JP2018000994A - Light source device for endoscope and endoscope system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably acquire illumination light with a targeted light-emission spectrum by simple control even when a fluorescent type semiconductor light source is used.SOLUTION: A green semiconductor light source 36 comprises: an excitation light LED 44 for emitting blue excitation light LBe; and a green phosphor 47 excited by the blue excitation light LBe to emit green fluorescence LGf. A dichroic filter of a third dichroic mirror 81 of an optical path integration part 41 serves as an excitation light cut filter which has permeability characteristic for removing at least blue excitation light LBe from the light emission spectrum of the mix light of the blue excitation light LBe and the green fluorescence LGf emitted from the green semiconductor light source 36.SELECTED DRAWING: Figure 18

Description

  The present invention relates to an endoscope light source device that supplies illumination light to an endoscope, and an endoscope system using the same.

  In the medical field, endoscopic diagnosis using an endoscopic system is widespread. 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 that processes an image signal output by the endoscope. Device. The endoscope has an insertion portion that is inserted into a living body, and an illumination window that irradiates the observation site (subject) with illumination light and an observation window that images the observation site are arranged at the tip of the insertion portion. ing. The endoscope has a built-in light guide made of a fiber bundle in which optical fibers are bundled. The light guide guides the illumination light supplied from the light source device to the illumination window. An imaging element such as a CCD is disposed in the back of the observation window. The observation region irradiated with the illumination light is imaged by the imaging device, and a display image for observation is generated by the processor device based on the image signal output from the imaging device. In-vivo observation is performed by displaying the display image on the monitor.

  Conventionally, a xenon lamp or a halogen lamp that emits white light has been used as a light source in a light source device. Recently, however, instead of these, a laser diode (LD) or a light emitting diode (LED: Light Emitting Diode) is used. ) Etc. have been proposed (see Patent Documents 1 and 2).

  Patent Document 1 uses three color semiconductor light sources of blue, green, and red, each composed of three LEDs that emit light of each color of blue (B), green (G), and red (G). A light source device that generates white light by combining three colors of light emitted from an LED is described.

  In the xenon lamp and the halogen lamp, the ratio of the blue component, the green component, and the red component contained in the white light is constant, and the ratio of each color component cannot be changed. On the other hand, the three-color semiconductor light sources of blue, green, and red can independently control the amount of light of each color of blue, green, and red, and the ratio of the amount of light of each color can be freely changed. Multiple types of illumination light having various emission spectra can be easily generated.

  As a green and red semiconductor light source, in addition to a semiconductor light source having a light emitting element that emits light of each color of green and red, an excitation light emitting element that emits excitation light, and either green or red excited by excitation light. There is a fluorescent type semiconductor light source having such a fluorescent substance. For example, the paragraph [0040] of Patent Document 2 includes a blue excitation light LED that emits excitation light in a purple to blue wavelength band and a green phosphor that emits green fluorescence in a green wavelength band by the blue excitation light. A fluorescent green semiconductor light source is described.

  Among LEDs that are currently commercialized, LEDs that emit light in the wavelength band from purple to blue have higher luminous efficiency and are less expensive than LEDs that emit green light. Therefore, a fluorescent green semiconductor light source as described in Patent Document 2 may be used as a green semiconductor light source of the light source device, rather than a semiconductor light source having an LED that emits green light.

JP 2007-068699 A JP 2009-297290 A

  However, for example, when the fluorescent green semiconductor light source described in Patent Document 2 is used as the green semiconductor light source of the light source device of Patent Document 1, there is a problem in that illumination light having a target emission spectrum cannot be stably obtained. Arise. This is because, in the fluorescent green semiconductor light source, most of the blue excitation light is absorbed by the phosphor, but a part of the blue excitation light is not absorbed by the phosphor but passes through the phosphor and is irradiated to the observation site together with the fluorescence. Therefore, changing the amount of green light means that the amount of blue excitation light changes accordingly. Since the wavelength band of the blue excitation light overlaps with the wavelength band of the blue light emitted from the blue semiconductor light source, a change in the amount of green light affects the amount of blue light.

  In endoscopic diagnosis, depending on the purpose of observation, the amount of blue light, green light, and red light may be set to a specific ratio to generate illumination light with a target emission spectrum. On the other hand, the exposure control controls to increase the amount of illumination light when the entire display image is insufficient (underexposure) and to decrease the amount of illumination light when the amount is too high (overexposure) Has been done.

  In exposure control in the case of generating illumination light with a target emission spectrum by determining the ratio of the amount of light of each color light, the overall light amount must be increased or decreased without changing the emission spectrum of the illumination light. However, when a fluorescent semiconductor light source is used, when the output of the fluorescent semiconductor light source is increased and the amount of fluorescent light is changed, the excitation light and the wavelength of the light that overlaps the wavelength band are increased as described above. Since the influence is exerted, the emission spectrum of the illumination light changes. For these reasons, when a fluorescent semiconductor light source is used, illumination light having a target emission spectrum cannot be obtained stably. As a solution to this problem, it is possible to increase or decrease the amount of light that overlaps the excitation light and the wavelength band by taking into account the change in the amount of excitation light that accompanies the change in the amount of fluorescent light. It ’s hard.

  Patent Documents 1 and 2 do not describe the problem that illumination light having a target emission spectrum cannot be stably obtained when a fluorescent semiconductor light source is used, and naturally, a solution is also described. Not.

  The present invention has been made in view of the above problems, and for an endoscope capable of stably obtaining illumination light having a target emission spectrum by simple control even when a fluorescent semiconductor light source is used. An object is to provide a light source device and an endoscope system using the same.

  The present invention relates to an endoscope light source device that supplies illumination light to a light guide of an endoscope, an excitation light emitting element that emits excitation light in a wavelength band at least partially overlapping with the wavelength band of the illumination light, and excitation light A plurality of semiconductor light sources including a fluorescent semiconductor light source having a phosphor that emits fluorescence including at least one of the green or red wavelength bands included in the illumination light, and an excitation light emitting element; An excitation light cut filter for cutting excitation light, an optical path through which the fluorescence emitted by the fluorescent semiconductor light source passes, and a semiconductor light source other than the fluorescent semiconductor light source among a plurality of semiconductor light sources; An optical path integrating optical member that integrates an optical path through which light emitted from the optical path passes is provided.

  It is preferable that the excitation light cut filter is provided in the optical member for optical path integration. A dichroic filter is formed on the optical member for integrating an optical path, and it is preferable that the dichroic filter also serves as an excitation light cut filter. Light emitted from a semiconductor light source other than the fluorescent semiconductor light source preferably overlaps the excitation light and the wavelength band. The excitation light cut filter is preferably provided between the optical path integrating optical member and the fluorescent semiconductor light source.

  The plurality of semiconductor light sources are three semiconductor light sources that emit light in each wavelength band of blue, green, and red, the fluorescent semiconductor light source is at least one of the three semiconductor light sources, and the phosphor is green Or it is preferable to emit either red fluorescence. The fluorescent semiconductor light source is a green semiconductor composed of a blue excitation light emitting element that emits blue excitation light in the purple to blue wavelength band and a green phosphor that emits green fluorescence in the green wavelength band when excited by the blue excitation light. A light source is preferred. Fluorescent semiconductor light sources are excited by blue excitation light emitting elements that emit blue excitation light in the purple to blue wavelength band or green excitation light emitting elements that emit green excitation light in the green wavelength band, and blue excitation light or green excitation light. It is preferable that the red semiconductor light source is composed of a red phosphor that emits red fluorescence in the red wavelength band.

