Long wavelength components longer than the wavelength (450 nm) of the intersection P are cut. More specifically, as shown in FIG. 8, the LCF 48 has a characteristic of reflecting light in the green and red wavelength bands having a wavelength of 450 nm or more and transmitting light in the blue wavelength band of less than that. .

  By the LCF 48, the blue light LB becomes the long cut blue light LBlc1 shown in FIG. The long-cut blue light LBlc1 is light in which all of the light components in the wavelength band of 450 nm or more that hinder the improvement of the contrast of the surface blood vessels described with reference to FIG. 29 are cut out of the blue light LB. The long cut blue light LBlc1 is incident on the optical path integration unit 41.

  In the LCF 48, the wavelength of the intersection point P (to the extent that the contrast improvement of the surface blood vessel can be sufficiently ensured without completely cutting (ie, 100% cut) the long wavelength component longer than the wavelength of the intersection point P (450 nm). 450 nm) or more of the long wavelength component (for example, 80 to 95%) is cut. Thereby, the spectrum of the long cut blue light LBlc1 is not discrete and continuous with the spectrum of the green light LG on the longer wavelength side.

  Drivers 50, 51, and 52 are connected to the LEDs 43 to 45, respectively. The light source control unit 42 controls turning on / off of the LEDs 43 to 45 and the amount of light through the drivers 50 to 52. The amount of light is controlled by changing the power supplied to each of the LEDs 43 to 45 based on the exposure control signal received from the processor device 12.

  Each driver 50-52 lights each LED43-45 by giving a drive current to each LED43-45 continuously under control of the light source control part 42. As shown in FIG. Then, in accordance with the exposure control signal received from the processor device 12, the power supplied to the LEDs 43 to 45 is changed by changing the drive current value to be applied, and the light amounts of the blue light LB, the green light LG, and the red light LR are changed. Control each independently. PAM (Pulse Amplitude Modulation) control that changes the amplitude of the drive current pulse, and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse. May be performed.

  The optical path integration unit 41 integrates the optical paths of the long cut blue light LBlc1, the green light LG, and the red light LR into one optical path. The light emitting part of the optical path integrating part 41 is disposed in the vicinity of the receptacle connector 54 to which the light source connector 29b is connected. The optical path integrating unit 41 emits the light incident from each of the semiconductor light sources 35 to 37 to the incident end 55 a of the light guide 55 of the endoscope 11. Although not shown, each of the light source connector 29b and the receptacle connector 54 is provided with protective glass.

  The emission spectrum of the mixed light of the long cut blue light LBlc1, the green light LG, and the red light LR integrated by the optical path integration unit 41 is shown in FIG. This mixed light is used as illumination light LW1. Note that the emission spectrum of the illumination light LW1 shown in FIG. 10 is an example, and the emission spectrum of the target illumination light LW1 may be variously changed according to the color of the desired observation image. Specifically, the ratio of the light amounts of the long cut blue light LBlc1, green light LG, and red light LR (the ratio of the drive current values of the LEDs 43 to 45) is changed to generate the illumination light LW1 having a target emission spectrum. . Here, as described above, the long cut blue light LBlc1 and the green light LG have continuous spectra, and the green light LG and the red light LR have continuous spectra. The spectrum of the light LW1 is continuous over the entire wavelength band (about 400 to about 670 nm). Therefore, the illumination light LW1 has a color rendering property equivalent to or similar to that of a xenon lamp whose spectrum is continuous over the entire wavelength band.

  The light source controller 42 controls the exposure of illumination light while maintaining the target emission spectrum. When the ratio of the amount of light of each color constituting the illumination light changes, the emission spectrum of the illumination light changes and the color of the observation image changes. For this reason, the light source control part 42 changes the drive current value given to each LED43-45 through each driver 50-52 independently so that the ratio of the light quantity of each color light may become constant, and increases / decreases the light quantity of each color light.

  The endoscope 11 includes a light guide 55, an imaging device 56, an analog processing circuit 57 (AFE: Analog Front End), and an imaging control unit 58. The light guide 55 is a fiber bundle obtained by bundling a plurality of optical fibers. When the light source connector 29 b is connected to the light source device 13, the incident end 55 a of the light guide 55 disposed on the light source connector 29 b faces the light emitting portion of the optical path integrating portion 41. The emission end of the light guide 55 located at the distal end portion 19 branches into two at the front stage of the illumination window 22 so that light is guided to the two illumination windows 22.

  An irradiation lens 59 is disposed in the back of the illumination window 22. The illumination light supplied from the light source device 13 is guided to the irradiation lens 59 by the light guide 55 and irradiated from the illumination window 22 toward the observation site. The irradiation lens 59 is a concave lens, and widens the divergence angle of the light emitted from the light guide 55. Thereby, illumination light can be irradiated to the wide range of an observation site | part.

  In the back of the observation window 23, an objective optical system 60 and an image sensor 56 are arranged. The image of the observation site is incident on the objective optical system 60 through the observation window 23 and is formed on the imaging surface 56 a of the imaging device 56 by the objective optical system 60.

  The imaging element 56 is composed of a CCD image sensor, a CMOS image sensor, or the like, and a plurality of photoelectric conversion elements constituting pixels such as photodiodes are arranged in a matrix on the imaging surface 56a. The imaging element 56 photoelectrically converts the light received by the imaging surface 56a, and accumulates signal charges corresponding to the amount of received light in each pixel. The signal charge is converted into a voltage signal by an amplifier and read out. The voltage signal is output from the image sensor 56 to the AFE 57 as an image signal.

