WO2015029709A1

WO2015029709A1 - Endoscope system

Info

Publication number: WO2015029709A1
Application number: PCT/JP2014/070553
Authority: WO
Inventors: 永治大橋; 小澤　聡; 美範森本; 祐樹寺川
Original assignee: 富士フイルム株式会社
Priority date: 2013-08-27
Filing date: 2014-08-05
Publication date: 2015-03-05
Also published as: JP6391772B2; JP2018171540A; JP6827512B2; JP2020018914A; JP2017185267A; JPWO2015029709A1; JP6162809B2; JP6615959B2

Abstract

The purpose of the present invention is to obtain observed images in which the contrast of superficial blood vessels has been enhanced and to observe superficial blood vessels in more detail. A long cut filter (LCF)(48) is provided on the front surface of a blue semiconductor light source (35). Of the blue light (LB) emitted by the blue semiconductor light source (35), the LCF (48) cuts the long wavelength components at or above the wavelength (450 nm) of the intersection point (P) of the reflectances of the superficial blood vessels and the intermediate layer blood vessels in the reflection spectra of the superficial blood vessels present in the superficial layer of the mucosa of living tissue and the intermediate layer blood vessels present in the intermediate layer and generates a long cut blue light (LBlc1). A mixed light of said long cut blue light (LBlc1), green light (LG) and red light (LR) is irradiated on a region to be observed and an image is captured by an image pickup element (56). A highlighting section (70) performs processing on the image signal output from the image pickup element (56) to highlight the superficial blood vessels.

Description

Endoscope system

The present invention relates to an endoscope system.

In the medical field, endoscopic diagnosis using an endoscopic system is in widespread use. An endoscope system includes an endoscope, an endoscope light source device (hereinafter simply referred to as a light source device) for supplying illumination light to the endoscope, and a processor device that processes an image signal output from the endoscope. Is equipped. The endoscope has an insertion portion to be inserted into a living body. At the tip of the insertion portion, an illumination window for illuminating the observation site (subject) with illumination light, and an observation window for photographing the observation site are disposed. The endoscope incorporates a 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 device such as a CCD is disposed at the back of the observation window. The observation site irradiated with the illumination light is imaged by the imaging device, and the processor device generates an observation image based on the image signal output from the imaging device. An observation image is displayed on a monitor and observation in a living body is performed.

In recent endoscopic diagnosis, special light (narrow band light) limited to a specific wavelength band is used in contrast to the conventional observation for grasping the overall property of the surface of a living tissue under white light. The observation used is also actively performed. Although there are various types of observation using special light, the blood vessels present in the mucous membrane of biological tissue are emphasized and displayed by using the optical property that the depth of light into the biological tissue differs depending on the wavelength. The blood-vessel emphasis observation is known (refer patent document 1, 2). In abnormal tissues such as cancer occurring in living tissues, the state of blood vessels is different from that of normal tissues, and therefore, blood vessel emphasis observation has been found useful for the detection of early-stage cancer and the like.

In the light source devices described in Patent Documents 1 and 2, in addition to a light source emitting white light, a blue semiconductor emitting, for example, a narrow band blue light having a central wavelength of about 445 nm which is well absorbed by surface blood vessels present in mucosal surface A light source is provided as a light source of special light. Each of the light sources is turned on to simultaneously irradiate white light and blue light to the observation site, and the reflected light is imaged by the imaging device to obtain 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 a superficial blood vessel is further emphasized, processing for emphasizing the superficial blood vessel is performed on the image signal output from the imaging device.

JP, 2011-098088, A Unexamined-Japanese-Patent No. 2012-152459

By the way, the present inventors found the relationship between the reflection spectra of the mucous membrane, the superficial blood vessel, and the middle blood vessel shown in FIG. In FIG. 29, the reflection spectrum of the mucous membrane is shown by a two-dot chain line, the reflection spectrum of the superficial blood vessel is shown by a solid line, and the reflection spectrum of the middle layer blood vessel is shown by a dotted line. The surface blood vessel is a 10 μm thick blood vessel located at a depth of 10 μm from the mucosal surface, and the middle blood vessel is a 10 to 20 μm thick blood vessel existing at a 50 μm depth from the mucosal surface. It shows.

The reflectance of superficial blood vessels is greatly reduced in the wavelength band below 450 nm, and the difference with the reflectance of middle-layer blood vessels and mucous membranes is large. On the other hand, the reflectance of the middle layer blood vessel is lowered in the wavelength band of 530 nm to 560 nm although not to the extent of the surface layer blood vessel, and the difference with the reflectance of the surface layer blood vessel and the mucous membrane is large. The reflectance of the mucous membrane is larger than the reflectance of the superficial blood vessels and the middle blood vessels in all wavelength bands.

Focusing on changes in the reflectivity of the superficial and middle layer vessels, in the wavelength band below 450 nm, the reflectivity of the superficial layer is lower than that of the middle layer, and the reflectivity of the middle and outer layers is the same at around 450 nm, 450 nm In the above wavelength band, the magnitude of the reflectance is reversed, and the reflectance of the middle-layer blood vessel is lower than that of the superficial blood vessel. That is, when light in a wavelength band below 450 nm is irradiated, the surface blood vessels are enhanced on the observation image because they absorb light better, and when light in a wavelength band of 450 nm or more is irradiated, conversely, Is emphasized on the observation image. Therefore, when the surface blood vessels are to be observed, the difference between the surface blood vessels and the middle blood vessels is the smaller the light component of the wavelength band of 450 nm or more, which is the intersection of the reflectance of the surface blood vessels and the middle blood vessels shown by the symbol P It turns out that it is good because a clearly distinguishable high contrast observation image can be obtained.