  It is preferable that the plurality of semiconductor light sources further include a purple semiconductor light source that emits light in a purple wavelength band for highlighting the blood vessels on the mucosal surface layer of the living tissue. The excitation light emitting element is preferably a light emitting diode.

  An endoscope system according to the present invention includes an endoscope having a light guide for guiding illumination light, and an endoscope light source device that supplies illumination light to the light guide. A light source device for an excitation light emitting element that emits excitation light in a wavelength band that at least partially overlaps with the wavelength band of illumination light, and a green or red wavelength band that is excited by the excitation light and included in the illumination light Excitation light cut provided on a light path between a plurality of semiconductor light sources having a fluorescent type semiconductor light source having a phosphor emitting fluorescent light including at least one wavelength band, and an excitation light emitting element and a light guide. An optical member for integrating an optical path that integrates a filter, an optical path through which fluorescence emitted from a fluorescent semiconductor light source passes, and an optical path through which light emitted from a semiconductor light source other than the fluorescent semiconductor light source among a plurality of semiconductor light sources passes. Provided.

  According to the present invention, illumination light having a target emission spectrum can be stably obtained by simple control even when a fluorescent semiconductor light source is used.

It is an external view of the endoscope system of the present invention. It is a front view of the front-end | tip part of an endoscope. It is a block diagram which shows the electric constitution of an endoscope system. It is a figure which shows a blue semiconductor light source. It is a figure which shows a green 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 red light which a red semiconductor light source emits. 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 blue excitation light and green fluorescence which a green semiconductor light source emits. It is a graph which shows the absorption spectrum of hemoglobin. It is a graph which shows the scattering coefficient of a biological tissue. It is a graph which shows the emission spectrum of the white light comprised by blue light, green fluorescence, 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 in normal observation mode, and the operation timing of an image pick-up element. It is explanatory drawing which shows the irradiation timing of illumination light in the blood vessel emphasis observation mode, and the operation timing of an image pick-up element. It is explanatory drawing which shows the image processing procedure in normal observation mode. It is explanatory drawing which shows the image processing procedure in blood-vessel emphasis observation mode. 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 a 1st dichroic mirror. It is a graph which shows the transmission characteristic of the dichroic filter of a 2nd dichroic mirror. It is a graph which shows the transmission characteristic of the dichroic filter of a 3rd dichroic mirror. It is a figure which shows the optical path integration part which provided the 1st dichroic mirror in which the dichroic filter which has a function of the excitation light cut filter of 2nd Embodiment was formed. It is a graph which shows the transmission characteristic of the dichroic filter of a 1st dichroic mirror. It is a figure which shows the optical path integration part which provided the excitation light cut filter of 3rd Embodiment. It is a graph which shows the transmission characteristic of an excitation light cut filter. It is a figure which shows the optical path integration part which provided the light quantity measurement sensor of 4th Embodiment. It is a graph which shows the transmission characteristic of the filter arrange | positioned in front of the green light quantity measurement sensor. It is a graph which shows the transmission characteristic of the filter arrange | positioned in front of the red light quantity measurement sensor. It is a block diagram in the case of performing light quantity control using a light quantity measurement sensor. It is a figure which shows the optical path integration part which provided the excitation light cut filter and the light quantity measurement sensor. It is a figure which shows the light source part which provided the white semiconductor light source of 5th Embodiment. It is a figure which shows the other example of the green semiconductor light source of 6th Embodiment. It is a figure which shows the other example of the white semiconductor light source of 6th Embodiment.

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

  The endoscope system 10 includes a normal observation mode for observing an observation site and a blood vessel enhancement observation mode for observing a blood vessel existing inside the mucous membrane of the observation site. The blood vessel enhancement observation mode is a mode for acquiring a blood vessel pattern as blood vessel information and performing a diagnosis such as tumor quality discrimination. In the blood vessel enhancement observation mode, the observation site is irradiated with illumination light containing a large amount of light components in a specific wavelength band having a high absorbance with respect to blood hemoglobin. In the normal observation mode, a normal observation image suitable for observing the entire properties of the observation site is generated as a display image. In the blood vessel enhancement observation mode, a blood vessel enhancement observation image suitable for observing a blood vessel pattern is generated as a display image. The

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

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

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

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

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

  In FIG. 3, the light source device 13 integrates a light source unit 40 including four semiconductor light sources 35, 36, 37, and 38 of blue, green, red, and purple, and an optical path of each color light of each of the semiconductor light sources 35 to 38. And a light source control unit 42 that controls driving of the respective semiconductor light sources 35 to 38.

  The blue, red, and purple semiconductor light sources 35, 37, and 38 are, as light emitting elements, a blue LED 43 that emits light in a blue wavelength band, a red LED 45 that emits light in a red wavelength band, and a purple LED 46 that emits light in a purple wavelength band. Respectively. In contrast, the green semiconductor light source 36 includes a blue excitation light LED (hereinafter simply referred to as excitation light LED) 44 that emits blue excitation light in the purple to blue wavelength band, and green fluorescence in the green wavelength band that is excited by the blue excitation light. A green phosphor 47 emitting

  Each of the LEDs 43 to 46 is formed by joining a P-type semiconductor and an N-type semiconductor as is well known. When a voltage is applied, electrons and holes recombine near the PN junction near the PN junction and a current flows, and energy corresponding to the band gap is emitted as light at the time of recombination. When each LED 43 to 46 increases the value of the supplied power, the amount of emitted light increases. In the green semiconductor light source 36, which is a fluorescent semiconductor light source combining the excitation light LED 44 and the green phosphor 47, the amount of green fluorescence by the green phosphor 47 increases as the amount of blue excitation light from the excitation light LED 44 increases. To do.

  As shown in FIG. 4, the blue semiconductor light source 35 includes a substrate 35a on which a blue LED 43 is mounted, a mold 35b formed on the substrate 35a and having a cavity for accommodating the blue LED 43, and a resin sealed in the cavity. 35c. The inner surface of the cavity functions as a reflector that reflects light. A diffusion material for diffusing light is dispersed in the resin 35c. The blue LED 43 is electrically connected to the substrate 35a by the wiring 35d. Such a mounting form of the blue semiconductor light source 35 is generally called a surface mounting type. Since the semiconductor light sources 35, 37, and 38 except for the green semiconductor light source 36 have basically the same configuration, the blue semiconductor light source 35 will be described as an example, and the description of the red and purple semiconductor light sources 37 and 38 will be omitted. To do.

  As shown in FIG. 5, the green semiconductor light source 36 also has a substrate 36 a and a mold 36 b like the other semiconductor light sources 35, 37 and 38, and the excitation light LED 44 is packaged in a surface mount type. The difference from each semiconductor light source 35, 37, 38 is that a green phosphor 47 is enclosed in the cavity of the mold 36b. The green phosphor 47 is obtained by dispersing a fluorescent substance and a diffusing agent in a sealing resin that seals the excitation light LED 44. Reference numeral 36d denotes a wiring for connecting the substrate 36a and the excitation light LED 44.

