JP2020018914A - Endoscope system - Google Patents

Abstract

To provide an endoscope system that obtains an observation image by further enhancing the contrast of a superficial blood vessel to further finely observe the superficial blood vessel.SOLUTION: An endoscope system integrates light emitted by multiple semiconductor light sources, as illumination light. The endoscope system includes: a long cut filter 48; and a mode switching unit 95 for switching the mode between a normal observation mode of disabling a cut function of the long cut filter 48 and a superficial blood vessel enhancing observation mode of enabling the cut function of the long cut filter 48. Illumination light includes green light and specific blue light. Green light and specific blue light are continuous in terms of their spectra.SELECTED DRAWING: Figure 21

Description

  The present invention relates to an endoscope system.

  In the medical field, endoscope diagnosis using an endoscope system has become widespread. An endoscope system includes an endoscope, an endoscope light source device (hereinafter, simply referred to as a light source device) that supplies illumination light to the endoscope, and a processor device that processes an image signal output by the endoscope. It has. The endoscope has an insertion portion to be inserted into a living body. An illumination window for irradiating the observation site (subject) with illumination light and an observation window for photographing the observation site are arranged at the distal end of the insertion section. The endoscope has a built-in light guide composed 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 arranged behind 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 by the imaging device. The observation image is displayed on the monitor, and the observation inside the living body is performed.

  In recent endoscope diagnosis, special light (narrow band light) limited to a specific wavelength band is used in contrast to the conventional observation that grasps the overall properties of the surface of living tissue under white light. The observations used are also being actively conducted. There are various types of observations using special light.However, by utilizing the optical property that the depth of light penetration into living tissue varies depending on the wavelength, blood vessels existing in the mucous membrane of living tissue are highlighted and displayed. Known blood vessel enhanced observation is known (see Patent Documents 1 and 2). In abnormal tissues such as cancers occurring in living tissues, the state of blood vessels is different from that in normal tissues, and thus, the blood vessel enhanced observation has been recognized as useful for early cancer detection and the like.

  The light source devices described in Patent Documents 1 and 2 include, in addition to a light source that emits white light, a blue semiconductor that emits, for example, a narrow band blue light having a center wavelength of about 445 nm, which is well absorbed by a surface blood vessel existing on the mucosal surface. A light source is provided as a light source for special light. By illuminating each of these light sources and simultaneously irradiating the observation site with white light and blue light, and imaging the reflected light with an image sensor, an observation image in which surface blood vessels are emphasized is obtained. In Patent Literatures 1 and 2, in order to obtain an observation image in which surface blood vessels are enhanced, a process of enhancing surface blood vessels is performed on an image signal output from an image sensor.

JP 2011-098088 A JP 2012-152449 A

  By the way, the present inventors have found the relationship between the reflection spectra of the mucous membrane, the superficial blood vessels, and the middle blood vessels 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 a superficial blood vessel is indicated by a solid line, and the reflection spectrum of a middle blood vessel is indicated by a dotted line. The superficial blood vessels are typically 10 μm thick blood vessels at a depth of 10 μm from the mucosal surface, and the middle blood vessels are typically 10 μm to 20 μm thick blood vessels at a depth of 50 μm from the mucosal surface. Is shown.

  The reflectance of the superficial blood vessels is greatly reduced in a wavelength band below 450 nm, and the difference from the reflectance of the middle blood vessels and the mucous membrane is large. On the other hand, the reflectance of the middle 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 the mucous membrane is large. The reflectance of the mucous membrane is higher than the reflectance of the surface blood vessels and the middle blood vessels in all wavelength bands.

  Focusing on the change in the reflectance of the superficial blood vessels and the middle blood vessels, the reflectivity of the superficial blood vessels is lower than that of the middle blood vessels in the wavelength band lower than 450 nm, and the reflectance of the superficial blood vessels and the middle blood vessels becomes the same around 450 nm. In the above wavelength band, the magnitude of the reflectance is reversed, and the reflectance of the middle blood vessel is lower than that of the surface blood vessel. In other words, when irradiating light in a wavelength band lower than 450 nm, the surface blood vessels absorb light better and are emphasized on the observation image, and when irradiating light in a wavelength band of 450 nm or more, conversely, the middle blood vessels are more illuminated than the surface blood vessels. This is emphasized on the observation image. For this reason, when the superficial blood vessels are to be observed, the difference between the superficial blood vessels and the middle blood vessels is smaller when the light component in the wavelength band of 450 nm or more, which is the intersection of the reflectance of the superficial blood vessels and the middle blood vessels, indicated by the symbol P is smaller. It is clear that a clearly distinguished high-contrast observation image can be obtained.

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

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

  The present invention provides an endoscope system using integrated illumination light emitted from a plurality of semiconductor light sources, a long cut filter, a normal observation mode for disabling a cut function of the long cut filter, and a long cut filter. A mode switching unit that switches between a superficial blood vessel emphasis observation mode that enables a cut function, and the illumination light includes green light and a specific blue light, and the spectrum of the green light and the specific blue light is continuous. It is.