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

The present invention has been made in view of the above problems, and is to obtain an observation image in which the contrast of the surface blood vessel is made more prominent in surface blood vessel enhancement observation in which the surface blood vessel present in the mucosal surface of living tissue is emphasized and observed. It is an object of the present invention to provide an endoscope system capable of observing a superficial blood vessel more precisely.

In order to achieve the above object, the endoscope system of the present invention has 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 the blue light, and among the blue light, in the reflection spectra of the superficial blood vessels present in the mucous surface of the living tissue and the middle layer blood vessels present in the middle layer, At least a part of the long wavelength component longer than the wavelength of the intersection is cut.

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 device is, for example, a blue light emitting diode.

A light path integrating the light paths of the green semiconductor light source emitting green light in the green wavelength band, the red semiconductor light source emitting red light in the red wavelength band, the green semiconductor light source, the red semiconductor light source, and the blue semiconductor light source It is preferable to have an integrated part.

The green semiconductor light source, the red semiconductor light source, and the blue semiconductor light source emit light of each color simultaneously, and the imaging device is a color imaging device having blue, green and red micro color filters, and blue, green and red image signals It is preferable to output.

A mode switching unit is provided that switches between a surface blood vessel enhancement observation mode for emphasizing and observing a surface blood vessel by disabling the cut function of the long cut filter and a normal observation mode for observing the observation site by disabling the cut function. Is preferred. The mode switching unit is, for example, long between an operation member that issues an instruction signal for instructing mode switching, a set position disposed on the optical path of blue light, and a retracted position retracted from the optical path of blue light It has a long cut filter moving mechanism which moves a cut filter, and a control unit which controls driving of the long cut filter moving mechanism according to an instruction signal from an operation member.

The light source device for an endoscope has a purple semiconductor light source that emits violet light of a purple wavelength band for emphasizing and observing a near surface blood vessel closer to the mucosal surface of the surface blood vessels present in the mucosal surface of living tissue. It may be done.

An image pickup element which picks up an image of an observation target illuminated by illumination light including long cut blue light from which at least a part of a long wavelength component of the intersection or more is cut, and outputting an image signal; It is preferable to have an emphasizing processing unit for emphasizing a superficial blood vessel.

According to the present invention, among the blue light in the blue wavelength band emitted by the blue light source, the reflectances of the surface blood vessels and the middle blood vessels in the reflection spectrum of the surface blood vessels present in the mucous surface 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 longer than the wavelength of the point of intersection is cut, it is possible to obtain an observation image in which the contrast of the superficial blood vessel is made more pronounced, and the superficial blood vessel can be observed more finely.

It is an outline view of an endoscope system of the present invention. It is a front view of the 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 with 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 pick-up element. 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 the middle layer blood vessel drawn by B image. It is a figure which shows the surface blood vessel and the 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 unifies 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 unifies the optical path of blue light, green light, and red light. It is a graph which shows the permeation | transmission characteristic of a long cut filter in case the wavelength of intersection P of the reflectance of a superficial blood vessel and a middle layer 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 with 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 with 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 with 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 unifies 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 an extremely superficial blood vessel, and the operation timing of an imaging element. It is a graph which shows the reflection spectrum of a mucous membrane, a superficial blood vessel, and a middle layer blood vessel.

First Embodiment
In FIG. 1, an endoscope system 10 includes an endoscope 11 for imaging an observation site in a living body, a processor device 12 for generating an observation image of the observation site based on an image signal obtained by imaging, and an observation site The light source device 13 supplies illumination light for irradiating the light to the endoscope 11, and the monitor 14 displays the observation image. An operation input unit 15 such as a keyboard or a mouse is connected to the processor unit 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 A universal cord 18 is provided.

The insertion part 16 is comprised by the front-end | tip part 19, the bending part 20, and the flexible tube part 21 continuously provided in order from the front-end | tip. As shown in FIG. 2, an illumination window 22 for irradiating illumination light to the observation site, an observation window 23 for taking in an image of the observation site, and an air supply for cleaning the observation window 23 are provided on the tip surface of the tip portion 19. The air / water supply nozzle 24 for supplying water and the forceps outlet 25 for performing various treatments by projecting treatment tools such as forceps and electric scalpel are provided. Behind the observation window 23, an imaging device 56 and an objective optical system 60 for imaging (both see FIG. 3) are incorporated.

The bending portion 20 is composed of a plurality of connected bending pieces, and operates the angle knob 26 of the operation portion 17 to bend in the vertical and horizontal directions. The bending of the bending portion 20 orients the tip 19 in a desired direction. The flexible tube portion 21 is flexible so that it can be inserted into a tortuous conduit such as the esophagus or intestine. A communication cable for communicating a drive signal for driving the image sensor 56 and an image signal output from the image sensor 56, and a light guide 55 for guiding illumination light supplied from the light source device 13 to the illumination window 22 See FIG. 3) and the like.

