JP6533157B2 - LIGHT SOURCE DEVICE FOR ENDOSCOPE, OPERATION METHOD THEREOF, AND ENDOSCOPE SYSTEM - Google Patents

Description

  The present invention relates to an endoscope light source device capable of illuminating wide band light and narrow band light, an operation method thereof, and an endoscope system.

  In recent medical care, diagnosis and the like using an endoscope system including an endoscope light source device (hereinafter referred to as a light source device), an electronic endoscope (hereinafter referred to as an endoscope), and a processor device are widely used. It is Conventionally, lamp light sources such as xenon lamps and halogen lamps that emit white light as illumination light have been used as light source devices, but recently, laser diodes (LDs) that emit light of a specific color instead of lamp light sources Semiconductor light sources such as laser diodes and light emitting diodes (LEDs) are being used.

  Also, in recent years, a special light observation mode using wide band ordinary light to obtain a normal observation image with high color rendering and special light using special light such as narrow band light to obtain a special observation image with high blood vessel contrast 2. Description of the Related Art An endoscope system provided with an observation mode is in widespread use.

  For example, in the endoscope system of Patent Document 1, a normal light observation mode using white wide band light as normal light and a special light observation mode using narrow band light cut out from a wavelength band of wide band light as special light And have. Therefore, in Patent Document 1, a movable dichroic mirror that transmits only the wavelength band of a portion cut out from the wavelength band of the broadband light is used. The dichroic mirror is inserted into the light path of the light source in the special light observation mode, and is retracted from the light path of the light source in the normal light observation mode. The insertion and removal of the dichroic mirror is performed by the user operating the changeover switch or the like to select the observation mode. From the above configuration, in order to obtain a normal observation image and a special observation image, the user needs to switch the observation mode.

  On the other hand, as an endoscope system for observation using normal light and special light, there is known an endoscope system in which a user can obtain a normal observation image and a special observation image without switching the observation mode. For example, in the endoscope system of Patent Document 2, white light is used as normal light, and light obtained by adding light with a shorter wavelength than white light to white light is used as special light for blood vessel enhancement. Specifically, a first LD for exciting a phosphor to generate white light and a second LD for emitting light having a shorter wavelength than white light are provided, and only the first LD is turned on in the first frame period. In the second frame period, the first LD and the second LD are turned on.

International Publication No. 2012/101904 JP, 2013-188364, A

  Even in the endoscope system of Patent Document 1, there may be a demand for the user to acquire a normal observation image and a special observation image without switching the observation mode, but Patent Document 2 can not be applied to Patent Document 1. Specifically, in Patent Document 2, special light is generated by adding light having a shorter wavelength than white light to white light, so white light and blood vessel enhancement can be achieved by controlling the lighting of the LD as described above. Special light can be switched according to the frame period, but when using narrow band light partially cut out from the wavelength band of wide band light as special light as in Patent Document 1, the dichroic mirror is used. At present, it is necessary to insert and remove light, and it is difficult to switch between broadband light and narrow band light instantaneously in accordance with the frame period.

  An object of the present invention is to provide a light source device for an endoscope capable of generating wide band light and narrow band light without inserting and removing a dichroic mirror, an operation method thereof, and an endoscope system. Do.

The light source device for endoscopes of the present invention comprises a first light source having a first light emitting element for emitting first light, and a second light source having a second light emitting element for emitting second light having the same wavelength band as the first light. A third light source having a third light emitting element emitting a third light whose center wavelength is shorter than the wavelength bands of the first light and the second light, and a fourth light having the same wavelength band as the third light A fourth light source having a fourth light emitting element emitting light, and a first dichroic mirror having a first threshold and a second threshold in wavelength bands of the first light and the second light, the first dichroic mirror having the first threshold and the second threshold A first wavelength band of light having a first wavelength band between the first light and a second wavelength band of light having a second wavelength band outside the first wavelength band from the second light; a first dichroic mirror to integrate the optical path of the light path and the second wavelength band of light, the third light, and fourth light A third wavelength band light having a third threshold in a long band and having a third wavelength band equal to or less than the third threshold is generated from the third light, and a fourth wavelength band having a fourth wavelength band larger than the third threshold A second dichroic mirror that generates light from the fourth light and integrates the optical path of the third wavelength band light and the optical path of the fourth wavelength band light ; and driving the first light emitting element and the second light emitting element to generate the first light. Control to generate broadband light including wavelength band light and second wavelength band light, and driving the first light emitting element of the first light emitting element and the second light emitting element to generate narrow band light including the first wavelength band light There line and a control to generate a drive current applied to the first light emitting element, by controlling the drive current applied to the second light emitting element, the same light emission intensity of the first light and second light And a light source control unit configured to emit light.