  The present invention provides an endoscope system using integrated illumination light emitted from a plurality of semiconductor light sources, a long cut filter, a normal observation mode for disabling a cut function of the long cut filter, and a long cut filter. A mode switching unit that switches between a superficial blood vessel enhancement observation mode that enables a cut function, and green light, specific blue light, and purple light are included in the illumination light, and the green light and the specific blue light are spectrally separated. Is continuous.

  It is preferable that the wavelength band of the specific blue light is narrower than the wavelength band of the green light. It is preferable that the specific blue light is a long cut blue light cut out from the blue light by a long cut filter. The long cut filter is a long-wavelength component of the blue light, in the reflection spectrum of the surface blood vessels present in the mucosal surface layer of the living tissue and the middle blood vessels present in the middle layer, of the wavelength at the intersection of the reflectance of the surface blood vessels and the middle blood vessels. It is preferable to obtain at least a long-cut blue light by cutting at least a part of the long-wavelength component where the reflectance of the middle blood vessel becomes smaller than the reflectance of the surface blood vessel. It is preferable that the intersection of the reflectance between the surface blood vessel and the middle blood vessel shifts to the longer wavelength side as the thickness of the surface blood vessel increases.

  The blue light is preferably emitted from a blue semiconductor light source. It is preferable that the mode switching unit has a long cut filter moving mechanism that slides the long cut filter between a set position disposed on the front surface of the blue semiconductor light source and a retracted position retracted from the front surface of the blue semiconductor light source. In the blue light, it is preferable that the wavelength width of the wavelength component equal to or larger than the half width of the light intensity is narrower than the wavelength width of the wavelength component equal to or smaller than the half width. Preferably, the green light and the blue light are integrated by an optical path integration unit.

  The violet light is preferably emitted from a violet semiconductor light source. It is preferable that the wavelength width of the wavelength component of the violet light whose wavelength is equal to or greater than the half width of the light intensity is narrower than the wavelength width of the wavelength component whose wavelength is equal to or less than the half width. The green light, the blue light, and the violet light are preferably integrated by an optical path integration unit. Preferably, the illumination light includes red light.

  ADVANTAGE OF THE INVENTION According to this invention, the observation image which made the contrast of a surface blood vessel stand out more can be obtained, and a superficial blood vessel can be observed more finely.

It is an outline view of an endoscope system of the present invention. FIG. 2 is a front view of a distal end portion of the endoscope. FIG. 2 is a block diagram illustrating an electrical configuration of the endoscope system. It is a figure showing a blue semiconductor light source. 5 is a graph showing an emission spectrum of blue light emitted from a blue semiconductor light source. 5 is a graph showing an emission spectrum of green light emitted from a green semiconductor light source. 4 is a graph showing an emission spectrum of red light emitted from a red semiconductor light source. 5 is a graph showing transmission characteristics 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 light emission spectrum of illumination light comprised by long cut blue light, green light, and red light. 5 is a graph illustrating spectral characteristics of a micro color filter of an imaging device. FIG. 3 is an explanatory diagram illustrating irradiation timing of illumination light and operation timing of an image sensor. It is a figure showing a surface layer blood vessel and a middle layer blood vessel drawn on B picture. It is a figure showing a surface blood vessel and a middle blood vessel drawn on a G picture. FIG. 3 is a diagram illustrating an arrangement of each semiconductor light source and a detailed configuration of an optical path integration unit. 9 is a graph showing transmission characteristics of a dichroic filter of a dichroic mirror integrating light paths of green light and red light. 5 is a graph showing transmission characteristics of a dichroic filter of a dichroic mirror integrating optical paths of blue light, green light, and red light. It is a graph which shows the transmission characteristic of the 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. 19 is a graph showing an emission spectrum of long-cut blue light in the example of FIG. 19 is a graph showing an emission spectrum of illumination light composed of long-cut blue light, green light, and red light in the example of FIG. 18. It is a figure showing a light source device of a 2nd embodiment provided with a mode switching part. It is a graph which shows the light emission spectrum of the illumination light comprised by blue light, green light, and red light. It is a figure showing the light source device of a 3rd embodiment provided with a purple semiconductor light source. 4 is a graph showing an emission spectrum of violet light emitted from a violet semiconductor light source. It is a graph which shows the light emission spectrum of illumination light comprised by long cut blue light, green light, red light, and violet light. 6 is a graph showing transmission characteristics of a dichroic filter of a dichroic mirror integrating optical paths of blue light and violet light. 4 is a graph showing a scattering coefficient of a living tissue. FIG. 3 is an explanatory diagram showing irradiation timing of illumination light and operation timing of an imaging element in an enhanced observation of a very superficial blood vessel. It is a graph which shows the reflection spectrum of a mucous membrane, a superficial blood vessel, and a middle 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 the imaging, and an observation site. A light source device 13 for supplying illumination light for irradiating the endoscope 11 to the endoscope 11 and a monitor 14 for displaying an observation image are provided. An operation input unit 15 such as a keyboard and a mouse is connected to the processor device 12.