  As shown in FIG. 6, the blue LED 43 has, for example, a wavelength component in the vicinity of 440 nm to 470 nm that is a blue wavelength band, and emits blue light LB having a center wavelength of 455 ± 10 nm. As shown in FIG. 7, the red LED 45 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 center wavelength of 620 ± 10 nm. Further, as shown in FIG. 8, the purple LED 46 has, for example, a wavelength component in the vicinity of 395 nm to 415 nm, which is a purple wavelength band, and emits purple light LV having a center wavelength of 405 ± 10 nm.

  In FIG. 9, the green semiconductor light source 36 emits mixed light (LBe + LGf) of the blue excitation light LBe emitted from the excitation light LED 44 and the green fluorescence LGf emitted from the green phosphor 47 when excited by the blue excitation light LBe. The blue excitation light LBe has a wavelength component in the vicinity of 420 nm to 440 nm, which is a wavelength band from purple to blue, for example, and has a center wavelength of 430 ± 10 nm. The green fluorescence LGf is, for example, light having a wavelength component in the vicinity of 500 nm to 600 nm, which is a green wavelength band, and having a center wavelength of 520 ± 10 nm. The wavelength band of the blue excitation light LBe partially overlaps the wavelength band of the blue light LB emitted from the blue semiconductor light source 35 and the wavelength band of the violet light LV emitted from the violet semiconductor light source 38 (see also FIG. 19 and the like).

  The green phosphor 47 absorbs most of the blue excitation light LBe and emits green fluorescence LGf, but part of the blue excitation light LBe is not absorbed by the green phosphor 47 and passes through the green phosphor 47. For this reason, the light emission spectrum of the light emitted from the green semiconductor light source 36 includes two color components, that is, a part of blue excitation light LBe transmitted through the green phosphor 47 and the green fluorescence LGf, as shown.

  The purple semiconductor light source 38 is a light source for blood vessel enhancement observation (semiconductor light source for acquiring blood vessel information). In FIG. 10 showing the absorption spectrum of blood hemoglobin, the absorption coefficient μa of blood hemoglobin has a wavelength dependency, rapidly increases in a wavelength band of 450 nm or less, and has a peak in the vicinity of 405 nm. . Moreover, although it is a low value compared with the wavelength band of 450 nm or less, it also has a peak in the wavelength band of 530 nm to 560 nm. When the observation region is irradiated with light having a wavelength band having a large extinction coefficient μa, the blood vessel absorbs a large amount, and an image having a difference in contrast between the blood vessel and the other portion is obtained.

  Further, as shown in FIG. 11, the light scattering characteristic of the living tissue also has wavelength dependence, and the scattering coefficient μS increases as the wavelength becomes shorter. Scattering affects the depth of light penetration into living tissue. That is, the greater the scattering, the more light that is reflected near the mucosal surface layer of the biological tissue and the less light that reaches the mid-depth layer. Therefore, the shorter the wavelength, the lower the depth of penetration, and the longer the wavelength, the higher the depth of penetration. In view of such light absorption characteristics of hemoglobin and light scattering characteristics of living tissue, the wavelength of light for blood vessel enhancement is selected.

  The violet light LV having a central wavelength of 405 ± 10 nm emitted from the violet LED 46 has a relatively short wavelength and a low depth of penetration, so that the absorption by the surface blood vessels is large. For this reason, the purple light LV is used as light for emphasizing the surface blood vessels. By using the purple light LV, it is possible to obtain a blood vessel emphasized observation image in which surface blood vessels are depicted with high contrast. Further, as the light for emphasizing the middle-layer blood vessel, light in the green wavelength band of white light LW (see FIG. 12) is used. In the absorption spectrum shown in FIG. 10, the absorption coefficient gradually changes in the green wavelength band of 530 nm to 560 nm as compared to the blue wavelength band of 450 nm or less. The narrow bandwidth is not required. Therefore, as will be described later, a green image signal that is color-separated from white light by a G-color microcolor filter of the image sensor 56 is used for medium-depth blood vessel enhancement.

  In FIG. 3, drivers 50, 51, 52, and 53 are connected to the LEDs 43 to 46, respectively. The light source control unit 42 controls the lighting and extinguishing of the LEDs 43 to 46 and the amount of light through the drivers 50 to 53. The amount of light is controlled by changing the power supplied to each of the LEDs 43 to 46 based on an exposure control signal received from the processor device 12.

  Each driver 50-53 lights each LED43-46 by giving a drive current to each LED43-46 continuously under control of the light source control part 42. As shown in FIG. Then, according to the exposure control signal received from the processor unit 12, the power supplied to the LEDs 43 to 46 is changed by changing the drive current value to be applied, and the blue light LB, the green fluorescence LGf, the red light LR, and the purple light are changed. The amount of LV light is controlled. The light amount control of the green fluorescence LGf is performed by controlling the light amount of the blue excitation light LBe of the excitation light LED 44. For this reason, when increasing the light quantity of the green fluorescence LGf, the drive current value given from the driver 51 to the excitation light LED 44 is increased in order to increase the light quantity of the blue excitation light LBe. PAM (Pulse Amplitude Modulation) control that changes the amplitude of the drive current pulse, and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse. May be performed.

  The optical path integration unit 41 integrates the optical paths of the respective color lights emitted from the semiconductor light sources 35 to 38 into one optical path. The light emitting part of the optical path integrating part 41 is disposed in the vicinity of the receptacle connector 54 to which the light source connector 29b is connected. The optical path integrating unit 41 emits the light incident from each of the semiconductor light sources 35 to 38 to the incident end 55 a of the light guide 55 of the endoscope 11. Although not shown, each of the light source connector 29b and the receptacle connector 54 is provided with protective glass.

  FIG. 12 shows emission spectra of the mixed light of the blue light LB, the green fluorescence LGf, and the red light LR from the blue, green, and red semiconductor light sources 35 to 37 integrated by the optical path integration unit 41. This mixed light is used as white light LW. Since the blue excitation light LBe is cut by the third dichroic mirror 81 (see FIG. 18) as will be described later, the emission spectrum of the blue excitation light LBe is not superimposed on the emission spectrum of the white light LW. Note that the emission spectrum of the white light LW illustrated in FIG. 12 is an example, and the emission spectrum of the target white light LW may be variously changed according to the color of the desired display image. Specifically, the ratio of the amount of light of the blue light LB, the green fluorescence LGf, and the red light LR (the ratio of the drive current values of the LEDs 43 to 45) is changed to generate the white light LW of the target emission spectrum.

  The light source controller 42 controls the exposure of illumination light while maintaining the target emission spectrum. When the ratio of the amount of each color light constituting the illumination light changes, the emission spectrum of the illumination light changes and the color of the display image changes. For this reason, the light source control part 42 changes the drive current value given to each LED43-46 through each driver 50-53 independently so that the ratio of the light quantity of each color light may become constant, and increases / decreases the light quantity of each color light.

  Further, the light source control unit 42 changes the emission spectrum of the illumination light in the normal observation mode and the blood vessel enhancement observation mode. In the blood vessel emphasis observation mode, the purple light LV for emphasizing the surface blood vessels is emitted in addition to the white light LV, so that the emission spectrum of the illumination light is obtained by adding the violet light LV to the white light LW. The light source control unit 42 compares the blue light LB with respect to the normal observation mode so that the purple light LV is dominant over the blue light LB in the emission spectrum of the mixed light of the white light LW and the purple light LV. Reduce the proportion of light.