In addition to the amble knob 26, the forceps port 27 for inserting a treatment tool, the air supply / water supply button 28 operated at the time of air supply / water supply from the air supply / water supply nozzle 24, and a still image A release button (not shown) or the like for shooting is provided.

A communication cable and a light guide 55 extended 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 side. The connector 29 is a composite type connector including a communication connector 29a and a light source connector 29b. The communication connector 29 a and the light source connector 29 b 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 configured of three

semiconductor light sources

35, 36 and 37 of blue, green and red, and an optical path integration unit that integrates optical paths of respective color lights of the semiconductor light sources 35 to 37. 41 and a light source control unit 42 for controlling the drive of each 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: Light Emitting Diode) 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 emitting light. Each of the LEDs 43 to 45 is a junction of a P-type semiconductor and an N-type semiconductor as is well known. When a voltage is applied, electrons and holes recombine across the band gap in the vicinity of the PN junction, current flows, and energy corresponding to the band gap is emitted as light at the time of recombination. The amount of light emitted from each of the LEDs 43 to 45 increases as the value of the supplied power increases.

As shown in FIG. 4, the blue semiconductor light source 35 is a substrate 35a on which the 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 And 35c. The inner surface of the cavity acts as a reflector that reflects light. A diffusion material for diffusing light is dispersed in the resin 35c. The blue LED 43 is conductively connected to the substrate 35 a by a wire 35 d. The mounting form of such a blue semiconductor light source 35 is generally called a surface mounting type. Since the semiconductor light sources 35 to 37 basically have 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 central wavelength of 455 ± 10 nm and a peak wavelength of 455 nm. Further, as shown in FIG. 6, the green semiconductor light source 36 has wavelength components around 500 nm to 600 nm which is a green wavelength band, for example, and emits green light LG having a central 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 a wavelength component in the vicinity of 615 nm to 635 nm which is a red wavelength band, for example, and emits red light LR having a central wavelength of 620 ± 10 nm and a peak wavelength of 625 nm. The center wavelength indicates the wavelength at the center of the width of the emission spectrum of each color light, and the peak wavelength indicates the wavelength of the peak of the mountain shape of the emission spectrum of each color light.

In FIG. 3, on the front surface of the blue semiconductor light source 35, a long cut filter (hereinafter, abbreviated as LCF) 48 is provided. Among the blue light LB emitted from the blue semiconductor light source 35, the LCF 48 has the reflectances of the surface blood vessels and the middle blood vessels in the reflection spectrum of the surface blood vessels present in the mucous surface of the living tissue and the middle layer blood vessels shown in FIG. The long wavelength component above the wavelength (450 nm) of the intersection point P of is cut. More specifically, as shown in FIG. 8, LCF 48 has the property of reflecting light in the green and red wavelength bands of wavelengths 450 nm or more and transmitting light in the blue wavelength band below 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 obtained by cutting all the light components in the wavelength band of 450 nm or more, which interfere with the improvement in the contrast of the superficial blood vessel described with reference to FIG. 29, of the blue light LB. The long cut blue light LBlc1 is incident on the light path integration unit 41.

In the LCF 48, the wavelength of the intersection P (to the extent that the contrast improvement of the superficial blood vessel can be sufficiently secured without completely cutting the long wavelength component of the intersection P (450 nm) or more (that is, 100% cut) Cut at least a part (eg, 80 to 95%) of the long wavelength component of 450 nm or more. As a result, the spectrum of the long cut blue light LBlc1 is not discrete with the spectrum of the green light LG on the longer wavelength side than that, but is continuous.

Drivers

50, 51 and 52 are connected to the LEDs 43 to 45, respectively. The light source control unit 42 controls the lighting, extinguishing, and the light quantity of the LEDs 43 to 45 through the drivers 50 to 52. The control of the light amount is performed 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.

Under the control of the light source control unit 42, the drivers 50 to 52 turn on the LEDs 43 to 45 by continuously applying a driving current to the LEDs 43 to 45. Then, according to the exposure control signal received from the processor unit 12, the supplied power to each of 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. Note that PAM (Pulse Amplitude Modulation) control that changes the amplitude of a drive current pulse by applying a drive current in a pulse shape instead of continuously supplying the pulse and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse You may

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 portion of the light path integrating portion 41 is disposed in the vicinity of the receptacle connector 54 to which the light source connector 29 b is connected. The optical path integration 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, protective glass is provided on each of the light source connector 29 b and the receptacle connector 54.

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 light path integration unit 41 is shown in FIG. This mixed light is used as illumination light LW1. The emission spectrum of the illumination light LW1 shown in FIG. 10 is an example, and the emission spectrum of the illumination light LW1 to be targeted may be variously changed according to the color tone and the like of the desired observation image. Specifically, the ratio of the light quantity of long cut blue light LBlc1, green light LG and red light LR (ratio of drive current value of each LED 43 to 45) is changed to generate illumination light LW1 of the target emission spectrum. . Here, as described above, the long cut blue light LBlc1 and the green light LG have a continuous spectrum, and the green light LG and the red light LR have a continuous spectrum, so that illumination The spectrum of the light LW1 is continuous over the wavelength band (about 400 to about 670 nm). Therefore, the illumination light LW1 has the same or similar color rendering as a xenon lamp whose spectrum is continuous over the entire wavelength band.