  The endoscope 11 connects the insertion section 16 to be inserted into the digestive tract of a living body, the operation section 17 provided at a base end portion of the insertion section 16, and connects the endoscope 11, the processor device 12, and the light source device 13. 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 sequentially provided from the distal end. As shown in FIG. 2, an illumination window 22 for irradiating illumination light to an observation site, an observation window 23 for capturing an image of the observation site, and an air supply for cleaning the observation window 23 are provided on the distal end surface of the distal end portion 19. An air supply / water supply nozzle 24 for supplying water and a forceps outlet 25 for projecting a treatment tool such as a forceps or an electric scalpel to perform various treatments are provided. An imaging element 56 and an objective optical system 60 for imaging (both shown in FIG. 3) are built in the back of the observation window 23.

  The bending section 20 is composed of a plurality of connected bending pieces, and performs a bending operation in the vertical and horizontal directions by operating the angle knob 26 of the operation section 17. By bending the bending portion 20, the direction of the distal end portion 19 is directed to a desired direction. The flexible tube portion 21 has flexibility so that it can be inserted into a winding tube such as an esophagus or an intestine. The insertion section 16 includes a communication cable for communicating a drive signal for driving the image sensor 56 and an image signal output by the image sensor 56, and a light guide 55 (see FIG. 4) for guiding illumination light supplied from the light source device 13 to the illumination window 22. (See FIG. 3).

  The operation unit 17 includes, in addition to the amble knob 26, a forceps port 27 for inserting a treatment tool, an air supply / water supply button 28 operated when performing air supply / water supply from the air supply / water supply nozzle 24, and a still image. A release button (not shown) for photographing and the like are provided.

  A communication cable and a light guide 55 extending from the insertion portion 16 are inserted through 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 including 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. The communication connector 29a is provided with one end of a communication cable, and the light source connector 29b is provided with an incident end 55a (see FIG. 3) of the light guide 55.

  In FIG. 3, a 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 the driving of each of the semiconductor light sources 35 to 37.

  Each of the semiconductor light sources 35 to 37 includes, as semiconductor light emitting elements, 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. , Respectively. Each of the LEDs 43 to 45 is formed by joining a P-type semiconductor and an N-type semiconductor, as is well known. Then, when a voltage is applied, electrons and holes recombine beyond the band gap near the PN junction, causing a current to flow, and upon recombination, energy corresponding to the band gap is emitted as light. Each of the LEDs 43 to 45 increases the amount of emitted light as the value of the supplied power increases.

  As shown in FIG. 4, the blue semiconductor light source 35 includes 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. 35c. The inner surface of the cavity functions as a reflector that reflects light. A diffusing material that diffuses light is dispersed in the resin 35c. The blue LED 43 is conductively connected to the substrate 35a by a wiring 35d. Such a mounting form of the blue semiconductor light source 35 is generally called a surface mount 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 around 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 around 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 around 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. Note that 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 peak wavelength of the emission spectrum of each color light.

  In FIG. 3, a long cut filter (hereinafter abbreviated as LCF) 48 is provided on the front surface of the blue semiconductor light source 35. The LCF 48 is the reflectance of the surface blood vessels and the middle blood vessels in the reflection spectrum of the surface 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 as shown in FIG. Long wavelength components equal to or longer than the wavelength (450 nm) at the intersection point P of FIG. More specifically, as shown in FIG. 8, the LCF 48 has a property of reflecting light in a green or red wavelength band having a wavelength of 450 nm or more and transmitting light in a blue wavelength band less than that. .

  The LCF 48 converts the blue light LB into a long cut blue light LBlc1 shown in FIG. The long-cut blue light LBlc1 is light in which all the light components in the wavelength band of 450 nm or more, which prevent the improvement of the contrast of the surface blood vessels, described with reference to FIG. The long-cut blue light LBlc1 enters the optical path integration unit 41.

  Note that the LCF 48 does not completely cut (ie, cuts 100%) the long wavelength component longer than the wavelength (450 nm) of the intersection P, and the wavelength of the intersection P ( At least a part (for example, 80 to 95%) of a long wavelength component of 450 nm or more is cut. Accordingly, the spectrum of the long-cut blue light LBlc1 is not discrete but 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 the turning on / off of the LEDs 43 to 45 and the amount of light via 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 light each of the LEDs 43 to 45 by continuously applying a drive current to each of the LEDs 43 to 45. Then, the supply power to each of the LEDs 43 to 45 is changed by changing the drive current value to be given in accordance with the exposure control signal received from the processor device 12, and the light amounts of the blue light LB, the green light LG, and the red light LR are changed. Each is controlled independently. It should be noted that the drive current is not applied continuously but in the form of a pulse, and PAM (Pulse Amplitude Modulation) control for changing the amplitude of the drive current pulse or PWM (Pulse Width Modulation) control for changing 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 unit of the optical path integrating unit 41 is arranged near the receptacle connector 54 to which the light source connector 29b is connected. The light path integrating unit 41 emits light incident from each of the semiconductor light sources 35 to 37 to an incident end 55 a of a light guide 55 of the endoscope 11. Although not shown, the light source connector 29b and the receptacle connector 54 are provided with protective glass, respectively.