  In FIG. 3, the endoscope 11 includes a light guide 55, an imaging device 56, an analog processing circuit 57 (AFE: Analog Front End), and an imaging control unit 58. The light guide 55 is a fiber bundle obtained by bundling a plurality of optical fibers. When the light source connector 29 b is connected to the light source device 13, the incident end 55 a of the light guide 55 disposed on the light source connector 29 b faces the emission end of the optical path integrating portion 41. The emission end of the light guide 55 located at the distal end portion 19 branches into two at the front stage of the illumination window 22 so that light is guided to the two illumination windows 22.

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

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

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

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

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

  The image pickup device 56 is a color image pickup device, and B, G, and R three-color micro color filters having spectral characteristics as shown in FIG. 13 are assigned to each pixel on the image pickup surface 56a. The arrangement of the micro color filter is, for example, a Bayer arrangement.

  The B pixel to which the B filter is assigned is sensitive to light in the wavelength band of about 380 nm to 560 nm, and the G pixel to which the G filter is assigned is sensitive to light in the wavelength band of about 450 nm to 630 nm. The R pixel to which the R filter is assigned is sensitive to light in the wavelength band of about 580 nm to 800 nm. The blue light LB, the green fluorescence LGf, and the red light LR that constitute the white light LW are mainly reflected by the B pixel for reflected light corresponding to the blue light LB, and mainly reflected by the G pixel and red light LR for the green fluorescence LGf. The reflected light is received mainly by the R pixel. The reflected light corresponding to the purple light LV for blood vessel enhancement observation is received by the B pixel. The blue excitation light LBe is cut by the third dichroic mirror 81 and is not irradiated to the observation site. However, if the blue excitation light LBe is irradiated, the B pixel is sensitive to the reflected light corresponding to the blue excitation light LBe. To do.

  As shown in FIGS. 14 and 15, the imaging device 56 performs an accumulation operation for accumulating signal charges in the pixels and a read operation for reading out the accumulated signal charges within an acquisition period of one frame. In FIG. 14, in the normal observation mode, the semiconductor light sources 35 to 37 except the purple semiconductor light source 38 are turned on in accordance with the accumulation operation timing of the image sensor 56, and blue light LB, green fluorescence LGf, and red light are used as illumination light. White light LW (LB + LGf + LR) composed of mixed light of LR is irradiated onto the observation site, and the reflected light enters the image sensor 56. The image sensor 56 separates the reflected light of the white light LW with a micro color filter. The B pixel receives reflected light corresponding to the blue light LB, the G pixel receives reflected light corresponding to the green fluorescence LGf, and the R pixel receives reflected light corresponding to the red light LR. The image sensor 56 sequentially outputs the image signals B, G, and R for one frame in which the pixel values of each of the B, G, and R pixels are mixed according to the frame rate in accordance with the readout timing. Such an imaging operation is repeated while the normal observation mode is set.

  In FIG. 15, in the blood vessel enhancement observation mode, the purple semiconductor light source 38 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 each of the semiconductor light sources 35 to 38 is turned on, purple light LV is added together with white light LW that is the same as in the normal observation mode, and the mixed light (LW + LV) is irradiated onto the observation site as illumination light.

  As in the normal observation mode, the illumination light in which the purple light LV is added to the white light LW is split by the micro color filter of the image sensor 56. The B pixel receives reflected light corresponding to the purple light LV in addition to the reflected light corresponding to the blue light LB. Similar to the normal observation mode, the G pixel and the R pixel receive reflected light corresponding to the green fluorescence LGf and reflected light corresponding to the red light LR, respectively. Even in the blood vessel enhancement observation mode, the image sensor 56 sequentially outputs the image signals B, G, and R according to the frame rate in accordance with the readout timing. Such an imaging operation is repeated while the blood vessel enhancement observation mode is set.

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

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

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

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

  As shown in FIG. 16, in the normal observation mode, the image processing unit 67 generates a normal observation image based on the image signals B, G, and R color-separated into B, G, and R colors by the DSP 66. . This normal observation image is output to the monitor 14. The image processing unit 67 updates the normal observation image every time the image signals B, G, and R in the frame memory 68 are updated.

  As shown in FIG. 17, in the blood vessel enhancement observation mode, the image processing unit 67 generates a blood vessel enhancement observation image based on the image signals B, G, and R. Since the image signal B in the blood vessel enhancement observation mode includes a reflected light component corresponding to the purple light LV in addition to the reflected light component corresponding to the blue light LB constituting the white light LW, the surface layer blood vessel is included. Is drawn with high contrast. In lesions such as cancer, there is a tendency for the density of superficial blood vessels to be higher compared to normal tissues, so there is a characteristic in blood vessel patterns, so in blood vessel enhancement observation for the purpose of tumor quality discrimination, It is preferable that the superficial blood vessel is clearly depicted.

  In order to emphasize the surface blood vessels more, for example, a region of the surface blood vessels in the image may be extracted based on the image signal B, and contour enhancement processing or the like may be performed on the extracted surface blood vessel regions. Then, the image signal B that has been subjected to the contour enhancement process is combined with a full-color image generated based on the image signals B, G, and R. The same processing may be performed on the middle- and deep-layer blood vessels in addition to the surface blood vessels. In the case of emphasizing the middle-and-deep blood vessel, the region of the middle-and-deep blood vessel is extracted from the image signal G including a lot of information of the middle-and-deep blood vessel, and the contour enhancement process is performed on the extracted middle-and-deep blood vessel region Thus, the enhanced image signal G is combined with a full-color image generated from the image signals B, G, and R.

  Since the blood vessel emphasized observation image is generated based on the image signals B, G, and R in the same manner as the normal observation image, the observation site can be displayed in full color. However, the image signal B in the blood vessel enhancement observation mode has a higher blue density than the image signal B in the normal observation mode. Therefore, when generating a blood vessel-enhanced observation image, color correction such as suppression of blue density may be performed so that the same color as that of the normal observation image is obtained. The image processing unit 67 generates a blood vessel enhancement observation image every time the image signals B, G, and R in the frame memory 68 are updated.

  As a method for generating a blood vessel enhancement observation image, without using the image signal R, a blood vessel enhancement observation image is generated using only the two colors of the image signals B and G, and the image signal B is converted into the B channel of the monitor 14 and the image signal B. A method of displaying the observation region in pseudo color, such as a method of assigning the image signal G to the R channel of the monitor 14 for the G channel, may be employed.

  In FIG. 18, the optical path integrating unit 41 includes collimator lenses 75, 76, 77, and 78 that collimate each color light emitted from each semiconductor light source 35 to 38, a first dichroic mirror 79, a second dichroic mirror 80, and a third dichroic mirror. 81 (corresponding to the “optical path integrating optical member” of the present invention) and a condensing lens 82 that condenses the light emitted from the optical path integrating portion 41 on the incident end 55a of the light guide 55. Each of the dichroic mirrors 79 to 81 is an optical member in which a dichroic filter having predetermined transmission characteristics 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 first dichroic mirror 79 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 and the purple semiconductor light source 38 are also arranged so that their optical axes are orthogonal to each other, and a second dichroic mirror 80 is provided at a position where these optical axes are orthogonal. In addition, by the action of the first and second dichroic mirrors 79 and 80, all the optical paths of the blue light LB, the mixed light of the blue excitation light LBe and the green fluorescence LGf, the red light LR, and the purple light LV finally cross each other. A third dichroic mirror 81 is provided. The first dichroic mirror 79 is the optical axis of the green semiconductor light source 36 and the red semiconductor light source 37, the second dichroic mirror 80 is the optical axis of the blue semiconductor light source 35 and the purple semiconductor light source 38, and the third dichroic mirror 81 is the blue semiconductor light source 35 and green. The semiconductor light sources 36 are arranged at an angle of 45 ° with respect to the optical axis of the semiconductor light source 36.