The light source control unit 42 performs exposure control of illumination light while maintaining a target emission spectrum. When the ratio of the light quantity of each color light constituting the illumination light changes, the emission spectrum of the illumination light changes and the color of the observation image changes. Therefore, the light source control unit 42 independently changes the drive current value given to each of the LEDs 43 to 45 through each of the drivers 50 to 52 to increase or decrease the amount of light of each color light so that the ratio of the light amount of each color light becomes constant.

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 in which a plurality of optical fibers are bundled. 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 in the light source connector 29 b faces the light emitting portion of the light path integration unit 41. The light emission end of the light guide 55 located at the front end portion 19 is branched into two at the front stage of the illumination window 22 so that light is guided to the two illumination windows 22.

An illumination lens 59 is disposed at 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 part.

An objective optical system 60 and an imaging device 56 are disposed at the back of the observation window 23. The image of the observation site enters the objective optical system 60 through the observation window 23 and is imaged on the imaging surface 56 a of the imaging device 56 by the objective optical system 60.

The image pickup device 56 is formed 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 image pickup surface 56a. The image sensor 56 photoelectrically converts the light received by the imaging surface 56 a and accumulates signal charges corresponding to the respective amounts of light received in the respective pixels. The signal charge is converted into a voltage signal by the amplifier and read out. The voltage signal is output from the imaging element 56 to the AFE 57 as an image signal.

AFE (Analog Front End) 57 is configured by a correlated double sampling circuit, an automatic gain control circuit, and an analog / digital converter (all not shown). The correlated double sampling circuit subjects the analog image signal from the imaging device 56 to correlated double sampling processing to remove noise due to the reset of the signal charge. 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 unit 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 element 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, and on the image pickup surface 56a, micro color filters of three colors B, G and R having spectral characteristics as shown in FIG. 11 are provided. Assigned to The array of micro color filters is, for example, a Bayer array.

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

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

In FIG. 3, the processor unit 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 central processing unit (CPU), a read only memory (ROM) for storing control programs and setting data necessary for control, and a random access memory (RAM) for loading a program and functioning as a working memory. The CPU executes the control program to control each part of the processor device 12.

The DSP 66 acquires an image signal output from the imaging device 56. The DSP 66 separates an image signal in which signals corresponding to the B, G, and R pixels are mixed into B, G, and R image signals, and performs pixel interpolation processing on the image signals of each color. Thus, B, G and R image signals are allocated to each pixel. In addition, the DSP 66 performs signal processing such as gamma correction and white balance correction on each of the B, G, and R image signals.

Also, the DSP 66 calculates the exposure value based on the image signals B, G, and R, and raises 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 is output to the controller 65 to control to reduce the light amount of the illumination light. 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 the image data subjected to image processing from the frame memory 68, converts the image data into a video signal such as a composite signal or a component signal, and outputs the video signal to the monitor 14.

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

The image processing unit 67 has an emphasizing processing unit 70 that performs processing for emphasizing the superficial blood vessels with respect to the image signals B, G, and R.

Here, in the image (hereinafter referred to as B image) 71 represented by the image signal B of each pixel, the surface layer blood vessel 72 is depicted with high contrast as shown by thick lines and light hatching in FIG. As shown only in the middle layer blood vessel 73 is also reflected somewhat. This is because the middle layer blood vessels also absorb some of the light in the wavelength band below 450 nm. However, the number of reflections of the middle-layer blood vessel 73 in the B image 71 is smaller than when the light of the wavelength band of 450 nm or more is irradiated. On the other hand, in the image (hereinafter referred to as a G image) 74 represented by the image signal G of each pixel, as shown by thick lines and light hatching in FIG. Depicted. Then, as shown by only thin lines, the superficial blood vessels 72 are also slightly reflected. The image signal G includes the component of the reflected light corresponding to the green light LG in the 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 superficial blood vessel 72. However, contrary to the B image 71, it becomes the middle layer blood vessel 73.

The emphasizing processing unit 70 suppresses the contour of the middle layer blood vessel 73 and relatively empties the contour of the superficial blood vessel 72. Specifically, in the full-color image generated based on the image signals B, G, and R by extracting the region of the middle layer blood vessel 73 in the G image 74, the pixel value of the region of the middle layer blood vessel 73 extracted in the G image 74 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 mucous membrane 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 the full color image subjected to the contour suppression processing as an observation image. Note that the region of the superficial blood vessel 72 in the B image 71 is extracted, the difference in pixel value between the extracted region of the superficial blood vessel 72 and the other region is expanded, and the edge enhancement process is performed on the region of the superficial blood vessel 72. The applied full color image may be used as the observation image.

In FIG. 15, the optical path integration unit 41 is a light guide for collimating the color light emitted from the semiconductor light sources 35 to 37,

collimator lenses

80, 81 and 82,

dichroic mirrors

83 and 84, and light emitted from the optical path integration unit 41. It comprises the condensing lens 85 which condenses to the incident end 55a of 55. FIG. Each

dichroic mirror

83, 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 disposed such 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 the 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 disposed at an angle of 45 ° with respect to the optical axes of the blue semiconductor light source 35 and the green semiconductor light source 36.