  The AFE (Analog Front End) 57 includes a correlated double sampling circuit, an automatic gain control circuit, and an analog / digital converter (all not shown). The correlated double sampling circuit performs correlated double sampling processing on the analog image signal from the image sensor 56, and removes noise caused by signal charge reset. The automatic gain control circuit amplifies the image signal from which noise has been removed by the correlated double sampling circuit. The analog / digital converter converts the image signal amplified by the automatic gain control circuit into a digital image signal having a gradation value corresponding to a predetermined number of bits and inputs the digital image signal to the processor device 12.

  The imaging control unit 58 is connected to the controller 65 in the processor device 12, and inputs a drive signal to the imaging device 56 in synchronization with a reference clock signal input from the controller 65. The imaging element 56 outputs an image signal to the AFE 57 at a predetermined frame rate based on the drive signal from the imaging control unit 58.

  The image pickup device 56 is a color image pickup device. The image pickup surface 56a is provided with B, G, and R three-color micro color filters having spectral characteristics as shown in FIG. Assigned to. The arrangement of the micro color filters is, for example, a Bayer arrangement.

  The B pixel to which the B filter is assigned is sensitive to light in the wavelength band of about 380 nm to 560 nm, and the G pixel to which the G filter is assigned is sensitive to light in the wavelength band of about 450 nm to 630 nm. The R pixel to which the R filter is assigned is sensitive to light in the wavelength band of about 580 nm to 800 nm. The long cut blue light LBlc1, green light LG, and red light LR constituting the illumination light LW1 are mainly reflected by the B pixel corresponding to the long cut blue light LBlc1, and mainly reflected by the G pixel, red light corresponding to the green light LG. Reflected light corresponding to the light LR is mainly received by the R pixels.

  As shown in FIG. 12, the image sensor 56 performs an accumulation operation for accumulating signal charges in a pixel and a read operation for reading the accumulated signal charges within an acquisition period of one frame. The semiconductor light sources 35 to 37 are turned on in synchronization with the accumulation operation timing of the image sensor 56, and illumination light LW1 (LBlc1 + LG + LR) composed of mixed light of the long cut blue light LBlc1, green light LG, and red light LR is present at the observation site. The reflected light is incident on the image sensor 56. The image sensor 56 separates the reflected light of the illumination light LW1 using a micro color filter. The B pixel receives reflected light corresponding to the long cut blue light LBlc1, the G pixel receives reflected light corresponding to the green light LG, and the R pixel receives reflected light corresponding to the red light LR. The image sensor 56 sequentially outputs the image signals B, G, and R for one frame in which the pixel values of each of the B, G, and R pixels are mixed according to the frame rate in accordance with the readout timing.

  In FIG. 3, the processor device 12 includes a DSP (Digital Signal Processor) 66, an image processing unit 67, a frame memory 68, and a display control circuit 69 in addition to the controller 65. The controller 65 has a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores control programs and setting data necessary for control, a RAM (Random Access Memory) that loads programs and functions as a working memory, and the like. The CPU controls each part of the processor device 12 by executing a control program.

  The DSP 66 acquires an image signal output from the image sensor 56. The DSP 66 separates an image signal in which signals corresponding to B, G, and R pixels are mixed into B, G, and R image signals, and performs pixel interpolation processing on the image signals of the respective colors. As a result, B, G, and R image signals are assigned to each pixel. In addition, the DSP 66 performs signal processing such as gamma correction and white balance correction on the B, G, and R image signals.

  Further, the DSP 66 calculates the exposure value based on the image signals B, G, and R, and increases the light amount of the illumination light when the light amount of the entire image is insufficient (underexposure). Is too high (overexposure), an exposure control signal for controlling to reduce the amount of illumination light is output to the controller 65. The controller 65 transmits an exposure control signal to the light source control unit 42 of the light source device 13.

  The frame memory 68 stores image data output from the DSP 66 and processed image data processed by the image processing unit 67. The display control circuit 69 reads out image processed image data from the frame memory 68, converts it into a video signal such as a composite signal or a component signal, and outputs it to the monitor 14.

  The image processing unit 67 generates an observation image based on the image signals B, G, and R that have been color-separated into B, G, and R colors by the DSP 66. This observation image is output to the monitor 14. The image processing unit 67 updates the observation image every time the image signals B, G, and R in the frame memory 68 are updated. The image signal B includes a component of reflected light corresponding to the long cut blue light LBlc1 constituting the illumination light LW1. As described above, since the long-cut blue light LBlc1 is light in which all the light components in the wavelength band of 450 nm or more that hinder the improvement of the contrast of the surface blood vessels are cut, the surface blood vessels are rendered with high contrast. In lesions such as cancer, there is a tendency for the density of superficial blood vessels to be higher than that of normal tissues. Is preferably drawn clearly.

  The image processing unit 67 includes an enhancement processing unit 70 that performs processing for enhancing the surface blood vessels on the image signals B, G, and R.

  Here, in the image 71 (hereinafter referred to as B image) 71 represented by the image signal B of each pixel, the surface blood vessels 72 are depicted with high contrast as shown by thick lines and thin hatching in FIG. As shown only in FIG. 2, the middle-layer blood vessel 73 is also reflected somewhat. This is because the middle-layer blood vessel also absorbs light in a wavelength band lower than 450 nm. However, the reflection of the middle-layer blood vessel 73 in the B image 71 is not much more than when light having a wavelength band of 450 nm or more is irradiated. On the other hand, in an image 74 (hereinafter referred to as G image) 74 represented by the image signal G of each pixel, as shown by a thick line and thin hatching in FIG. It is drawn. The surface blood vessels 72 are also slightly reflected as shown by thin lines only. Since the image signal G includes a component of reflected light corresponding to the green light LG having a wavelength band of 530 nm to 560 nm in which the absorption of the middle layer blood vessel 73 is larger than that of the surface layer blood vessel 72, the G image 74 is highlighted. Contrary to the B image 71, the middle layer blood vessel 73 is formed.