  As shown in FIG. 19, the dichroic filter of the first dichroic mirror 79 has a characteristic of reflecting light in a wavelength band of about 610 nm or more and transmitting light in a wavelength band of less than that. The first dichroic mirror 79 transmits the mixed light of the blue excitation light LBe and the green fluorescence LGf incident from the green semiconductor light source 36 via the collimator lens 76 to the downstream side, and enters from the red semiconductor light source 37 via the collimator lens 77. The reflected red light LR is reflected. Thereby, the mixed light of the blue excitation light LBe and the green fluorescence LGf and the optical path of the red light LR are integrated.

  As shown in FIG. 20, the dichroic filter of the second dichroic mirror 80 has a characteristic of reflecting light in a wavelength band of less than about 430 nm and transmitting light in a wavelength band of more than that. The second dichroic mirror 80 transmits the blue light LB incident from the blue semiconductor light source 35 via the collimator lens 75 to the downstream side, and reflects the purple light LV incident from the purple semiconductor light source 38 via the collimator lens 78. Thereby, the optical paths of the blue light LB and the purple light LV are integrated.

  The dichroic filter of the third dichroic mirror 81 has transmission characteristics excluding at least the blue excitation light LBe from the emission spectrum of the mixed light of the blue excitation light LBe and the green fluorescence LGf shown in FIG. That is, the dichroic filter of the third dichroic mirror 81 functions as an excitation light cut filter that cuts the blue excitation light LBe.

  Specifically, as shown in FIG. 21, the dichroic filter of the third dichroic mirror 81 has a characteristic of reflecting light in a wavelength band less than about 490 nm and transmitting light in a wavelength band higher than that. . Therefore, the third dichroic mirror 81 reflects the blue excitation light LBe out of the mixed light of the blue excitation light LBe and the green fluorescence LGf transmitted through the first dichroic mirror 79, and transmits the green fluorescence LGf. The third dichroic mirror 81 transmits the red light LR reflected by the first dichroic mirror 79. Further, the third dichroic mirror 81 reflects the blue light LB transmitted through the second dichroic mirror 80 and the purple light LV reflected by the second dichroic mirror 80. By the third dichroic mirror 81, all the optical paths of the blue light LB, the green fluorescence LGf, the red light LR, and the violet light LV are integrated. Further, the blue excitation light LBe does not enter the incident end 55a of the light guide 55, and irradiation of the observation site of the blue excitation light LBe is prevented.

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

  The insertion part 16 of the endoscope 11 is inserted into the subject's digestive tract, and observation in the digestive tract is started. In the normal observation mode, the semiconductor light sources 35 to 37 except for the purple semiconductor light source 38 are lit. The light source control unit 42 sets the drive current value to be applied to the LEDs 43 to 45 to a value for the normal observation mode, and starts lighting the semiconductor light sources 35 to 37. Then, the light amount control is performed while maintaining the target emission spectrum.

  The blue and red semiconductor light sources 35 and 37 emit blue light LB and red light LR by the blue and red LEDs 43 and 45, respectively. The green semiconductor light source 36 emits mixed light of blue excitation light LBe by the excitation light LED 44 and green fluorescence LGf by the green phosphor 47 excited by the blue excitation light LBe. Each color light enters the collimator lenses 75 to 77 of the optical path integration unit 41.

  The red light LR is reflected by the first dichroic mirror 79 and passes through the third dichroic mirror 81. The mixed light of the blue excitation light LBe and the green fluorescence LGf passes through the first dichroic mirror 79. Of the mixed light, the blue excitation light LBe is reflected by the third dichroic mirror 81, and the green fluorescence LGf is transmitted through the third dichroic mirror 81. The first dichroic mirror 79 integrates the optical path of the mixed light of the red light LR, the blue excitation light LBe, and the green fluorescence LGf. Further, the blue excitation light LBe is cut by the third dichroic mirror 81. Since the dichroic filter of the third dichroic mirror 81 functions as an excitation light cut filter, the configuration of the optical system of the optical path integrating unit 41 can be simplified.

  The blue light LB passes through the second dichroic mirror 80 and is reflected by the third dichroic mirror 81. The second and third dichroic mirrors 80 and 81 integrate the optical paths of the blue light LB, the green fluorescence LGf, and the red light LR. These blue light LB, green fluorescence LGf, and red light LR are incident on the condenser lens 82. Thereby, white light LW composed of blue light LB, green fluorescence LGf, and red light LR is generated. The condensing lens 82 condenses the white light LW on the incident end 55 a of the light guide 55 of the endoscope 11 and supplies the white light LW to the endoscope 11.

  In the endoscope 11, the white light LW is guided to the illumination window 22 through the light guide 55 and irradiated from the illumination window 22 to the observation site. The reflected light of the white light LW reflected at the observation site enters the image sensor 56 from the observation window 23. The image sensor 56 outputs the image signals B, G, and R to the DSP 66 of the processor device 12. The DSP 66 separates the image signals B, G, and R and inputs them to the image processing unit 67. The imaging operation by the imaging device 56 is repeated at a predetermined frame rate. The image processing unit 67 generates a normal observation image based on the input image signals B, G, and R. The normal observation image is output to the monitor 14 through the display control circuit 69. The normal observation image is updated according to the frame rate of the image sensor 56.

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

  When changing the light quantity of the green fluorescence LGf in the exposure control, the light quantity of the blue excitation light LBe of the excitation light LED 44 is changed. As shown in FIG. 19 and the like, the wavelength band of the blue excitation light LBe partially overlaps with the wavelength band of the blue light LB. For this reason, if the blue excitation light LBe is emitted as illumination light, the light quantity of the blue light LB also changes with the change in the light quantity of the blue excitation light LBe, and the emission spectrum of the illumination light changes. However, since the blue excitation light LBe is cut by the third dichroic mirror 81, the blue excitation light LBe does not affect the light amount of the blue light LB, and the light amount of the blue light LB is independent of the green fluorescence LGf. Can be controlled. Therefore, even if exposure control is performed, illumination light having an emission spectrum suitable for the normal observation mode can always be supplied to the endoscope 11, and the color of the normal observation image does not change.

  When a suspicious part and a suspicious observation site are found in the normal observation mode, the normal observation mode is switched to the blood vessel enhancement observation mode. In the blood vessel enhancement observation mode, the purple semiconductor light source 38 is turned on in addition to the semiconductor light sources 35 to 37. Each color light from each of the semiconductor light sources 35 to 37 becomes white light LW by the action of the optical path integration unit 41 described above, and is supplied to the endoscope 11.

  The purple semiconductor light source 38 emits purple light LV from the purple LED 46. The purple light LV is incident on the collimator lens 78. The purple light LV is reflected by the second and third dichroic mirrors 80 and 81. By the second and third dichroic mirrors 80 and 81, the purple light LV is integrated into the same optical path as the white light LW. These purple light LV and white light LW are incident on the condenser lens 82. The condensing lens 82 condenses the purple light LV and the white light LW on the incident end 55 a of the light guide 55 of the endoscope 11 and supplies the purple light LV and the white light LW to the endoscope 11. In this way, the purple light LV and the white light LW are simultaneously irradiated to the observation site. Also in this case, since the blue excitation light LBe is cut by the third dichroic mirror 81 as in the normal observation mode, illumination light having an emission spectrum suitable for the blood vessel enhancement observation mode is always supplied to the endoscope 11. it can.