As shown in FIG. 16, the dichroic filter of the dichroic mirror 83 has the property of reflecting light in the red wavelength band of about 610 nm or more and transmitting light in the blue and green wavelength bands below that. The dichroic mirror 83 transmits the green light LG incident from the green semiconductor light source 36 through the collimator lens 81 to the downstream side, and reflects the red light LR incident from the red semiconductor light source 37 through 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 the property of reflecting light in the blue wavelength band less than about 470 nm and transmitting light in the green and red wavelength bands beyond that. Therefore, 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 incident 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, and the illumination light LW1 is generated.

Hereinafter, the operation of the above configuration will be described. When performing 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 powered on, and the endoscope system 10 is activated.

The insertion portion 16 of the endoscope 11 is inserted into the digestive tract of the subject to start observation in the digestive tract. The light source control unit 42 sets driving current values to be applied to the LEDs 43 to 45, and starts lighting of the semiconductor light sources 35 to 37. Then, the light amount control is performed while maintaining the target emission spectrum.

The semiconductor light sources 35 to 37 emit 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 a long cut blue light LBlc1. The long cut blue light LBlc 1, the green light LG, and the red light LR are respectively incident on the collimator lenses 80 to 82 of the light path integration unit 41.

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 to enhance the contrast difference between the surface blood vessels and the middle blood vessels and visualize the surface blood vessels 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 as not to cause the deterioration of the contrast of the superficial blood vessel.

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 transmitted through the dichroic mirror 84. The optical paths of the long cut blue light LBlc1, the green light LG, and the red light LR are integrated by the dichroic mirrors 83 and 84. The long cut blue light LBlc 1, the green light LG, and the red light LR are incident on the condensing lens 85. Thereby, the illumination light LW1 composed of the long cut blue light LBlc1, the green light LG, and the 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 LW1 is guided to the illumination window 22 through the light guide 55, and is irradiated onto the observation site from the illumination window 22. The reflected light of the illumination light LW1 reflected at the observation site is incident on the imaging device 56 from the observation window 23. The imaging device 56 outputs the image signals B, G and R to the DSP 66 of the processor unit 12. The DSP 66 color separates the image signals B, G, and R and inputs the image signals to the image processing unit 67. The imaging operation by the imaging element 56 is repeated at a predetermined frame rate.

The emphasizing processing unit 70 subjects the input image signals B, G, and R to a process of emphasizing a superficial blood vessel. The image processing unit 67 generates an observation image based on the image signals B, G, and R subjected to the 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 imaging device 56.

Further, 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. The light source control unit 42 determines the drive current value of each of the semiconductor light sources 35 to 37 based on the received exposure control signal so that the ratio of the light quantity of each color light becomes constant (the target emission spectrum does not change). . Then, the semiconductor light sources 35 to 37 are driven with the determined drive current value. As a result, the light amounts of the long cut blue light LBlc1, the green light LG, and the red light LR constituting the illumination light LW1 by the respective 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, the generation of the illumination light LW1 of the target emission spectrum is easy, and the target emission spectrum is maintained. It is also easy to control the exposure of the 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 vessel on the observation image. In addition, the emphasizing processing unit 70 performs a process of emphasizing a superficial blood vessel. Conventionally, only the processing for 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. Therefore, it is possible to obtain an observation image suitable for finer observation of the superficial blood vessels, in which the difference between the superficial blood vessels and the middle blood vessels is clearly distinguished.

The position of the LCF 48 is not limited to between the blue semiconductor light source 35 and the collimator lens 80 illustrated in the first embodiment, and it may be on the light 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 band pass characteristic of transmitting light of 400 nm or more and less than 450 nm. However, since the filter having the band pass characteristic has a manufacturing cost higher than that of the filter having the short path characteristic exemplified in the first embodiment, the LCF 48 having the short path characteristic is more costly as in the first embodiment. It is advantageous in terms of

The wavelength of the intersection point P of the reflectance of the superficial blood vessel and the middle layer blood vessel is not limited to 450 nm in the case where the thickness of the superficial blood vessel is 10 μm exemplified in the first embodiment, but it corresponds to the thickness of the superficial blood vessel to be observed. The wavelength of the intersection point P is also shifted to the long wavelength side as the thickness of the superficial blood vessel increases. Specifically, the wavelength of the intersection point P can take a value in the range of 445 nm to 460 nm. Therefore, the wavelength to be cut by the LCF 48 is also determined according to the thickness of the superficial blood vessel to be observed.

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

In addition to the method exemplified in the first embodiment, the processing for emphasizing superficial blood vessels is described in Japanese Patent Application Laid-Open No. 2011-098088 of Patent Document 1 and Japanese Patent Application Laid-Open No. 2012-152459 of Patent Document 2. May be adopted. For example, since the superficial blood vessels appear relatively thin on the observation image, the B image 71 is subjected to frequency filtering to extract the high frequency components corresponding to the superficial blood vessels by utilizing the fact that the frequency components are relatively high frequency. By emphasizing the superficial blood vessels in the B image 71 with the extracted high frequency components, the contrast of the superficial blood vessels is increased. Alternatively, the medium and low frequency components corresponding to the middle layer blood vessel are extracted, and the extracted medium and low frequency component suppresses the contrast of the middle layer blood vessel in the B image 71 and relatively increases the contrast of the superficial blood vessel.