  FIG. 10 shows 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. 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 a desired observation image. Specifically, the ratio of the light amounts of the long-cut blue light LBlc1, the green light LG, and the 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 the target emission spectrum. . Here, as described above, the long cut blue light LBlc1 and the green light LG have continuous spectra, and further, 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 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 controls exposure of illumination light while maintaining a target emission spectrum. When the ratio of the light amount of each color light constituting the illumination light changes, the emission spectrum of the illumination light changes and the color of the observed image changes. For this reason, 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 light amount 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 element 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 29b is connected to the light source device 13, the incident end 55a of the light guide 55 disposed on the light source connector 29b faces the light emitting part of the optical path integrating unit 41. The exit end of the light guide 55 located at the distal end portion 19 is branched into two in front of the illumination windows 22 so that light is guided to the two illumination windows 22.

  An illumination lens 59 is arranged behind the illumination window 22. The illumination light supplied from the light source device 13 is guided to the illumination lens 59 by the light guide 55 and is emitted from the illumination window 22 toward the observation site. The irradiation lens 59 is formed of a concave lens, and widens the divergence angle of light emitted from the light guide 55. This makes it possible to irradiate the illumination light over a wide range of the observation site.

  An objective optical system 60 and an image sensor 56 are arranged behind the observation window 23. The image of the observation site enters the objective optical system 60 through the observation window 23, and is formed on the imaging surface 56a of the imaging element 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 an imaging surface 56a. The imaging element 56 photoelectrically converts the light received on 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. 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 an analog image signal from the image sensor 56, and removes noise caused by resetting signal charges. 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 a 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 a drive signal from the imaging control unit 58.

  The image sensor 56 is a color image sensor, and the image pickup surface 56a is provided with three color filters of B, G, and R 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 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 that constitute the illumination light LW1 are mainly B pixels that are reflected light corresponding to the long cut blue light LBlc1, G pixels that are mainly reflected light corresponding to the green light LG, and red. The reflected light corresponding to the light LR is mainly received by each of the R pixels.

  As shown in FIG. 12, the image sensor 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 in accordance with the timing of the accumulation operation of the imaging element 56, and the illumination light LW1 (LBlc1 + LG + LR) composed of a mixed light of the long-cut blue light LBlc1, the green light LG, and the red light LR is applied to the observation site. Irradiated, the reflected light is incident on the image sensor 56. The image sensor 56 separates the reflected light of the illumination light LW1 by using a micro color filter. The B pixel receives the reflected light corresponding to the long cut blue light LBlc1, the G pixel receives the reflected light corresponding to the green light LG, and the R pixel receives the 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 the B, G, and R pixels are mixed in accordance with the frame rate in accordance with the readout timing.

  In FIG. 3, the processor device 12 includes a controller 65, a DSP (Digital Signal Processor) 66, an image processing unit 67, a frame memory 68, and a display control circuit 69. The controller 65 has a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a control program and setting data necessary for control, a RAM (Random Access Memory) that loads a program and functions as a working memory, and the like. The CPU controls each unit of the processor device 12 by executing the 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 a pixel interpolation process on the image signal of each color. Thereby, 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 each of the B, G, and R image signals.

  The DSP 66 calculates an 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 by the DSP 66 and processed image data processed by the image processing unit 67. The display control circuit 69 reads out the image-processed image data 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 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 each time the image signals B, G, and R in the frame memory 68 are updated. The image signal B includes a reflected light component corresponding to the long-cut blue light LBlc1 included in the illumination light LW1. As described above, since the long-cut blue light LBlc1 is light in which all light components in a wavelength band of 450 nm or more that hinder improvement in contrast of the surface blood vessels are cut off, the surface blood vessels are drawn with high contrast. In lesions such as cancer, since the pattern of the blood vessels is characteristic, for example, the density of superficial blood vessels tends to be higher than that of normal tissues, the observation of superficial vascular Is preferably drawn clearly.

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

  Here, in the image 71 represented by the image signal B of each pixel (hereinafter, referred to as a B image) 71, as shown by a thick line and a thin hatching in FIG. As shown by only the figure, the middle blood vessel 73 is also slightly reflected. This is because the middle blood vessels also absorb light in the wavelength band below 450 nm at all. However, the reflection of the middle blood vessel 73 in the B image 71 is less than that in the case where the light in the wavelength band of 450 nm or more is irradiated. On the other hand, in the image (hereinafter, referred to as G image) 74 represented by the image signal G of each pixel, as shown by a thick line and light hatching in FIG. Is rendered. The surface blood vessels 72 are also slightly reflected as shown by the thin lines only. Since the image signal G includes a reflected light component corresponding to the green light LG in the wavelength band of 530 nm to 560 nm in which the absorption of the middle blood vessel 73 is larger than that of the surface blood vessel 72, the G image 74 is emphasized. Becomes a middle-layer blood vessel 73 opposite to the B image 71.