  The enhancement processing unit 70 performs processing for suppressing the contour of the middle-layer blood vessel 73 and relatively enhancing the contour of the surface blood vessel 72. Specifically, the region of the middle blood vessel 73 in the G image 74 is extracted, and the pixel value of the region of the middle blood vessel 73 extracted in the G image 74 in the full color image generated based on the image signals B, G, and R Then, the difference between the pixel values of other regions adjacent to the region of the middle layer blood vessel 73 (the surface layer blood vessel 72 and the mucosal surface) is reduced, and the region of the middle layer blood vessel 73 and the other region are assimilated. The image processing unit 67 outputs a full-color image that has undergone the contour suppression process as an observation image. It should be noted that the region of the surface blood vessel 72 in the B image 71 is extracted, the difference in pixel value between the extracted surface blood vessel 72 region and other regions is widened, and the contour enhancement processing is performed on the region of the surface blood vessel 72. The applied full color image may be used as an observation image.

  In FIG. 15, an optical path integrating unit 41 is a light guide for collimating lenses 80, 81, and 82, dichroic mirrors 83 and 84 for collimating each color light emitted from each of the semiconductor light sources 35 to 37, and light emitted from the optical path integrating unit 41. And a condensing lens 85 that condenses light at the incident end 55a of the light. Each of the dichroic mirrors 83 and 84 is an optical member in which a dichroic filter having a predetermined transmission characteristic is formed on a transparent glass plate.

  The green semiconductor light source 36 is disposed at a position where its optical axis coincides with the optical axis of the light guide 55. The green semiconductor light source 36 and the red semiconductor light source 37 are arranged so that their optical axes are orthogonal to each other. A dichroic mirror 83 is provided at a position where the optical axes of the green semiconductor light source 36 and the red semiconductor light source 37 are orthogonal to each other. Similarly, the blue semiconductor light source 35 is also arranged to be orthogonal to the optical axis of the green semiconductor light source 36, and a dichroic mirror 84 is provided at a position where these optical axes are orthogonal. The dichroic mirror 83 is disposed at an angle of 45 ° with respect to the optical axes of the green semiconductor light source 36 and the red semiconductor light source 37, and the dichroic mirror 84 is inclined with respect to the optical axes of the blue semiconductor light source 35 and the green semiconductor light source 36, respectively.

  As shown in FIG. 16, the dichroic filter of the dichroic mirror 83 has a characteristic of reflecting light in the red wavelength band of about 610 nm or more and transmitting light in the blue and green wavelength bands of less than that. The dichroic mirror 83 transmits the green light LG incident from the green semiconductor light source 36 via the collimator lens 81 downstream, and reflects the red light LR incident from the red semiconductor light source 37 via the collimator lens 82. Thereby, the optical paths of the green light LG and the red light LR are integrated.

  As shown in FIG. 17, the dichroic filter of the dichroic mirror 84 has a characteristic of reflecting light in the blue wavelength band of less than about 470 nm and transmitting light in the green and red wavelength bands higher than that. For this reason, the dichroic mirror 84 transmits the green light LG transmitted through the dichroic mirror 83 and the red light LR reflected by the dichroic mirror 83. Further, the dichroic mirror 84 reflects the long-cut blue light LBlc1 that has entered through the LCF 48 and the collimator lens 80. By this dichroic mirror 84, all the optical paths of the long cut blue light LBlc1, the green light LG, and the red light LR are integrated to generate the illumination light LW1.

  Hereinafter, the operation of the above configuration will be described. When performing an endoscopic diagnosis, the endoscope 11 is connected to the processor device 12 and the light source device 13, the processor device 12 and the light source device 13 are turned on, and the endoscope system 10 is activated.

  The insertion part 16 of the endoscope 11 is inserted into the subject's digestive tract, and observation in the digestive tract is started. The light source control part 42 sets the drive current value given to each LED 43-45, and starts lighting of each semiconductor light source 35-37. Then, the light amount control is performed while maintaining the target emission spectrum.

  Each of the semiconductor light sources 35 to 37 emits blue light LB, green light LG, and red light LR by the LEDs 43 to 45, respectively. The blue light LB passes through the LCF 48 and becomes long-cut blue light LBlc1. The long cut blue light LBlc1, the green light LG, and the red light LR are incident on the collimator lenses 80 to 82 of the optical path integration unit 41, respectively.

  The blue light LB has a peak wavelength of 455 nm and a wavelength component in the vicinity of 440 nm to 470 nm. As described with reference to FIG. 29, the light component in the wavelength band of 450 nm or more of the blue light LB is cut in order to increase the contrast difference between the surface blood vessel and the middle blood vessel and to draw the surface blood vessel with high contrast. You had better. Therefore, in the present embodiment, a long wavelength component of 450 nm or more is cut by the LCF 48 so that the contrast of the surface blood vessel is not deteriorated.

  The long cut blue light LBlc1 is reflected by the dichroic mirror 84. The green light LG passes through the dichroic mirrors 83 and 84. The red light LR is reflected by the dichroic mirror 83 and passes through the dichroic mirror 84. By the dichroic mirrors 83 and 84, the optical paths of the long cut blue light LBlc1, the green light LG, and the red light LR are integrated. The long cut blue light LBlc1, green light LG, and red light LR are incident on the condenser lens 85. Thereby, illumination light LW1 composed of long cut blue light LBlc1, green light LG, and red light LR is generated. The condensing lens 85 condenses the illumination light LW1 on the incident end 55a of the light guide 55 of the endoscope 11 and supplies the illumination light LW1 to the endoscope 11.