As can be understood from the description of the contour suppression processing and the frequency enhancement processing, the processing for emphasizing the superficial blood vessel may be any processing that can spread the contrast difference between the superficial blood vessel and the middle layer blood vessel. Not limited to the treatment, nothing is done to 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 raised and the contrast of the middle blood vessels is increased Processing is 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 cut function of the long wavelength component of the LCF 48 is always enabled, but the present invention is not limited to this. The cut function of the LCF 48 may be switched on / off.

As shown in FIG. 21, the light source device 90 of the present embodiment includes a mode switching unit 95. The mode switching unit 95 activates the cut function of the LCF 48, and in the surface blood vessel enhancement observation mode for emphasizing and observing the surface blood vessel and the cut function of the LCF 48, invalidates the general function of the observation site. Switch between modes. The light source device 90 has the same configuration as that of the first embodiment except that the mode switching unit 95 is provided. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. 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, and, 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. Etc. are provided. Similar to the light source control unit 42 according to the first embodiment, the light source control unit 98 controls the lighting and extinguishing of each of the LEDs 43 to 45 and the light amount via the drivers 50 to 52, and controls the light 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) for converting the rotational force of the motor into linear motion, and a set position indicated by a solid line disposed on the front of the blue semiconductor light source 35; The LCF 48 is slidingly moved between a withdrawal position indicated by a dotted line which is withdrawn from the front surface of the blue semiconductor light source 35.

When the LCF 48 is in the set position (when the cut function of the LCF 48 is activated), as in the first embodiment, the long wavelength component of 450 nm or more of the blue light LB is cut to become long cut blue light LBlc1. The illumination light LW1 which is a mixed light of the long cut blue light LBlc1, the green light LG, and the red light LR is irradiated to the observation site. On the other hand, when the LCF 48 is at the retracted position (when the cut function of the LCF 48 is invalidated), the blue light LB is incident on the light 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 on the green light LG and the red light LR as it is, and has an emission spectrum close to the white light to be irradiated when observing the entire property of the conventional observation site. Since the illumination light LW0 is not processed to improve the contrast of the surface blood vessel with the blue light LB like the illumination light LW1, it is more suitable for observation of the entire property of the observation site than the illumination light LW1. . In addition, since the light component of the blue light LB is not cut, the light amount is larger than the illumination light LW1.

As described above, if the operator is able to select the mode switching unit 95 to enable or disable the cut function of the LCF 48, the entire characteristics of the observation site with the white light that is conventionally used can be obtained. Both observation (normal observation mode) and enhanced observation of superficial blood vessels (superficial blood vessel emphasis observation mode) can be performed. In the initial stage of observation, the normal observation mode is selected to observe the entire characteristics of the observation site, and when the lesion site is suspected and the observation site is suspected, the surface blood vessel enhancement observation mode can be selected. In addition, when observing the entire property of the observation site, the tip portion 19 is often separated from the observation site and the observation site is often imaged in a relatively distant view, so the illumination light whose light quantity is increased compared to the illumination light LW1 It is more advantageous to use LW0.

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

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

The moving mechanism of the LCF 48 is not limited to that constituted by the motor and the rack and pinion gear exemplified above. For example, LCF 48 is formed on one side of a disk (turret) made of visible light transmitting glass, and the other half is not provided with anything but blue light LB can be transmitted as it is, and the disk is rotationally moved by a motor By doing this, the cutting function of the LCF 48 may be enabled or disabled.

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 one in which the transmission characteristics do not change as in the above embodiments. For example, by driving an actuator such as a piezoelectric element to change the surface distance of a substrate comprising two high reflection light filters, an etalon filter for controlling the wavelength band of transmitted light, or birefringence between polarization filters A filter having variable transmission characteristics, such as a liquid crystal tunable filter configured by sandwiching a filter and a nematic liquid crystal cell and controlling a wavelength band of transmitted light by changing an applied voltage 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, the LCF moving mechanism is not necessary, 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 drives the etalon filter or the liquid crystal tunable filter to change the wavelength band of transmitted light. 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 of the three semiconductor light sources 35 to 37 of blue, green and red, but a superficial blood vessel closer to the mucosal surface (of the superficial blood vessels to be observed in each of the above embodiments) Hereinafter, a violet semiconductor light source may be added which emits light in a violet wavelength band for emphasizing and observing a superficial surface blood vessel in order to distinguish it from the superficial blood vessel to be observed in each of the above embodiments.

In FIG. 23, the light source device 110 of this embodiment includes the light source unit 116 having a purple semiconductor light source 115 in addition to the semiconductor light sources 35 to 37 of the above-described embodiments, and the respective color lights of the semiconductor light sources 35 to 37, 115 And an optical path integrating unit 117 for integrating the optical paths of 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 integration unit are different. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals. , I omit the explanation.

The violet semiconductor light source 115 includes, as a light emitting element, a violet LED (not shown) that emits light in a violet wavelength band. The specific structure of the violet 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 central wavelength of 405 ± 10 nm and a peak wavelength of 405 nm.

The optical path integration unit 117 adds the collimator lens 118 for collimating the purple light LV, the long cut blue light LBlc1, and the dichroic mirror 119 for integrating the optical paths of the purple light LV to the optical path integration unit 41 of each embodiment. 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 purple light LV into one optical path. The emission spectrum of the mixed light of the long cut blue light LBlc1, the green light LG, the red light LR, and the purple light LV integrated by the light path integration unit 117 is shown in FIG. This mixed light is used as illumination light LW3.