The operating method of a light source device for an endoscope of the present invention comprises a first light source having a first light emitting element that emits a first light, and a second light emitting element that emits a second light having the same wavelength band as the first light. It has the same wavelength band as the third light source, and the third light source having the third light emitting element that emits the third light whose center wavelength is shorter than the wavelength bands of the first light and the second light. A fourth light source having a fourth light emitting element that emits a fourth light, and a first threshold and a second threshold within a wavelength band of the first light and the second light, and a second between the first threshold and the second threshold A first wavelength band light having one wavelength band is generated from the first light, a second wavelength band light having a second wavelength band outside the first wavelength band is generated from the second light, and an optical path of the first wavelength band light When a first dichroic mirror to integrate a second optical path of the wavelength band, the third threshold value to a third light, and fourth light within the wavelength band Yes A third wavelength band light having a third wavelength band equal to or less than a third threshold is generated from the third light, and a fourth wavelength band light having a fourth wavelength band larger than the third threshold is generated from the fourth light; In an operation method of a light source device for an endoscope , comprising: a second dichroic mirror integrating an optical path of three wavelength band light and an optical path of fourth wavelength band light, the light source control unit includes a first light emitting element and a second light emission. And driving the element to generate wide band light including the first wavelength band light and the second wavelength band light, and driving the first light emitting element of the first light emitting element and the second light emitting element to control the first wavelength There line and a control for generating a narrow-band light including band light, a drive current applied to the first light emitting element, by controlling the drive current applied to the second light emitting element, the first light And the second light are emitted with the same emission intensity .

  An endoscope system according to the present invention comprises an endoscope having the above light source device for an endoscope, an imaging device for imaging an observation object and outputting an image signal, and an imaging device for an observation object illuminated by broadband light. The first observation image is generated based on the image signal obtained through imaging, and the second observation image is generated based on the image signal obtained by imaging the observation target illuminated by the narrowband light by the imaging device. And an image processing unit.

  The light source control unit causes the third light and the fourth light to emit light with the same emission intensity by controlling the drive current applied to the third light emitting element and the drive current applied to the fourth light emitting element. Is preferred.

  And a third dichroic mirror for integrating the optical path integrated by the first dichroic mirror and the optical path integrated by the second dichroic mirror, and the light source control unit drives the first to fourth light emitting elements to Control for generating broad band light including light in the first to fourth wavelength bands, and driving the first light emitting element and the third light emitting element among the first to fourth light emitting elements to generate the first wavelength band light and the third light It is preferable to perform control to generate narrow band light including wavelength band light.

  The second light source further includes a fifth light emitting element that emits fifth light having a center wavelength on the longer wavelength side than the wavelength bands of the first light and the second light, and the light source control unit includes the first to fifth light emitting elements It is preferable to control to generate broadband light including the first to fourth wavelength band light and the fifth light by respectively driving

  The third light source further includes a sixth light emitting element that emits sixth light whose center wavelength is shorter than the wavelength bands of the third light and the fourth light, and the light source control unit includes the first to sixth light emitting elements Control to generate broadband light including the first to fourth wavelength band light, the fifth light, and the sixth light, and driving the first light emitting element, the first light emitting element, and the It is preferable to control to generate narrow band light including the first wavelength band light, the third wavelength band light and the sixth light by driving the three light emitting elements and the sixth light emitting element.

  Preferably, the first light and the second light are green light, the third light and the fourth light are blue light, the fifth light is red light, and the sixth light is violet light.

  The imaging device includes an imaging drive unit that causes the imaging device to perform an imaging operation for each frame period, and the light source control unit controls the first light emitting element and the second light emitting element for each frame period to obtain wide band light and narrow band light. It is preferable to generate light alternately.

  The light source device for an endoscope, the operation method thereof, and the endoscope system of the present invention can switch between broadband light and narrow band light instantaneously.