  In the endoscope 11, the illumination light LW 1 is guided to the illumination window 22 through the light guide 55 and is irradiated from the illumination window 22 to the observation site. The reflected light of the illumination light LW1 reflected at the observation site enters the image sensor 56 from the observation window 23. The image sensor 56 outputs the image signals B, G, and R to the DSP 66 of the processor device 12. The DSP 66 separates the image signals B, G, and R and inputs them to the image processing unit 67. The imaging operation by the imaging device 56 is repeated at a predetermined frame rate.

  The enhancement processing unit 70 performs a process of enhancing the surface blood vessels on the input image signals B, G, and R. The image processing unit 67 generates an observation image based on the image signals B, G, and R subjected to this enhancement processing. The observation image is output to the monitor 14 through the display control circuit 69. The observation image is updated according to the frame rate of the image sensor 56.

  The DSP 66 calculates an exposure value based on the image signals B, G, and R, and transmits an exposure control signal corresponding to the calculated exposure value to the light source control unit 42 of the light source device 13. Based on the received exposure control signal, the light source control unit 42 determines the drive current value of each of the semiconductor light sources 35 to 37 so that the ratio of the light amount of each color light becomes constant (so that the target emission spectrum does not change). . And each semiconductor light source 35-37 is driven with the determined drive current value. Thereby, the light quantities of the long cut blue light LBlc1, the green light LG, and the red light LR constituting the illumination light LW1 by the semiconductor light sources 35 to 37 can be kept constant at a ratio suitable for observation.

  Since the light amounts of the blue light LB, the green light LG, and the red light LR can be controlled independently, it is easy to generate the illumination light LW1 having a target emission spectrum, while maintaining the target emission spectrum. It is also easy to control the exposure of illumination light.

  The long cut blue light LBlc1 constituting the illumination light LW1 does not contain any component that deteriorates the contrast of the surface blood vessels on the observation image. Further, the enhancement processing unit 70 performs a process of enhancing the surface blood vessels. Conventionally, only the process of emphasizing the superficial blood vessels has been performed, but in the present invention, in addition to this, the light component that deteriorates the contrast of the superficial blood vessels on the observation image is removed by the LCF 48. For this reason, it is possible to obtain an observation image suitable for finer observation of the superficial blood vessel in which the difference between the superficial blood vessel and the middle blood vessel is clearly discriminated.

  The position of the LCF 48 is not limited to the position between the blue semiconductor light source 35 and the collimator lens 80 exemplified in the first embodiment, and may be on the optical path of the blue light LB. For example, the LCF 48 may be disposed between the collimator lens 80 and the dichroic mirror 84.

  The LCF 48 may have, for example, a bandpass characteristic that transmits light of 400 nm or more and less than 450 nm. However, a filter having a bandpass characteristic is more expensive to manufacture than a filter having the shortpass characteristic exemplified in the first embodiment. Therefore, as in the first embodiment, the LCF 48 having a shortpass characteristic is more costly. Is advantageous.

  The wavelength of the intersection point P of the reflectance of the surface blood vessel and the middle blood vessel is not limited to 450 nm when the thickness of the surface blood vessel is 10 μm exemplified in the first embodiment, but depends on the thickness of the surface blood vessel to be observed. As the thickness of the superficial blood vessel increases, the wavelength of the intersection P shifts to the longer wavelength side. Specifically, the wavelength of the intersection point P can take a value in the range of 445 nm to 460 nm. For this reason, the wavelength cut by the LCF 48 is also determined according to the thickness of the surface blood vessel to be observed.

  For example, when the wavelength of the intersection P is 460 nm, the LCF 48 reflects light in the green and red wavelength bands having a wavelength of 460 nm or more and transmits light in the blue wavelength band of less than that, as shown in FIG. What has is used. The blue light LB becomes the long cut blue light LBlc2 shown in FIG. 19 by the LCF 48 having the transmission characteristics shown in FIG. The long cut blue light LBlc1 shown in FIG. 9 does not include the light component of the blue light LB with a peak wavelength of 455 nm, but the long cut blue light LBlc2 includes the light component of the blue light LB with a peak wavelength of 455 nm. ing. Therefore, the long cut blue light LBlc2 has a larger amount of light than the long cut blue light LBlc1. In this case, the emission spectrum of the illumination light LW2 that is a mixed light of the long cut blue light LBlc2, the green light LG, and the red light LR integrated by the optical path integration unit 41 is as shown in FIG. Note that the illumination light LW2 also has a continuous spectrum in the entire wavelength band, as with the illumination light LW1.

  In addition to the method exemplified in the first embodiment, the processing for emphasizing the superficial blood vessels is described in Japanese Patent Application Laid-Open No. 2011-098088 and Japanese Patent Application Laid-Open No. 2012-152459 of Patent Document 2. Other methods may be employed. For example, since the superficial blood vessel appears relatively thin on the observation image, the frequency component is biased to a relatively high frequency, and the B image 71 is subjected to frequency filtering to extract a high frequency component corresponding to the superficial blood vessel, By enhancing the surface blood vessels in the B image 71 with the extracted high frequency components, the contrast of the surface blood vessels is increased. Alternatively, the middle-low frequency component corresponding to the middle-layer blood vessel is extracted, and the contrast of the middle-layer blood vessel in the B image 71 is suppressed by the extracted middle-low frequency component, and the contrast of the surface blood vessel is relatively increased.