The blue semiconductor light source 35 and the purple semiconductor light source 115 are arranged such 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 to each other. The dichroic mirror 119 is disposed at an angle of 45 ° with respect to the optical axes of the blue semiconductor light source 35 and the purple semiconductor light source 115.

As shown in FIG. 26, the dichroic filter of the dichroic mirror 119 has the property of reflecting light in the violet wavelength band less than about 430 nm and transmitting light in the blue, green and red wavelength bands above that. There is. 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 violet semiconductor light source 38 through the collimator lens 118. Thereby, 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 of reflecting light in the blue wavelength band of less than about 470 nm as shown in FIG. Head for Thus, the light paths of all the long cut blue light LBlc1, the green light LG, the red light LR, and the purple light LV are integrated.

In FIG. 29, the reflectance of the superficial blood vessel falls largely in the wavelength band below 450 nm, and is most depressed near 405 nm. When light in a wavelength band having a low reflectance is applied to the observation site, an observation image in which the contrast between the blood vessel and the other part is different can be obtained because the absorption in the blood vessel is large.

Further, as shown in FIG. 27, the light scattering characteristics of the living tissue also have wavelength dependency, and the scattering coefficient μS becomes larger as the wavelength becomes shorter. Scattering affects the depth of light penetration into living tissue. That is, the larger the scattering, the more the light reflected near the mucous membrane surface of the living tissue, and the less the light reaching the middle deep layer. Therefore, the depth of penetration is lower as the wavelength is shorter, and the depth of penetration is higher as the wavelength is longer.

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

In FIG. 28, in the case of emphasizing observation on the superficial blood vessel, the purple semiconductor light source 115 is turned on in addition to the semiconductor light sources 35 to 37 in accordance with the timing of the accumulation operation of the imaging device 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.

The illumination light LW 3 in which the purple light LV is added to the illumination light LW 1 is dispersed by the micro color filter of the imaging device 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. Similar to the first embodiment, the G pixel and the R pixel respectively receive the reflected light corresponding to the green light LG and the reflected light corresponding to the red light LR. The imaging element 56 sequentially outputs the image signals B, G, and R according to the frame rate in accordance with the read timing.

The image signal B in this case includes the component of the reflected light corresponding to the purple light LV in addition to the component of the reflected light corresponding to the long-cut blue light LBlc1 constituting the illumination light LW1, so Not only extreme surface vessels are depicted with high contrast. Similar to the superficial blood vessels, in the lesion such as cancer, the density of the extreme superficial blood vessels tends to be higher than that of the normal tissue, and the light source device of the present embodiment is characterized by the extreme superficial blood vessel pattern. According to 110, it is preferable because the extreme superficial blood vessels are clearly depicted.

In the first embodiment, the light quantity control of each color light is performed by changing the drive current value to be applied to each of the LEDs 43 to 45 based on the exposure control signal from the processor device 12. Due to the influence of deterioration with time, the semiconductor light source may fluctuate in the amount of output light with respect to the drive current value. Therefore, a light quantity measurement sensor may be provided to measure the light quantity of each color light, and whether or not the light quantity of each color light has reached the target value may be monitored based on the light quantity measurement signal output by the light quantity measurement sensor.

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

In each of the above embodiments, a semiconductor light source constituted only by LEDs is mentioned, but for example, a green semiconductor light source is excited by a blue excitation light LED emitting blue excitation light in a wavelength band of violet to blue and blue excitation light It is good also as a fluorescence type semiconductor light source comprised with green fluorescent substance which emits green light of a green wavelength zone. Also, instead of or in addition to the green semiconductor light source, a red semiconductor light source is a blue excitation light LED that emits blue excitation light in a violet to blue wavelength band, and red fluorescence in red wavelength band excited by blue excitation light And red phosphors that emit light. When the red semiconductor light source is configured of a fluorescent semiconductor light source, the excitation light LED is not limited to a blue excitation light emitting element that emits blue excitation light in a violet to blue wavelength band, and green that emits green excitation light in a green wavelength band. It may be an excitation light emitting element. In this case, a fluorescent substance is sealed in place of the resin 35c in the cavity of the mold 35b shown in FIG. 4 of the first embodiment to constitute a fluorescent semiconductor light source.

When the light emitted from the excitation light emitting element of the fluorescent semiconductor light source contains a component having a wavelength equal to or greater than the intersection point P of the reflectance of the surface blood vessel and the middle layer blood vessel, a filter for cutting the light component is preferably provided.

Moreover, the mounting form of LED shown in FIG. 4 is one example, and another form may be adopted. For example, a micro lens may be provided on the light emitting surface of the sealing resin 35c to adjust the divergence angle, or the surface mount type may be used, and the form may be such that the LED is housed in a shell type case in which the micro lens is formed. . 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 the one in which the excitation light LED and the phosphor are integrally provided, but may be separately provided. . 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.