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

  In FIG. 15, an optical path integrating unit 41 includes collimator lenses 80, 81, and 82 for collimating the respective color lights emitted from the semiconductor light sources 35 to 37, dichroic mirrors 83 and 84, and a light guide for emitting light from the optical path integrating unit 41. And a condensing lens 85 for condensing the light at the incident end 55a. 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 so as 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 arranged 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 at 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 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 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 to the downstream side, and reflects the red light LR incident from the red semiconductor light source 37 via the collimator lens 82. Thereby, the light 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. 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 via the LCF 48 and the collimator lens 80. The dichroic mirror 84 integrates all optical paths of the long-cut blue light LBlc1, the green light LG, and the red light LR, and generates the illumination light LW1.

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

  The insertion section 16 of the endoscope 11 is inserted into the digestive tract of the subject, and observation inside the digestive tract is started. The light source control unit 42 sets a drive current value to be given to each of the LEDs 43 to 45 and starts lighting of each of the semiconductor light sources 35 to 37. Then, light amount control is performed while maintaining a target emission spectrum.

  The semiconductor light sources 35 to 37 emit blue light LB, green light LG, and red light LR from 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 LBlc1, the green light LG, and the red light LR enter 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 has a wavelength component around 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 draw the surface blood vessel with high contrast. You had better. Therefore, in the present embodiment, the LCF 48 cuts long wavelength components of 450 nm or more so as to prevent deterioration of the contrast of the surface blood vessels.

  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. 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 LBlc1, green light LG, and red light LR enter the condenser 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 condenser 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 emitted from the illumination window 22 to the observation site. The reflected light of the illumination light LW <b> 1 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 into colors and inputs the color-separated signals to the image processing unit 67. The imaging operation by the imaging element 56 is repeated at a predetermined frame rate.

  The emphasis processing unit 70 performs a process of emphasizing 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 that have been 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 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. 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 such that the ratio of the light amount of each color light becomes constant (the target emission spectrum does not change). . Then, each of the semiconductor light sources 35 to 37 is driven by the determined drive current value. Accordingly, the light amounts of the long-cut blue light LBlc1, green light LG, and 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 amounts of the blue light LB, the green light LG, and the red light LR can be controlled independently of each other, it is easy to generate the illumination light LW1 having the target emission spectrum, and while maintaining the target emission spectrum. 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 include any component that deteriorates the contrast of the superficial blood vessels on the observation image. The emphasis processing unit 70 performs a process of emphasizing the surface blood vessels. Conventionally, only the process of emphasizing the surface blood vessels was performed. In the present invention, in addition to this, the light component that deteriorates the contrast of the surface blood vessels on the observed image is removed by the LCF 48. For this reason, it is possible to obtain an observation image suitable for finer observation of the surface blood vessels, in which the difference between the surface blood vessels and the middle blood vessels 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 illustrated in the first embodiment, but may be on the optical path of the blue light LB. For example, the LCF 48 may be arranged between the collimator lens 80 and the dichroic mirror 84.

  The LCF 48 may have, for example, a bandpass 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 higher manufacturing cost than 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 aspect.

  The wavelength of the intersection point P of the reflectance between 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, as exemplified in the first embodiment, but depends on the thickness of the surface blood vessel to be observed. As the thickness of the surface blood vessels increases, the wavelength of the intersection P also 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. Therefore, the wavelength to be 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 point 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 less than that, as shown in FIG. Is used. The LCF 48 having the transmission characteristics shown in FIG. 18 turns the blue light LB into the long-cut blue light LBlc2 shown in FIG. The long-cut blue light LBlc1 shown in FIG. 9 does not include a light component having a peak wavelength of 455 nm of the blue light LB, but the long-cut blue light LBlc2 includes a light component having a peak wavelength of 455 nm of the blue light LB. ing. Therefore, the long cut blue light LBlc2 has a larger light amount 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 optical path integration unit 41 is as shown in FIG. Note that the spectrum of the illumination light LW2 is continuous over the entire wavelength band, similarly to the illumination light LW1.