  As can be seen from the description of the contour suppression processing and the frequency enhancement processing, the processing for emphasizing the superficial blood vessel is sufficient if the contrast difference between the superficial blood vessel and the middle blood vessel is widened, and the contrast of the superficial blood vessel is increased with respect to the middle blood vessel. In addition to processing, nothing is done on the superficial blood vessels, but instead the contrast of the middle blood vessels is suppressed to relatively increase the contrast of the superficial blood vessels, and the contrast of the superficial blood vessels is increased, and the contrast of the middle blood vessels The process which suppresses is also included.

[Second Embodiment]
In the first embodiment, the LCF 48 is fixed to the front surface of the blue semiconductor light source 35 and the long wavelength component cutting function of the LCF 48 is always enabled, but the present invention is not limited to this. The LCF 48 cut function may be switched between valid and invalid.

  As shown in FIG. 21, the light source device 90 of this embodiment includes a mode switching unit 95. The mode switching unit 95 activates the cut function of the LCF 48 and emphasizes the superficial blood vessel for observation, and disables the cut function of the LCF 48 and observes the entire characteristics of the observation site. Switch between modes. Since the light source device 90 has the same configuration as that of the first embodiment except that the mode switching unit 95 is provided, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted. To do.

  The mode switching unit 95 includes a mode switching button 96, a long cut filter moving mechanism (hereinafter abbreviated as LCF moving mechanism) 97, and a light source control unit 98. The mode switching button 96 is connected to the light source control unit 98. The mode switching button 96 is an operation member that issues an instruction signal for mode switching to the light source control unit 98. For example, the front panel of the casing of the light source device 90 or the processor device 12 or the operation unit 17 of the endoscope 11 is used. Etc. are provided. Similarly to the light source control unit 42 of the first embodiment, the light source control unit 98 controls turning on / off of the LEDs 43 to 45 and the amount of light via the drivers 50 to 52, as well as from the mode switching button 96. The driving of the LCF moving mechanism 97 is controlled in accordance with the instruction signal.

  The LCF moving mechanism 97 includes, for example, a motor and a rack and pinion gear (both not shown) that changes the rotational force of the motor into a linear motion, and a set position indicated by a solid line disposed on the front surface of the blue semiconductor light source 35; The LCF 48 is slid and moved between the retracted position indicated by the dotted line retracted from the front surface of the blue semiconductor light source 35.

  When the LCF 48 is at the set position (when the cut function of the LCF 48 is enabled), the blue light LB is cut into a long wavelength component of 450 nm or longer and becomes the long cut blue light LBlc1 as in the first embodiment. The observation site is irradiated with illumination light LW1, which is a mixed light of long-cut blue light LBlc1, green light LG, and red light LR. On the other hand, when the LCF 48 is in the retracted position (when the cut function of the LCF 48 is invalidated), the blue light LB is incident on the optical path integration unit 41 as it is. The observation site is irradiated with illumination light LW0 having an emission spectrum as shown in FIG. 22, which is a mixed light of blue light LB, green light LG, and red light LR.

  The illumination light LW0 is obtained by superimposing the blue light LB directly on the green light LG and the red light LR, and has an emission spectrum close to that of white light irradiated when observing the entire properties of the conventional observation site. Since the illumination light LW0 is not processed to improve the contrast of the surface blood vessels to the blue light LB unlike the illumination light LW1, the illumination light LW0 is suitable for observing the entire properties of the observation site compared to the illumination light LW1. . Further, since the light component of the blue light LB is not cut, the amount of light is larger than that of the illumination light LW1.

  As described above, if the mode switching unit 95 is provided so that the operator can select to enable or disable the cut function of the LCF 48, the entire property of the observation site by white light that has been conventionally performed can be obtained. Both observation (normal observation mode) and superficial blood vessel enhancement observation (superficial blood vessel enhancement observation mode) can be performed. In the initial stage of observation, the normal observation mode is selected for observing the entire properties of the observation site, and when a lesion and a suspicious observation site are found, the surface blood vessel enhancement observation mode is selected. Further, when observing the entire properties of the observation site, the distal end portion 19 is often separated from the observation site, and the observation site is often imaged in a relatively distant view, so that the illumination light having an increased light intensity than the illumination light LW1 It is more advantageous to use LW0.

  Since the emission spectrum of illumination light is different between the normal observation mode and the superficial blood vessel enhancement observation mode, signal processing such as white balance correction performed by the DSP 66 is performed so that, for example, the color of the observation image is the same in each mode. It is preferable to change according to each mode.

  The enhancement processing unit 70 may operate in both modes, or may operate only in the superficial blood vessel enhancement observation mode.

  The moving mechanism of the LCF 48 is not limited to the motor and the rack and pinion gear exemplified above. For example, an LCF 48 is formed on one half of a visible light transmitting glass disc (turret), and the other half is not provided with blue light LB, and the disc is rotated by a motor. By doing so, the cut function of the LCF 48 may be validated or invalidated.

  Although the example in which the light source control unit controls the driving of the LCF moving mechanism 97 has been described, a control unit that controls the driving of the LCF moving mechanism 97 may be provided separately from the light source control unit.