It is an external view of an endoscope system. It is a front view of the tip part of an endoscope. It is a block diagram which shows the electric constitution of an endoscope system. It is a figure showing composition of an image sensor. It is a graph which shows the light transmittance of a color filter. It is a figure which shows the structure of a light source part. It is a figure which shows the basic composition which consists of 1st green LED, 2nd green LED, and a 1st dichroic mirror. It is a figure which shows the optical characteristic of a 1st dichroic mirror, and the light intensity spectrum of 1st green light, 2nd green light, and red light. It is a graph which shows the light intensity spectrum of the 1st wavelength zone light which has the 1st wavelength zone between the 1st threshold of a 1st dichroic mirror among the wavelength zones of the 1st green light, and the 2nd threshold. It is a graph which shows the light intensity spectrum of the 2nd wavelength zone light which has the 2nd wavelength zone other than the 1st wavelength zone among the wavelength zones of the 2nd green light. It is a graph which shows the light intensity spectrum of the 1st wavelength zone light contained in broadband light, and the 2nd wavelength zone light. It is a graph which shows the light intensity spectrum of the 1st wavelength zone light contained in narrow zone light. It is a figure which shows the electric constitution of the 2nd light source of a multi-chip structure. It is a figure which shows the electric constitution of the 3rd light source of a multi-chip structure. It is a figure which shows the optical characteristic of a 2nd dichroic mirror, and the light intensity spectrum of purple light, 1st blue light, and 2nd blue light. It is a graph which shows the light intensity spectrum of the 3rd wavelength zone light which has the 3rd wavelength zone below the 3rd threshold of the 2nd dichroic mirror among the wavelength zones of the 1st blue light. It is a graph which shows the light intensity spectrum of the 4th wavelength zone light which has the 4th wavelength zone other than the 3rd wavelength zone among the wavelength zones of the 2nd blue light. It is a figure which shows the optical characteristic of a 3rd dichroic mirror. It is a graph which shows the light intensity spectrum of broadband light. It is a graph which shows the light intensity spectrum of narrow band light. It is a figure which shows light emission and imaging timing of illumination light. It is a flow chart explaining an operation of an endoscope system. It is a figure which shows the structure of the light source part in a comparative example. It is a figure which shows light emission and imaging timing of illumination light in a comparative example.

  In FIG. 1, an endoscope system 10 includes an electronic endoscope (hereinafter simply referred to as an endoscope) 11 for imaging an observation site in a living body as a subject, and an observation site based on an imaging signal obtained by imaging. Processor unit 12 for generating a display image of the light source, an endoscope light source unit (hereinafter simply referred to as a light source unit) 13 for supplying illumination light for irradiating the observation site to the endoscope 11, and a display unit for displaying the display image And a monitor 14. An operation input unit 15 such as a keyboard or a mouse is connected to the processor unit 12.

  The endoscope 11 connects the insertion unit 16 inserted into the digestive tract of a living body, the operation unit 17 provided at the proximal end of the insertion unit 16, and the endoscope 11 to the processor device 12 and the light source device 13 And a universal cord 18 for. The insertion part 16 is comprised by the front-end | tip part 19, the curved part 20, and the flexible tube part 21, and is connected in this order from the front end side.

  As shown in FIG. 2, two illumination windows 22 for irradiating illumination light to the observation site, an observation window 23 for taking in an image of the observation site, and an observation window 23 are cleaned on the tip surface of the tip portion 19 For this purpose, an air supply / water supply nozzle 24 for air supply / water supply, and a forceps outlet 25 for performing various treatments by projecting a treatment tool such as a forceps or an electric knife are provided. An image sensor 35 (see FIG. 3) is built in the back of the observation window 23.

  The bending portion 20 is composed of a plurality of connected bending pieces, and bends in the up, down, left, and right directions in accordance with the operation of the angle knob 17 a of the operation portion 17. By bending the bending portion 20, the tip 19 is oriented in a desired direction. The flexible tube portion 21 is flexible and can be inserted into a winding channel such as the esophagus or the intestine. The insertion unit 16 guides a drive signal for driving the imaging device 35, a communication cable for transmitting an imaging signal output from the imaging device 35, and illumination light supplied from the light source device 13 to the illumination window 22. The light guide 32 (see FIG. 3) is inserted.

  In addition to the angle knob 17a, the operation unit 17 is provided with a forceps opening 17b, an air / water supply button 17c, and a freeze button 17d as a still image acquisition operation unit. The forceps port 17b is an insertion port for inserting a treatment tool. The air supply / water supply button 17 c is operated when air supply / water supply is performed from the air supply / water supply nozzle 24. The freeze button 17 d is operated when acquiring a still image. The acquired still image is displayed on the monitor 14 by the controller 40 described later. Still images can also be recorded in a storage (not shown).

  A communication cable and a light guide 32 extended from the insertion portion 16 are inserted into the universal cord 18, and a connector 29 is attached to one end of the processor device 12 and the light source device 13 side. The connector 29 is a composite type connector including a communication connector 29a and a light source connector 29b. The communication connector 29 a is detachably connected to the processor device 12. One end of a communication cable is disposed on the communication connector 29a. The light source connector 29 b is detachably connected to the light source device 13. An incident end 32a (see FIG. 3) of the light guide 32 is disposed in the light source connector 29b.

  In FIG. 3, the light source device 13 includes a light source unit 30 and a light source control unit 31. The light source unit 30 outputs one of broadband light and narrow band light as illumination light based on control of the light source control unit 31. The illumination light output from the light source unit 30 is incident on the incident end 32 a of the light guide 32 of the endoscope 11.

  The endoscope 11 has a light guide 32, an irradiation lens 33, an objective optical system 34, an imaging device 35, and an imaging drive unit 36.