  The processing for enhancing the surface blood vessels is described in Japanese Patent Application Laid-Open No. 2011-098088 of Patent Document 1 and Japanese Patent Application Laid-Open No. 2012-152559 of Patent Document 2 in addition to the method exemplified in the first embodiment. May be adopted. For example, since the surface blood vessels appear relatively thin on the observation image, the frequency component is biased toward a relatively high frequency, and the frequency filtering is performed on the B image 71 to extract the high frequency components corresponding to the surface blood vessels. The contrast of the surface blood vessels is increased by enhancing the surface blood vessels in the B image 71 with the extracted high frequency components. Alternatively, a middle-low frequency component corresponding to the middle-layer blood vessel is extracted, 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 emphasis processing, the processing for enhancing the surface blood vessels may be any processing that widens the contrast difference between the surface blood vessels and the middle blood vessels, and increases the contrast of the surface blood vessels with respect to the middle blood vessels. Not limited to the processing, nothing is performed on the superficial blood vessels; instead, the processing of suppressing the contrast of the superficial blood vessels and increasing the contrast of superficial blood vessels relatively, and increasing the contrast of superficial blood vessels and the contrast of the superficial blood vessels 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 cut function of the LCF 48 is always enabled. However, the present invention is not limited to this. The enable / disable of the cut function of the LCF 48 may be switched.

  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 enhances the superficial blood vessel observation mode by emphasizing the superficial blood vessels, and disables the cut function of the LCF 48 and observes the general properties of the observation site. Switch between modes. The light source device 90 has the same configuration as that of the first embodiment except that a mode switching unit 95 is provided. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. I 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 mode switching button 96 is a front panel of the housing of the light source device 90 or the processor device 12, or the operation unit 17 of the endoscope 11. Etc. are provided. The light source control unit 98 controls the turning on / off of the LEDs 43 to 45 and the light amount via the drivers 50 to 52 as well as the light source control unit 42 of the first embodiment. The driving of the LCF moving mechanism 97 is controlled according to the instruction signal.

  The LCF moving mechanism 97 includes, for example, a motor and a rack-and-pinion gear (both not shown) for changing 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 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 becomes a long cut blue light LBlc1 by cutting a long wavelength component of 450 nm or more, as in the first embodiment. The observation site is irradiated with illumination light LW1 that is a mixed light of the long-cut blue light LBlc1, the green light LG, and the red light LR. 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 directly enters the optical path integration unit 41. 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 that of white light emitted when observing the entire properties of the conventional observation site. Unlike the illumination light LW1, the illumination light LW0 is not subjected to processing for improving the contrast of the superficial blood vessels in the blue light LB unlike the illumination light LW1, and therefore is more suitable for observing the overall properties of the observation region than the illumination light LW1. . Further, since the light component of the blue light LB is not cut, the light amount is larger than that of the illumination light LW1.

  As described above, if the mode switching unit 95 is provided to enable the operator to select whether to enable or disable the cut function of the LCF 48, the overall property of the observation region using white light, which has been conventionally performed, can be obtained. Both observation (normal observation mode) and enhancement observation of surface blood vessels (surface blood vessel enhancement observation mode) can be performed. In the initial stage of observation, the normal observation mode can be selected to observe the overall properties of the observation site, and when an observation site suspected of a lesion is found, the superficial blood vessel enhanced observation mode can be selected. Further, when observing the overall 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. It is more advantageous to use LW0.

  Since the emission spectrum of the illumination light is different between the normal observation mode and the superficial blood vessel emphasis observation mode, the signal processing such as the white balance correction performed by the DSP 66 is performed, for example, so that 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 above-described motor and the rack and pinion gear. For example, an LCF 48 is formed on a half surface of a disk (turret) made of visible light transmitting glass, and the other half is not provided, so that blue light LB can be transmitted as it is, and the disk is rotated by a motor. By doing so, the cut function of the LCF 48 may be enabled or disabled.

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

  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, the surface spacing of a substrate composed of two high-reflection optical filters is changed, and thereby an etalon filter that controls the wavelength band of transmitted light, and birefringence between polarizing filters. A filter having variable transmission characteristics, 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 having 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 having 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 transmitted light by driving the etalon filter or the liquid crystal tunable filter. And a control unit that controls the 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 constituted by the three semiconductor light sources 35 to 37 of blue, green and red. Hereinafter, a violet semiconductor light source that emits light in a violet wavelength band for emphasizing and observing the superficial blood vessels to be distinguished from the superficial blood vessels to be observed in the above embodiments may be added.

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

  The violet semiconductor light source 115 has a violet LED (not shown) that emits light in a violet wavelength band as a light emitting element. 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 around 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 integrating unit 117 is configured by adding a collimator lens 118 for collimating the violet light LV, a long cut blue light LBlc1, and a dichroic mirror 119 for integrating the optical path of the violet light LV to the optical path integrating unit 41 of each of the above embodiments. It is. The optical path integrating 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 the 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 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 arranged at an angle of 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 violet wavelength band of less than about 430 nm and transmitting light in the blue, green, and red wavelength bands. I have. The dichroic mirror 119 transmits the long-cut blue light LBlc1 incident via the collimator lens 80 to the downstream side, and reflects the violet light LV incident from the violet semiconductor light source 38 via the collimator lens 118. Thus, the optical paths of the long-cut blue light LBlc1 and the violet light LV are integrated. The violet light LV reflected by the dichroic mirror 119 is reflected by the dichroic mirror 84 and reflected by the condensing lens 85 because the dichroic mirror 84 has a characteristic of reflecting 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 violet light LV are integrated.