  The LCF 48 is not limited to the one whose transmission characteristics do not change as in the above embodiments. For example, by driving an actuator such as a piezoelectric element, the surface distance of a substrate composed of two high-reflection optical filters is changed, so that birefringence is achieved between an etalon filter that controls the wavelength band of transmitted light and a polarizing filter. A filter having a variable transmission characteristic, such as a liquid crystal tunable filter configured to sandwich a filter and a nematic liquid crystal cell and controlling a wavelength band of transmitted light by changing a voltage applied to the liquid crystal cell, may be used. If a filter with variable transmission characteristics such as an etalon filter or a liquid crystal tunable filter is used, an LCF moving mechanism is not required, which is advantageous in terms of cost and space. When a filter with variable transmission characteristics such as an etalon filter or a liquid crystal tunable filter is used, the mode switching unit of the second embodiment changes the wavelength band of the transmitted light by driving the etalon filter or the liquid crystal tunable filter. And a control unit that controls driving of the etalon filter and the liquid crystal tunable filter via the driver.

[Third Embodiment]
In each of the above embodiments, the light source unit is configured by three semiconductor light sources 35 to 37 of blue, green, and red. However, the surface blood vessels closer to the mucosal surface layer of the surface blood vessels to be observed in each of the above embodiments ( Hereinafter, a violet semiconductor light source that emits light in a violet wavelength band for observing with emphasis on the superficial blood vessels for distinguishing from the superficial blood vessels to be observed in the above embodiments may be added.

  In FIG. 23, the light source device 110 of the present embodiment includes a light source unit 116 having a purple semiconductor light source 115 in addition to the semiconductor light sources 35 to 37 of each of the above embodiments, and each color light of each of the semiconductor light sources 35 to 37 and 115. And an optical path integration unit 117 that integrates the optical paths. The light source device 110 has the same configuration as that of the first embodiment except that the configurations of the light source unit and the optical path integrating unit are different. Therefore, the same reference numerals are given to the same configurations as those of the first embodiment. The description is omitted.

  The purple semiconductor light source 115 has a purple LED (not shown) that emits light in a purple wavelength band as a light emitting element. The specific structure of the purple semiconductor light source 115 is the same as that of the blue semiconductor light source 35 shown in FIG. As shown in FIG. 24, the violet semiconductor light source 115 has, for example, a wavelength component in the vicinity of 395 nm to 415 nm, which is a violet wavelength band, and emits violet light LV having a center wavelength of 405 ± 10 nm and a peak wavelength of 405 nm.

  The optical path integration unit 117 includes a collimator lens 118 that collimates the purple light LV, a long-cut blue light LBlc1, and a dichroic mirror 119 that integrates the optical path of the purple light LV in the optical path integration unit 41 of each of the above embodiments. It is. The optical path integration unit 117 integrates the optical paths of the long cut blue light LBlc1, the green light LG, the red light LR, and the violet light LV into one optical path. FIG. 25 shows an emission spectrum of the mixed light of the long cut blue light LBlc1, the green light LG, the red light LR, and the violet light LV integrated by the optical path integration unit 117. This mixed light is used as illumination light LW3.

  The blue semiconductor light source 35 and the violet semiconductor light source 115 are arranged so that their optical axes are orthogonal to each other, and a dichroic mirror 119 is provided at a position where these optical axes are orthogonal. The dichroic mirror 119 is arranged in a posture inclined by 45 ° with respect to the optical axes of the blue semiconductor light source 35 and the violet semiconductor light source 115.

  As shown in FIG. 26, the dichroic filter of the dichroic mirror 119 has a characteristic of reflecting light in the purple wavelength band of less than about 430 nm and transmitting light in the blue, green, and red wavelength bands higher than that. Yes. The dichroic mirror 119 transmits the long-cut blue light LBlc1 incident through the collimator lens 80 to the downstream side and reflects the purple light LV incident from the purple semiconductor light source 38 through the collimator lens 118. As a result, the optical paths of the long cut blue light LBlc1 and the purple light LV are integrated. The violet light LV reflected by the dichroic mirror 119 has a characteristic that the dichroic mirror 84 reflects light in a blue wavelength band of less than about 470 nm as shown in FIG. Head for. Thereby, the optical paths of all the long cut blue light LBlc1, green light LG, red light LR, and purple light LV are integrated.

  In FIG. 29, the reflectance of the superficial blood vessel is greatly reduced in the wavelength band below 450 nm, and is the lowest in the vicinity of 405 nm. When the observation region is irradiated with light having a wavelength band having a low reflectance, the blood vessel absorbs a large amount, so that an observation image having a difference in contrast between the blood vessel and the other portion can be obtained.

  Further, as shown in FIG. 27, the light scattering characteristics of the living tissue also have wavelength dependence, and the scattering coefficient μS increases as the wavelength becomes shorter. Scattering affects the depth of light penetration into living tissue. That is, the greater the scattering, the more light that is reflected near the mucosal surface layer of the biological tissue and the less light that reaches the mid-depth layer. Therefore, the shorter the wavelength, the lower the depth of penetration, and the longer the wavelength, the higher the depth of penetration.

  The violet light LV having a central wavelength of 405 ± 10 nm emitted from the violet semiconductor light source 115 has a relatively short wavelength and a low depth of penetration. Therefore, the extreme superficial blood vessel closer to the mucosal superficial layer among the superficial blood vessels to be observed in the above embodiments. The absorption by is large. For this reason, the purple light LV is used as special light for emphasizing the extreme surface blood vessels. By using the purple light LV, it is possible to obtain an observation image in which the extreme surface blood vessels are depicted with high contrast in addition to the surface blood vessels emphasized by the long-cut blue light LBlc1.

  In FIG. 28, when the extreme surface blood vessels are emphasized and observed, the purple semiconductor light source 115 is turned on in addition to the semiconductor light sources 35 to 37 in accordance with the accumulation operation timing of the image sensor 56. When each of the semiconductor light sources 35 to 37, 115 is turned on, the purple light LV is added together with the illumination light LW1, and the observation light is irradiated with the illumination light LW3 shown in FIG. 25 which is a mixed light (LW1 + LV).