  The image sensor 56 receives the reflected light at the observation site of the white light LW and the purple light LV, and outputs B, G, and R image signals to the DSP 66. The DSP 66 separates the image signals B, G, and R and inputs them to the image processing unit 67. The image processing unit 67 generates a blood vessel enhancement observation image based on the B, G, and R image signals. The blood vessel enhancement observation image is output to the monitor 14. The blood vessel enhancement observation image is updated according to the frame rate of the image sensor 56.

  Since illumination light having an emission spectrum suitable for the blood vessel enhancement observation mode is always irradiated, the reliability of the blood vessel enhancement observation image is increased. Since the blood vessel emphasized observation image is used for the discrimination of tumor quality, if the reliability of the blood vessel emphasized observation image increases, the result of the tumor quality discrimination becomes reliable.

Since the blue excitation light LBe that affects the light amounts of the blue light LB and the purple light LV is cut by the third dichroic mirror 81, the amount of change in the blue excitation light LBe that accompanies the change in the light amount of the green fluorescence LGf is taken into account. Illumination light having a target emission spectrum can be stably obtained without complicated control such as increasing or decreasing the amount of light of LB or purple light LV.
[Second Embodiment]
In the first embodiment, the dichroic filter of the third dichroic mirror 81 that integrates the mixed light of the blue excitation light LBe and the green fluorescence LGf emitted from the green semiconductor light source 36 and the blue light LB emitted from the blue semiconductor light source 35 is excited. Although the function of the light cut filter is achieved, a function of the excitation light cut filter may be assigned to a dichroic filter of a dichroic mirror different from the third dichroic mirror 81.

  For example, as in the optical path integrating unit 90 shown in FIG. 22, the function of the excitation light cut filter is the same as that of the mixed light of the blue excitation light LBe and the green fluorescence LGf emitted from the green semiconductor light source 36 and the red light LR emitted from the red semiconductor light source 37. You may make it bear on the dichroic filter of the 1st dichroic mirror 91 (equivalent to the 1st dichroic mirror 79 of the said 1st Embodiment. It respond | corresponds to the "optical member for optical path integration" of this invention) which integrates an optical path. The optical path integration unit 91 in FIG. 22 is the same as the optical path integration unit 41 in the first embodiment except that the first dichroic mirror 79 in the first embodiment is replaced with the first dichroic mirror 91.

In this case, as shown in FIG. 23, the dichroic filter of the first dichroic mirror 91 reflects light in a wavelength band of about 610 nm or more and light in a wavelength band of less than about 490 nm, and light in other wavelength bands. It has the property of transmitting light. That is, the band pass characteristic is obtained by combining the transmission characteristics of the first dichroic mirror 79 and the third dichroic mirror 81 of the first embodiment. However, when such a bandpass characteristic is provided, the manufacturing cost is higher than that of a short path that reflects light on the long wavelength side and transmits light on the short wavelength side, or vice versa, so that the manufacturing cost increases. As in the first embodiment, it is advantageous in terms of cost that the function of the excitation light cut filter is assigned to the dichroic filter of the third dichroic mirror 81 having a long pass characteristic.
[Third Embodiment]
In each of the above embodiments, the example in which the dichroic mirror also serves as the excitation light cut filter has been described. However, the excitation light cut filter is provided separately from the dichroic mirror as in the optical path integration unit 95 of the third embodiment shown in FIG. Also good. In the optical path integration unit 95, an excitation light cut filter 96 is disposed between the green semiconductor light source 36 and the first dichroic mirror 79. For example, as shown in FIG. 25, the excitation light cut filter 96 has a characteristic of reflecting light in the violet and blue wavelength bands of less than about 450 nm and transmitting light in the other green and red wavelength bands. Although not shown, an excitation light cut filter 96 may be provided between the first dichroic mirror 79 and the third dichroic mirror 81. In short, it is only necessary to prevent the blue excitation light LBe from entering the incident end 55a of the light guide 55, and the excitation light cut filter is more specifically green on the optical path between the excitation light LED 44 and the light guide 55. It is only necessary to be provided on a position where the mixed light of the blue excitation light LBe and green fluorescence LGf emitted by the semiconductor light source 36 and the optical path of the blue light LB emitted by the blue semiconductor light source 35 are integrated, or on the upstream optical path of the position. .
[Fourth Embodiment]
In the first embodiment, the light amount control of each color light is performed by changing the drive current value given to each LED 43 to 46 based on the exposure control signal from the processor device 12, but the heat generation of the LED and the phosphor. In some cases, the output light quantity of the semiconductor light source varies with respect to the driving current value due to the influence of the above and the deterioration with time. Therefore, a light quantity measurement sensor for measuring the light quantity of each color light may be provided to monitor whether or not the light quantity of each color light has reached the target value based on the light quantity measurement signal output from the light quantity measurement sensor.

  In FIG. 26, in addition to the configuration of the optical path integration unit 41 shown in FIG. 18 of the first embodiment, the optical path integration unit 100 measures blue, green, and red for measuring the amount of each color light emitted from each semiconductor light source 35-38. Each light quantity measurement sensor 101 is provided in front of each of the purple light quantity measurement sensors 101, 102, 103, 104 and the respective semiconductor light sources 35 to 38, and reflects a part of each color light emitted from each of the semiconductor light sources 35 to 38. Glass plates 105, 106, 107, and 108 for guiding light to .about.104.

  Each glass plate 105-108 is arrange | positioned with the attitude | position inclined, for example by 35 degrees with respect to the optical axis of each semiconductor light source 35-38. Each glass plate 105-108 transmits each color light which each semiconductor light source 35-38 emits. When each color light enters each of the glass plates 105 to 108, Fresnel reflection occurs. Each of the glass plates 105 to 108 uses this Fresnel reflection to guide a part of light (about 4% to 8%) of each color light emitted from each of the semiconductor light sources 35 to 38 to each of the light quantity measuring sensors 101 to 104. The light guide member. In addition, it may replace with a glass plate and may use other light guide members, such as an optical fiber.

  Filters 109 and 110 are provided in front of the green light quantity measurement sensor 102 and the red light quantity measurement sensor 103, respectively. The filter 109 is for limiting the light incident on the green light quantity measurement sensor 102 to only light in the wavelength band of the green fluorescence LGf that constitutes part of the white light LW that is finally supplied to the endoscope 11. As shown in FIG. 27, it reflects light in the red wavelength band of about 610 nm or more and light in the purple and blue wavelength bands of less than about 490 nm and transmits light in the other green wavelength band. Have. That is, the filter 109 has a bandpass characteristic that combines the transmission characteristics of the first dichroic mirror 79 and the third dichroic mirror 81 of the first embodiment, as with the first dichroic mirror 91 of the second embodiment. Only the green fluorescence LGf, which is finally emitted as part of the white light LW, from which the blue excitation light LBe is cut, enters the green light quantity measurement sensor 102 by the filter 109. The pure light quantity of the green fluorescence LGf can be measured.