  In FIG. 29, the reflectance of the superficial blood vessels drops significantly in the wavelength band below 450 nm, and drops most around 405 nm. When light in a wavelength band having a low reflectance is applied to the observation site, an observation image having a difference in contrast between the blood vessel and other portions is obtained because the absorption is large in the blood vessel.

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

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

  In FIG. 28, when the extreme surface blood vessels are to be emphasized, the violet 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 image sensor 56. When the semiconductor light sources 35 to 37 and 115 are turned on, the violet light LV is added together with the illumination light LW1, and the illumination light LW3 shown in FIG. 25, which is a mixture of these lights (LW1 + LV), is emitted to the observation site.

  The illumination light LW3 obtained by adding the violet 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 violet light LV in addition to the reflected light corresponding to the long cut blue light LBlc1. The G pixel and the R pixel receive the reflected light corresponding to the green light LG and the reflected light corresponding to the red light LR, respectively, as in the first embodiment. 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 the reflected light component corresponding to the violet light LV in addition to the reflected light component corresponding to the long cut blue light LBlc1 included in the illumination light LW1. In addition, very superficial blood vessels are depicted with high contrast. Like the superficial blood vessels, in a lesion such as a cancer, the pattern of the superficial blood vessels is characteristic, such as a tendency that the density of the superficial blood vessels tends to be higher than that of normal tissue. According to 110, the very superficial blood vessels are clearly depicted, which is preferable.

  In the first embodiment, the light amount control of each color light is performed by changing the drive current value given to each of the LEDs 43 to 45 based on the exposure control signal from the processor device 12. Due to the influence of aging, the output light amount of the semiconductor light source with respect to the drive current value may fluctuate. Therefore, a light quantity measurement sensor for measuring the light quantity of each color light may be provided, and whether or not the light quantity of each color light has reached a target value may be monitored 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 amount measurement signal with the target light amount, and gives the light amount to each of the semiconductor light sources 35 to 37 set by the exposure control based on the comparison result so that the light amount becomes the target value. Fine-adjust the drive current value. As described above, the light amount of each color light is constantly monitored by the light amount measurement sensor, and the drive current value given based on the measurement result of the light amount is finely adjusted, so that the light amount can always be controlled so as to be in line with the target value. Therefore, illumination light of a target emission spectrum can be more stably obtained.

  In each of the above embodiments, the semiconductor light source including only the LED is described. For example, a green semiconductor light source is excited by a blue excitation light LED that emits blue excitation light in a violet to blue wavelength band, and a blue excitation light. The fluorescent semiconductor light source may be configured by a green phosphor that emits green light in a green wavelength band. In addition, instead of or in addition to the green semiconductor light source, a red semiconductor light source is provided with a blue excitation light LED emitting blue excitation light in a violet to blue wavelength band, and a red fluorescent light in a red wavelength band excited by blue excitation light. May be constituted by a red phosphor that emits light. When the red semiconductor light source is configured by 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 a green light that emits green excitation light in a green wavelength band. An excitation light emitting element may be used. In this case, a fluorescent material is sealed in the cavity of the mold 35b of the first embodiment shown in FIG. 4 instead of the resin 35c to form a fluorescent semiconductor light source.

  When the light emitted from the excitation light emitting element of the fluorescent semiconductor light source includes a component that is equal to or greater than the wavelength of the intersection P of the reflectance of the surface blood vessel and the middle blood vessel, it is preferable to provide a filter that cuts off the light component.

  The mounting form of the LED shown in FIG. 4 is one example, and another form may be adopted. For example, a microlens for adjusting the divergence angle may be provided on the light emitting surface of the sealing resin 35c, or a form in which the LED is housed in a shell type case in which the microlens is formed instead of the surface mount type. . Further, when a fluorescent semiconductor light source is used as the green semiconductor light source or the 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 provided integrally, but may be those in which these are 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 via the light guide member.

  Furthermore, a laser diode (LD (Laser Diode)) may be used instead of the LED as the fluorescent semiconductor light emitting element. Organic EL (Electro-Luminescence) elements may be used in addition to LEDs and LDs. Not limited to the fluorescent semiconductor light source, an LD or an organic EL element may be used as a light emitting element of another semiconductor light source.

  As a configuration of the light source unit, a combination of a white light source and a blue semiconductor light source may be used instead of the light source units having the blue, green, and red semiconductor light sources 35 to 37 illustrated in the above embodiments. As a white light source, a white LED or a fluorescent white semiconductor light source composed of a blue excitation light emitting element and a phosphor excited by the blue excitation light and emitting fluorescence in a broad wavelength band from green to red using a white LED or the like. Alternatively, a xenon lamp or a metal halide lamp may be used instead of the semiconductor light source.