  The illumination light LW3 obtained by adding the purple light LV to the illumination light LW1 is split by the micro color filter of the image sensor 56. The B pixel receives the reflected light corresponding to the purple light LV in addition to the reflected light corresponding to the long cut blue light LBlc1. Similarly to the first embodiment, the G pixel and the R pixel respectively receive reflected light corresponding to the green light LG and reflected light corresponding to the red light LR. The image sensor 56 sequentially outputs the image signals B, G, and R according to the frame rate in accordance with the readout timing.

  In this case, the image signal B includes a reflected light component corresponding to the purple light LV in addition to a reflected light component corresponding to the long-cut blue light LBlc1 constituting the illumination light LW1, and thus the surface blood vessel Not only the superficial blood vessels are depicted with high contrast. Similar to the superficial blood vessels, the light source device of the present embodiment is characterized by the pattern of the superficial blood vessels such as cancer tending to be denser of the superficial blood vessels compared to normal tissues. 110 is preferable because the blood vessel of the extreme surface layer is clearly depicted.

  In the first embodiment, the light amount control of each color light is performed by changing the drive current value given to each LED 43 to 45 based on the exposure control signal from the processor device 12. Due to the influence of deterioration over time, the output light quantity of the semiconductor light source may vary with respect to the drive current value. Therefore, a light quantity measurement sensor for measuring the light quantity of each color light may be provided to monitor whether or not the light quantity of each color light has reached the target value based on the light quantity measurement signal output from the light quantity measurement sensor.

  In this case, the light source control unit compares the light quantity measurement signal with the target light quantity, and gives to each of the semiconductor light sources 35 to 37 set in the exposure control so that the light quantity becomes a target value based on the comparison result. Fine-tune the drive current value. In this way, the light quantity of each color light is constantly monitored by the light quantity measurement sensor, and the light quantity can be controlled to always follow the target value by finely adjusting the drive current value given based on the measurement result of the light quantity. For this reason, the illumination light of the target emission spectrum can be obtained more stably.

  In each of the above embodiments, a semiconductor light source composed only of LEDs is cited. For example, a green semiconductor light source is excited with a blue excitation light LED that emits blue excitation light in a wavelength band from violet to blue, and blue excitation light. The fluorescent semiconductor light source may be configured of a green phosphor that emits green light in the green wavelength band. Also, instead of or in addition to the green semiconductor light source, the red semiconductor light source is replaced with a blue excitation light LED that emits blue excitation light in the purple to blue wavelength band, and red fluorescence in the red wavelength band excited by the blue excitation light. You may comprise with the red fluorescent substance which emits. When the red semiconductor light source is composed of a fluorescent semiconductor light source, the excitation light LED is not limited to the blue excitation light emitting element that emits blue excitation light in the purple to blue wavelength band, but green that emits green excitation light in the green wavelength band. An excitation light emitting element may be used. In this case, a fluorescent semiconductor light source is configured by encapsulating a phosphor instead of the resin 35c in the cavity of the mold 35b shown in FIG. 4 of the first embodiment.

  When the light emitted from the excitation light emitting element of the fluorescent semiconductor light source includes a component having a wavelength longer than the intersection point P of the reflectance of the surface blood vessel and the middle blood vessel, it is preferable to provide a filter for cutting the light component.

  Further, the LED mounting form shown in FIG. 4 is an example, and other forms may be adopted. For example, a microlens for adjusting the divergence angle may be provided on the light emission surface of the sealing resin 35c, or the LED may be housed in a shell-type case in which the microlens is formed instead of the surface mount type. . In addition, when a fluorescent semiconductor light source is used as a green semiconductor light source or a red semiconductor light source, the fluorescent semiconductor light source is not limited to one in which the excitation light LED and the phosphor are integrally provided, and may be provided separately. . In this case, a light guide member such as a lens or an optical fiber is added between the excitation light LED and the phosphor, and the excitation light of the excitation light LED is guided to the phosphor through the light guide member.

  Further, a laser diode (LD (Laser Diode)) may be used instead of an LED as a light emitting element of a fluorescent semiconductor. Organic EL (Electro-Luminescence) elements may be used in addition to LEDs and LDs. An LD or an organic EL element may be used as a light emitting element of another semiconductor light source without being limited to the fluorescent semiconductor light source.

  The configuration of the light source unit may be a combination of a white light source and a blue semiconductor light source instead of the blue, green, and red semiconductor light sources 35 to 37 exemplified in the above embodiments. As a white light source, a fluorescent white semiconductor light source composed of a white LED, a blue excitation light emitting element, and a phosphor that is excited by blue excitation light and emits fluorescence in a broad wavelength band from green to red is used. Alternatively, not only the semiconductor light source but also a xenon lamp or a metal halide lamp may be used.

  Moreover, you may comprise a light source part with the white light source and the filter turret arrange | positioned on the optical path of the white light which a white light source emits. The filter turret has an LCF 48 formed on the half surface of a disc made of visible light transmitting glass, the other half is not provided with anything, and transmits white light emitted from a white light source as it is, and is rotated by a motor or the like. . The LCF 48 cuts a light component of the white light having a wavelength longer than the intersection P of the reflectance of the surface blood vessel and the middle blood vessel to generate long cut blue light. In this case, the white light source also serves as the blue light source.