  Further, the filter 110 limits the light incident on the red light quantity measurement sensor 103 to only light in the wavelength band of the red light LR that forms part of the white light LW that is finally supplied to the endoscope 11. As shown in FIG. 28, it has characteristics of reflecting light in the green and blue wavelength bands of less than about 610 nm and transmitting light in the red wavelength band of more than that. That is, the filter 110 has a transmission characteristic obtained by inverting the transmission characteristic shown in FIG. 19 of the first dichroic mirror 79 of the first embodiment. Only the red light LR finally emitted as part of the white light LW is incident on the red light quantity measurement sensor 103 by the filter 110. The pure light quantity of the red light LR can be measured.

  In FIG. 29, each light quantity measurement sensor 101-104 receives each color light guided by Fresnel reflection of the glass plates 105-108, and outputs a light quantity measurement signal corresponding to the light quantity of each received color light. Is output to the light source controller 42. The light source control unit 42 compares the light quantity measurement signal with the target light quantity, and based on the comparison result, the drive current applied to each of the semiconductor light sources 35 to 38 set in the exposure control so that the light quantity becomes the target value. Fine tune the value. As described above, the light amount of each color light is constantly monitored by the light amount measurement sensors 101 to 104, and the light amount can be controlled to always follow the target value by finely adjusting the drive current value given based on the measurement result of the light amount. . For this reason, the illumination light of the target emission spectrum can be obtained more stably.

  Note that, as in the optical path integration unit 115 shown in FIG. 30, a filter is provided at a position between the green semiconductor light source 36 and the first dichroic mirror 79 (the same position as the excitation light cut filter 96 shown in FIG. 24 of the third embodiment). An excitation light cut filter 116 having the same transmission characteristics as 109 may be provided. In this way, the filter 109 becomes unnecessary. However, since the excitation light cut filter 116 is larger than the filter 109, it is more preferable to provide the filter 109 than the excitation light cut filter 116 from the viewpoint of cost and space saving.

  In the fourth embodiment, the light quantity measurement sensors are arranged for all the semiconductor light sources to monitor the light quantity, but at least the blue, green and red semiconductor light sources that emit light constituting the white light LW, and the fluorescent type The light quantity of the semiconductor light source is monitored, and the light quantity measurement sensor need not be arranged for the other semiconductor light sources. In addition, among the blue, green, and red semiconductor light sources, only the light amount of the semiconductor light source (fluorescence type semiconductor light source) in which the fluctuation of the output light amount with respect to the drive current value is particularly large may be selectively monitored.

  The fluorescent semiconductor light source is not limited to the green semiconductor light source 36 of each of the above embodiments. Instead of or in addition to the green semiconductor light source, a red semiconductor light source is used to emit blue excitation light emitting elements that emit blue excitation light in the purple to blue wavelength band, and red fluorescence in the red wavelength band that is excited by blue excitation light. You may comprise with the emitted red fluorescent substance. Also in this case, as in each of the above embodiments, the excitation light cut filter is a position where the mixed light of the blue excitation light and the red fluorescence emitted from the red semiconductor light source and the optical path of the blue light emitted from the blue semiconductor light source are integrated, or the position thereof. As long as it is provided on the upstream optical path. For example, as in the first embodiment, the dichroic filter of the third dichroic mirror 81 may have the function of the excitation light cut filter, or the excitation light cut between the first dichroic mirror 79 and the third dichroic mirror 81. A filter may be provided, or an excitation light cut filter may be provided between the red semiconductor light source and the first dichroic mirror 79.

When the red semiconductor light source is composed of a fluorescent semiconductor light source, the excitation light emitting element is not limited to the blue excitation light emitting element emitting blue excitation light in the purple to blue wavelength band, and emits green excitation light in the green wavelength band. It may be a green excitation light emitting element. In this case, an excitation light cut filter having a transmission characteristic that cuts green excitation light and transmits red fluorescence is disposed between the red semiconductor light source and the first dichroic mirror 79 in, for example, the optical path integration unit 41 of FIG.
[Fifth Embodiment]
Further, a white semiconductor light source 121 may be used as a fluorescent semiconductor light source as in the light source unit 120 shown in FIG. The light source unit 120 is obtained by removing the green semiconductor light source 36 and the red semiconductor light source 37 from the light source unit 40 of the first embodiment and providing a white semiconductor light source 121 instead. Further, the optical path integrating unit 122 is obtained by removing the collimator lens 77 and the first dichroic mirror 79 related to the green semiconductor light source 36 and the red semiconductor light source 37 from the optical path integrating unit 41 of the first embodiment.

  The white semiconductor light source 121 includes a blue excitation light emitting element that emits blue excitation light LBe in the blue wavelength band, and green that emits green fluorescence LGf and red fluorescence LRf in the green and red wavelength bands when excited by the blue excitation light LBe. It is composed of a red phosphor. In this case, the white light LW is composed of mixed light of the blue light LB emitted from the blue semiconductor light source 35 and the green fluorescence LGf and red fluorescence LRf emitted from the white semiconductor light source 121. Also in this embodiment, the wavelength band of the blue excitation light LBe emitted from the white semiconductor light source 121 overlaps the wavelength band of the blue light LB emitted from the blue semiconductor light source 35. For this reason, the aspect which has the blue semiconductor light source 35 of this embodiment and the white semiconductor light source 121 is excited by the excitation light which a fluorescence type semiconductor light source emits similarly to the aspect which has the three color semiconductor light sources 35-37 of each said embodiment. There arises a problem that the light amount of the light overlapping with the wavelength band is affected, and the emission spectrum of the illumination light is changed.

  A dichroic mirror 123 is disposed at a position where the light emitted from each of the semiconductor light sources 35, 38, and 121 finally intersects. The dichroic mirror 123 corresponds to the third dichroic mirror 81 of the first embodiment. The dichroic filter of the dichroic mirror 123 has a characteristic of reflecting the purple light LV, the blue excitation light LBe, and the blue light LB, and transmitting the green fluorescence LGf and the red fluorescence LRf, and cutting the blue excitation light LBe. Functions as a filter. By this dichroic mirror 123, all optical paths of the respective color lights are integrated, and transmission of the blue excitation light LBe is blocked.

  In the present embodiment as well, the excitation light cut filter may be provided separately from the dichroic mirror 123 as in the third embodiment. Further, as in the fourth embodiment, for example, a light quantity measurement sensor may be provided in the white semiconductor light source 121 to monitor the light quantity.

Further, the LED mounting form of the first embodiment is merely an example, and other forms may be adopted. For example, a microlens that adjusts the divergence angle may be provided on the light emitting surface of the sealing resin 35c or the green phosphor 47 in FIGS. 4 and 5, or a bullet having a microlens formed instead of the surface mount type. The form which accommodated LED in the case of the type | mold may be sufficient. In addition, as an example of the green semiconductor light source 36, the green phosphor 47 is provided integrally with the substrate 36a in addition to the excitation light LED 44, but the green phosphor 47 and the substrate 36a may be provided separately. In this case, a light guide member such as a lens or an optical fiber is added between the excitation light LED 44 and the green phosphor 47, and the excitation light of the excitation light LED 44 is guided to the green phosphor 47 through the light guide member. To do.
[Sixth Embodiment]
Furthermore, although the example using the LED as the light emitting element has been described, a laser diode (LD) may be used instead of the LED. For example, as shown in FIG. 32, a green semiconductor light source 130 composed of an excitation light LD 131 that emits blue excitation light and a green phosphor 132 disposed in front of the excitation light LD 131 is used as the excitation light emitting element. -You may use instead of the green semiconductor light source 36 of 4th Embodiment.