  Further, the light source unit may be configured by a white light source and a filter turret arranged on an optical path of white light emitted from the white light source. The filter turret has an LCF 48 formed on a half surface of a disk made of visible light transmitting glass, and the other half is not provided with anything, and transmits the white light emitted by the white light source as it is, and is rotated by a motor or the like. . The LCF 48 generates a long-cut blue light by cutting a light component of the white light having a wavelength equal to or more than the wavelength of the intersection P of the reflectance of the surface blood vessel and the middle blood vessel. 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 irradiated with white light and long-cut blue light alternately 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 emphasis processing unit 70 emphasizes surface 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 also serves as the blue light source, it is difficult to independently control the light amount of the blue light. Therefore, as in the above embodiments, the blue light source is used as a single blue semiconductor light source, and the light amount of the blue light is controlled independently. It is more preferable to make the configuration controllable. In addition, by using the blue light source as a single blue semiconductor light source, compared to the case where the white light source also serves as the blue light source, the amount of blue light LB and thus the long cut blue light can be obtained, and the visibility of the surface blood vessels is improved. It is more preferable because it can be performed.

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

  The observation site may be irradiated with the mixed light of the long-cut blue light and the green light LG or the mixed light of the green light LG and the violet light LV to obtain the observation image based on the green light LG.

  In each of the above embodiments, the image sensor 56 includes a color image sensor that separates the illumination light by the B, G, and R micro color filters, and simultaneously obtains the B, G, and R image signals by the color image sensor. The simultaneous endoscope system and the light source device used therein have been described as an example. However, the monochrome endoscope system has a monochrome image sensor, and sequentially irradiates blue, green, and red light, and outputs B, G, and R image signals. The present invention may be applied to a frame-sequential type endoscope system obtained in a frame-sequential manner and a light source device used therein.

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

  In each of the embodiments described above, an example has been described in which the light source device and the processor device are configured separately, but the two devices may be configured integrally. Further, the present invention provides 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 imaging element and an ultrasonic transducer are incorporated in a distal end portion. Also, the present invention can be applied to a light source device used therein.

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 section 96 mode switching button 97 long cut filter (LCF) moving mechanism 115 purple semiconductor light source

Claims (14)

In an endoscope system using illumination light in which light emitted by a plurality of semiconductor light sources is integrated,
A long cut filter,
A normal observation mode that disables the cut function of the long cut filter, and a mode switching unit that switches between a surface blood vessel enhancement observation mode that enables the cut function of the long cut filter,
The illumination light includes a green light and a specific blue light,
An endoscope system wherein the green light and the specific blue light have continuous spectra. In an endoscope system using illumination light in which light emitted by a plurality of semiconductor light sources is integrated,
A long cut filter,
A normal observation mode that disables the cut function of the long cut filter, and a mode switching unit that switches between a surface blood vessel enhancement observation mode that enables the cut function of the long cut filter,
The illumination light includes green light, specific blue light, and violet light,
An endoscope system wherein the green light and the specific blue light have continuous spectra.   The endoscope system according to claim 1, wherein a wavelength band of the specific blue light is narrower than a wavelength band of the green light.   4. The endoscope system according to claim 1, wherein the specific blue light is a long-cut blue light cut out from the blue light by the long-cut filter. 5.   The long cut filter, in the blue light, 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, the wavelength of the wavelength of the intersection of the reflectance of the surface blood vessels and the middle layer blood vessels or more 5. The endoscope system according to claim 4, wherein a long-cut blue light is obtained by cutting at least a part of the long-wavelength component that is a long-wavelength component and the reflectance of the middle blood vessel is smaller than the reflectance of the superficial blood vessel.   6. The endoscope system according to claim 5, wherein the intersection of the reflectance of the surface blood vessel and the reflectance of the middle blood vessel shifts to a longer wavelength side as the thickness of the surface blood vessel increases.   The endoscope system according to any one of claims 4 to 6, wherein the blue light is emitted from a blue semiconductor light source.   The mode switching unit has a long cut filter moving mechanism that slides the long cut filter between a set position disposed on the front surface of the blue semiconductor light source and a retracted position retracted from the front surface of the blue semiconductor light source. The endoscope system according to claim 7.   9. The endoscope system according to claim 4, wherein a wavelength width of a wavelength component equal to or more than a half width of light intensity of the blue light is narrower than a wavelength width of a wavelength component equal to or less than the half width.   The endoscope system according to any one of claims 4 to 9, wherein the green light and the blue light are integrated by an optical path integration unit.   The endoscope system according to claim 2, wherein the violet light is emitted from a violet semiconductor light source.   The endoscope system according to claim 2, wherein a wavelength width of a wavelength component equal to or greater than a half width of light intensity of the violet light is narrower than a wavelength width of a wavelength component equal to or less than the half width.   The endoscope system according to claim 2, wherein the green light, the blue light, and the violet light are integrated by an optical path integration unit.   14. The endoscope system according to claim 1, wherein the illumination light includes red light.

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