  In this case, the filter turret is sequentially rotated in synchronization with the accumulation operation of the image sensor 56, and the observation site is alternately irradiated with white light and long-cut blue light as illumination light. The image processing unit 67 generates an observation image based on an image signal obtained by irradiating white light and an image signal obtained by irradiating long cut blue light. The enhancement processing unit 70, for example, enhances the surface blood vessels by synthesizing a B image obtained by irradiating blue light with a full color image obtained by irradiating white light.

  In the above case where the white light source also serves as the blue light source, it is difficult to control the amount of blue light independently, so the blue light source is a single blue semiconductor light source as in the above embodiments, and the amount of blue light is independent. Therefore, a controllable configuration is more preferable. In addition, by using a blue light source as a single blue semiconductor light source, the amount of blue light LB and long-cut blue light can be increased compared to the case where a white light source also serves as a blue light source, thereby improving the visibility of surface blood vessels. This is more preferable.

  The configuration of the optical path integration unit in each of the above embodiments is an example, and various modifications can be made. For example, although a dichroic mirror is used as an optical member on which a dichroic filter is formed, a dichroic prism in which a dichroic filter is formed on the prism may be used instead. Further, instead of an optical member formed with a dichroic filter, such as a dichroic mirror or a dichroic prism, for example, a plurality of incident ends facing each semiconductor light source and one exit end facing an incident end of an endoscope light guide The optical path may be integrated using a branched light guide having The branching light guide is a fiber bundle in which optical fibers are bundled. The optical fiber is divided into a plurality of predetermined numbers at one end, and the incident end is branched into a plurality. In this case, each semiconductor light source is arranged corresponding to each branched incident end.

  An observation image may be acquired based on the green light LG by irradiating the observation site with mixed light of long cut blue light and green light LG or mixed light of green light LG and purple light LV.

  In each of the above embodiments, the image sensor 56 has a color image sensor that separates illumination light by B, G, and R micro color filters, and B, G, and R image signals are simultaneously acquired by the color image sensor. The simultaneous endoscope system and the light source device used therefor have been described as an example, but it has a monochrome imaging device and sequentially irradiates each color light of blue, green and red, and outputs B, G, and R image signals. The present invention may be applied to a field-sequential endoscope system that obtains a field-sequential and a light source device used therefor.

  Needless to say, each of the above embodiments can be implemented alone or in combination.

  In each of the above-described embodiments, the light source device and the processor device are described as separate components. However, the two devices may be configured integrally. The present invention also relates to an endoscope system using a fiberscope that guides reflected light of an observation site of illumination light with an image guide, and an ultrasonic endoscope in which an image pickup element and an ultrasonic transducer are built in a tip portion. It can also be applied to a light source device used therefor.

DESCRIPTION OF SYMBOLS 10 Endoscope system 11 Endoscope 13, 90, 110 Light source device 35 Blue semiconductor light source 36 Green semiconductor light source 37 Red semiconductor light source 40, 116 Light source part 41, 117 Light path integration part 42, 98 Light source control part 43 Blue LED
48 Long cut filter (LCF)
55 Light guide 56 Image sensor 95 Mode switching unit 96 Mode switching button 97 Long cut filter (LCF) moving mechanism 115 Purple semiconductor light source

Claims (11)

A blue light source emitting blue light in the blue wavelength band;
The intersection of the reflectance of the surface blood vessel and the middle layer blood vessel in the reflection spectrum of the surface layer blood vessel present in the mucosal surface layer of the living tissue and the middle layer blood vessel present in the middle layer of the blue light provided on the optical path of the blue light A long cut filter that cuts at least a part of a long wavelength component equal to or greater than
An endoscope system comprising:   The endoscope system according to claim 1, wherein the wavelength of the intersection is a value in a range of 445 nm to 460 nm.   The endoscope system according to claim 2, wherein a wavelength of the intersection is 450 nm.   The endoscope system according to any one of claims 1 to 3, wherein the blue light source is a blue semiconductor light source having a blue semiconductor light emitting element.   The endoscope system according to claim 4, wherein the blue semiconductor light emitting element is a blue light emitting diode. A green semiconductor light source emitting green light in the green wavelength band;
A red semiconductor light source emitting red light in the red wavelength band;
6. The endoscope system according to claim 4, further comprising: an optical path integrating unit that integrates optical paths of the respective color lights emitted from the green semiconductor light source, the red semiconductor light source, and the blue semiconductor light source.   The endoscope system according to claim 6, wherein the green semiconductor light source, the red semiconductor light source, and the blue semiconductor light source emit light of each color at the same time. Activate the cut function of the long cut filter, superficial blood vessel emphasis observation mode that emphasizes and observes the superficial blood vessels,
The endoscope system according to claim 1, further comprising a mode switching unit that disables the cutting function and switches between a normal observation mode for observing an observation site. The mode switching unit is an operation member that issues an instruction signal for instructing mode switching.
A long cut filter moving mechanism for moving the long cut filter between a set position arranged on the optical path of the blue light and a retreat position for retracting from the optical path of the blue light;
The endoscope system according to claim 8, further comprising a control unit that controls driving of the long cut filter moving mechanism in response to an instruction signal from the operation member.   2. A purple semiconductor light source that emits purple light in a purple wavelength band for emphasizing and observing a superficial blood vessel closer to the mucosal surface layer among the superficial blood vessels present on the mucosal surface layer of a living tissue. The endoscope system according to any one of Items 9 to 9. An imaging device that images an observation object illuminated by illumination light including long-cut blue light in which at least a part of a long wavelength component equal to or greater than the wavelength of the intersection is cut, and outputs an image signal;
The endoscope system according to claim 1, further comprising: an enhancement processing unit that performs a process of enhancing the surface blood vessel on the image signal.

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