  In this case, the green phosphor 132 is formed on the surface of the disk-shaped transparent rotating plate 133 by a method such as coating. Then, the rotating plate 133 is rotated by a rotating mechanism 134 such as a motor, and the blue excitation light from the excitation light LD 131 is irradiated to the eccentric position of the rotating plate 133. By rotating the rotating plate 133, the irradiation position of the excitation light does not concentrate on one place of the green phosphor 132. When the irradiation position of the excitation light is concentrated at one place, the place becomes a high temperature and the deterioration of the green phosphor 132 is accelerated, but this can be prevented. Reference numeral 135 denotes a condensing lens that condenses the blue excitation light emitted by the excitation light LD 131 on the rotating plate 133.

  An excitation light cut filter may be integrally formed on the surface on the emission side of the rotating plate 133. Moreover, as a light emitting element, you may use an organic EL (Electro-Luminescence) element other than LED and LD. An LD or an organic EL element may be used as a light emitting element of other semiconductor light sources (blue semiconductor light source 35, purple semiconductor light source 38, etc.) without being limited to the fluorescent semiconductor light source.

  A white semiconductor light source 140 shown in FIG. 33 is a white version of the green semiconductor light source 130 of FIG. Similar to the green semiconductor light source 130, the white semiconductor light source 140 includes an excitation light LD 141 that emits blue excitation light, and green and red phosphors 142 disposed in front of the excitation light LD 141. This white semiconductor light source 140 may be used as the white semiconductor light source 121 of the fifth embodiment. Since the other components such as the rotating plate are the same as those of the green semiconductor light source 130 in FIG. 32, the same reference numerals as those in FIG.

  In each said embodiment, although the excitation light cut filter which cuts excitation light 100% was illustrated, this invention is not limited to this. The excitation light cut filter may be any filter that can reduce the amount of the excitation light to some extent. For example, a filter having a transmission characteristic that cuts the excitation light by 50% is also included in the present invention. However, the closer the value is to 100%, the better the effect is obtained.

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

  In each of the above embodiments, the purple semiconductor light source 38 that emits the purple light LV is exemplified as the blood vessel information acquisition semiconductor light source for acquiring the blood vessel information of the living tissue, but in addition to or in addition to the purple semiconductor light source 38, Another semiconductor light source for acquiring blood vessel information may be provided. For example, in order to acquire oxygen saturation of blood hemoglobin as blood vessel information, a semiconductor light source that emits blue light in a narrow band having a center wavelength of 473 ± 10 nm may be provided. Of course, when blood vessel information observation is not performed, only the blue, green, and red semiconductor light sources may be provided without providing the blood vessel information acquisition semiconductor light source.

  Further, in the first embodiment, only the white light is irradiated in the normal observation mode, and the white light LW and the purple light LV are simultaneously irradiated on the observation site in the blood vessel enhancement observation mode, and the white light is used in both modes. A mode that does not use white light may be provided. For example, the green semiconductor light source 36 and the purple semiconductor light source 38, or the green semiconductor light source 36 and the blue semiconductor light source 35 may be turned on, and a blood vessel enhancement observation image may be acquired based on the green fluorescence LGf.

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

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

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

DESCRIPTION OF SYMBOLS 10 Endoscope system 11 Endoscope 13 Light source device 35 Blue semiconductor light source 36, 130 Green semiconductor light source 37 Red semiconductor light source 38 Purple semiconductor light source 40, 120 Light source part 41, 90, 95, 100, 115, 122 Optical path integration part 42 Light source controller 43 Blue LED
44 Excitation light LED
45 Red LED
46 Purple LED
47, 132 Green phosphor 55 Light guide 56 Image sensor 79-81 First to third dichroic mirror 91 First dichroic mirror 96, 116 Excitation light cut filter 101-104 Light amount measurement sensor 105-108 Glass plate 109 Filter 121, 140 White semiconductor light source 123 Dichroic mirror 131, 141 Excitation light LD
133, 143 Rotating plate 142 Green and red phosphor

Claims (11)

In an endoscope light source device for supplying illumination light to a light guide of an endoscope,
An excitation light emitting element that emits excitation light in a wavelength band that at least partially overlaps the wavelength band of the illumination light, and at least one of the green or red wavelength bands that are excited by the excitation light and included in the illumination light A plurality of semiconductor light sources including a fluorescent semiconductor light source having a phosphor emitting fluorescence including one wavelength band;
An excitation light cut filter provided on an optical path between the excitation light emitting element and the light guide, for cutting the excitation light;
An optical path integrating optical member that integrates an optical path through which the fluorescence emitted from the fluorescent semiconductor light source passes and an optical path through which light emitted from a semiconductor light source other than the fluorescent semiconductor light source among the plurality of semiconductor light sources passes is provided. An endoscope light source device.   The endoscope light source device according to claim 1, wherein the excitation light cut filter is provided in the optical path integrating optical member.   The endoscope light source device according to claim 2, wherein a dichroic filter is formed on the optical path integrating optical member, and the dichroic filter also serves as the excitation light cut filter.   4. The endoscope light source device according to claim 1, wherein light emitted from a semiconductor light source other than the fluorescent semiconductor light source has a wavelength band overlapping with the excitation light. 5.   The endoscope light source device according to claim 1, wherein the excitation light cut filter is provided between the optical member for integrating an optical path and the fluorescent semiconductor light source. The plurality of semiconductor light sources are three semiconductor light sources that emit light in each wavelength band of blue, green, and red,
6. The fluorescent semiconductor light source is at least one of the three semiconductor light sources, and the phosphor emits either green or red fluorescence. The light source device for endoscopes according to any one of the above.   The fluorescent semiconductor light source includes a blue excitation light emitting element that emits blue excitation light in a purple to blue wavelength band, and a green phosphor that emits green fluorescence in a green wavelength band when excited by the blue excitation light. The endoscope light source device according to claim 6, wherein the endoscope light source device is a green semiconductor light source.   The fluorescent semiconductor light source includes a blue excitation light emitting element that emits blue excitation light in a purple to blue wavelength band or a green excitation light emitting element that emits green excitation light in a green wavelength band, and the blue excitation light or the green excitation. 7. The endoscope light source device according to claim 6, wherein the endoscope light source device is a red semiconductor light source composed of a red phosphor that is excited by light and emits red fluorescence in a red wavelength band.   9. The semiconductor light source according to claim 1, further comprising a purple semiconductor light source that emits light in a purple wavelength band for highlighting a blood vessel in a mucous membrane surface layer of a living tissue. The endoscope light source device described.   The endoscope light source device according to claim 1, wherein the excitation light emitting element is a light emitting diode. An endoscope having a light guide for guiding illumination light;
In an endoscope system comprising an endoscope light source device that supplies the illumination light to the light guide,
The endoscope light source device is:
An excitation light emitting element that emits excitation light in a wavelength band that at least partially overlaps the wavelength band of the illumination light, and at least one of the green or red wavelength bands that are excited by the excitation light and included in the illumination light A plurality of semiconductor light sources including a fluorescent semiconductor light source having a phosphor emitting fluorescence including one wavelength band;
An excitation light cut filter provided on an optical path between the excitation light emitting element and the light guide, for cutting the excitation light;
An optical path integrating optical member that integrates an optical path through which the fluorescence emitted from the fluorescent semiconductor light source passes and an optical path through which light emitted from a semiconductor light source other than the fluorescent semiconductor light source among the plurality of semiconductor light sources passes is provided. Endoscope system.

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