Furthermore, as a light emitting element of a fluorescent semiconductor, a laser diode (LD (Laser Diode)) may be used instead of the LED. In addition to LEDs and LDs, organic EL (Electro-Luminescence) elements may be used. An LD or an organic EL element may be used as a light emitting element of another semiconductor light source as well as the fluorescent type 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 one having 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 or the like configured with a white LED or a blue excitation light emitting element and a phosphor that emits fluorescence in a broad wavelength band of green to red excited by blue excitation light Not only a semiconductor light source but also a xenon lamp or a metal halide lamp may be used.

Also, the light source unit may be configured by a white light source and a filter turret disposed on the light path of the white light emitted by the white light source. In the filter turret, LCF 48 is formed on one side of a visible light transmitting glass disc, the other half is not provided with anything, and the white light emitted by the white light source is transmitted as it is, and is rotated by a motor etc. . The LCF 48 cuts the light component of the wavelength of the intersection point P of the reflectance of the surface layer blood vessel and the middle layer blood vessel in the white light to generate long cut blue light. In this case, the white light source doubles as the blue light source.

In this case, the filter turret is sequentially rotated in synchronization with the accumulation operation of the imaging element 56, and white light and long cut blue light are alternately emitted as illumination light to the observation site. 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 emphasizing processing unit 70 emphasizes superficial blood vessels, for example, by combining 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 doubles as the blue light source, it is difficult to control the light amount of blue light independently, so the blue light source is used as a single blue semiconductor light source as in the above embodiments and the blue light amount is independent. It is more preferable to have a controllable configuration. In addition, by using a blue light source as a single blue semiconductor light source, blue light LB and thus long cut blue light can be gained as compared with the case where a white light source doubles as a blue light source, and visibility of surface blood vessels is improved. It is more preferable because it can be

The configuration of the optical path integration unit in each of the above embodiments is an example, and various modifications are possible. 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 a prism may be used instead. Also, instead of an optical member on which a dichroic filter is formed, such as a dichroic mirror or a dichroic prism, for example, a plurality of incident ends facing each semiconductor light source and one emitting end facing an incident end of the light guide of the endoscope The light path may be integrated using a branched light guide having The branch-type light guide is a fiber bundle in which optical fibers are bundled, and a predetermined number of optical fibers are divided into a plurality at one end, and the incident end is branched into a plurality. In this case, the respective semiconductor light sources are disposed in correspondence with the respective branched incident ends.

A mixed light of long-cut blue light and green light LG, or a mixed light of green light LG and purple light LV may be irradiated on the observation site, and an observation image may be acquired on the basis of the green light LG.

In each of the above embodiments, the imaging device 56 includes a color imaging device that performs color separation of illumination light by the B, G, and R micro color filters, and simultaneously acquires B, G, and R image signals by the color imaging device. The simultaneous endoscope system and the light source device used in the endoscope system have been described as an example, but the image signal of B, G, R is provided by sequentially emitting blue, green and red color lights having a monochrome imaging element. The present invention may be applied to a plane-sequential type endoscope system for acquiring plane-sequentially and a light source device used therefor.

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

In each of the above embodiments, the light source device and the processor device are separately described. However, two devices may be integrated. The present invention also relates to an endoscope system using a fiberscope for guiding reflected light of an observation site of illumination light with an image guide, and an ultrasonic endoscope in which an imaging device and an ultrasonic transducer are built in the tip. And it can apply also to the light source device used for it.

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 Optical

path integration part

42, 98 Light source control part 43 Blue LED
48 Long cut filter (LCF)
55 light guide 56 imaging device 95 mode switching unit 96 mode switching button 97 long cut filter (LCF) moving mechanism 115 purple semiconductor light source

Claims

A blue light source emitting blue light in a blue wavelength band,
Of the blue light, in the reflection spectrum of the superficial blood vessels present in the surface layer of the mucous membrane of the living tissue and the middle layer blood vessels present in the middle layer among the blue light, the intersection of the reflectivity of the surface blood vessel and the middle layer blood vessel A long cut filter that cuts at least a part of long wavelength components longer than
An endoscope system characterized by having.
The endoscope system according to claim 1, wherein the wavelength of the intersection is a value in the range of 445 nm to 460 nm.
The endoscope system according to claim 2, wherein the 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 that emits green light in a green wavelength band;
A red semiconductor light source that emits red light in a red wavelength band;
The endoscope system according to claim 4 or 5, further comprising an optical path integration unit that integrates the optical paths of the respective color lights emitted by 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 respective colors simultaneously.
A surface blood vessel emphasis observation mode in which the cut function of the long cut filter is activated to emphasize and observe the surface blood vessels;
The endoscope system according to any one of claims 1 to 7, further comprising: a mode switching unit configured to switch the mode to a normal observation mode in which the observation function is observed by disabling the cutting function.
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 disposed on the optical path of the blue light and a retracted position retracted 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 accordance with an instruction signal from the operation member.
It has a purple semiconductor light source that emits purple light of a purple wavelength band for emphasizing and observing an extreme surface blood vessel closer to the mucosal surface layer among the surface blood vessels present in the mucosal surface layer of a living tissue. The endoscope system according to any one of to 9.
An imaging element that captures an image of an observation target illuminated by illumination light including long-cut blue light from which at least a part of long wavelength components of the intersection or more is cut, and outputs an image signal;
The endoscope system according to any one of claims 1 to 10, further comprising: an emphasizing processing unit for emphasizing the surface blood vessel with respect to the image signal.