  The light guide 32 is a fiber bundle in which a plurality of optical fibers are bundled. When the light source connector 29 b is connected to the light source device 13, the incident end 32 a of the light guide 32 faces the emission end of the light source unit 30. The exit end of the light guide 32 is branched into two, and guides light to the two illumination windows 22 of the tip portion 19 respectively.

  The illumination lens 33 is disposed at the back of the illumination window 22. The illumination light supplied from the light source device 13 is guided by the light guide 32 to the irradiation lens 33 and irradiated from the illumination window 22 toward the observation site. The irradiation lens 33 is a concave lens and irradiates the illumination light emitted from the light guide 32 to a wide range of the observation site.

  The objective optical system 34 is disposed at the back of the observation window 23. A light image (return light) of the observation site illuminated by the illumination light enters the objective optical system 34 through the observation window 23. The objective optical system 34 causes return light to be incident on the imaging surface 35 a of the imaging device 35.

  The imaging device 35 is a color imaging device, captures an optical image of an observation target, and outputs an image signal. As shown in FIG. 4, on the imaging surface 35a of the imaging device 35, a plurality of pixels 38 for generating pixel signals by photoelectric conversion are formed. The pixels 38 are two-dimensionally arranged in a matrix in the row direction (X direction) and the column direction (Y direction).

  A color filter array 39 is provided on the light incident side of the imaging device 35. The color filter array 39 includes a blue (B) filter 39a, a green (G) filter 39b, and a red (R) filter 39c. One of these filters is disposed on each pixel 38. The color array of the color filter array 39 is a Bayer array, and the G filters 39b are arranged in a checkered manner every other pixel, and the B filters 39a and the R filters 39c are respectively formed in a square lattice on the remaining pixels. Is located in

  Hereinafter, the pixel 38 in which the B filter 39a is disposed is referred to as a B pixel, the pixel 38 in which the G filter 39b is disposed is referred to as a G pixel, and the pixel 38 in which the R filter 39c is disposed is referred to as an R pixel. In each pixel row of even (0, 2, 4,..., N-1), B pixels and G pixels are alternately arranged. In each of the odd (1, 3, 5,..., N) pixel rows, G pixels and R pixels are alternately arranged. Here, the pixel row indicates the pixels 38 for one row arranged in the row direction. The pixel column refers to one row of pixels 38 arranged in the column direction.

  The color filter array 39 has the spectral characteristics shown in FIG. The B filter 39a has a high light transmittance for a wavelength band of, for example, 380 nm to 560 nm. The G filter 39 b has high light transmittance for a wavelength band of 450 nm to 630 nm, for example. The R filter 39c has high light transmittance for a wavelength band of, for example, 580 nm to 760 nm.

  The imaging device 35 is driven by the imaging drive unit 36, receives the return light from the observation target illuminated by the illumination light by the plurality of pixels 38 via the color filter array 39, and outputs an image signal. The imaging device 35 outputs a BGR image signal including a B pixel signal, a G pixel signal, and an R pixel signal as an image signal.

  In the present embodiment, a complementary metal-oxide semiconductor (CMOS) image sensor is used as the imaging device 35. The CMOS image sensor generally performs an imaging operation by a rolling shutter method. In the rolling shutter system, the image pickup device 35 executes the signal readout by the “sequential readout system”. In the sequential readout method, signal readout is sequentially performed for every pixel row from the top pixel row “0” to the final pixel row “N” for all pixels 38.

  The imaging device 35 can execute “sequential reset method” and “collective reset method” as a reset method. In the sequential reset method, reset is performed sequentially for each pixel row from the top pixel row “0” to the final pixel row “N”. In the batch reset method, all pixel rows are simultaneously reset at once. In the present embodiment, the reset is performed sequentially by the reset method.

  The imaging device 35 includes a correlated double sampling (CDS) circuit, an automatic gain control (AGC) circuit, and an analog / digital (A / D) converter (all not shown). Etc. are also provided appropriately. The CDS circuit performs correlated double sampling processing on the pixel signal output from the pixel 38 to remove noise. The AGC circuit performs gain adjustment on the pixel signal subjected to the correlated double sampling process. The A / D converter converts the pixel signal whose gain has been adjusted by the AGC circuit into a digital signal of a predetermined number of bits and inputs the digital signal to the processor unit 12.

  Although the rolling shutter type CMOS image sensor is used as the imaging device 35 in the present embodiment, the present invention is not limited to this, and a global shutter type CMOS image sensor may be used. Furthermore, as the imaging device 35, a charge coupled device (CCD) image sensor may be used instead of the CMOS image sensor.

  The processor device 12 includes a controller 40 as a control unit, a DSP (Digital Signal Processor) 41, a frame memory 42, an image processing unit 43, and a display control unit 44.

  The controller 40 has a central processing unit (CPU), a read only memory (ROM) for storing control programs and setting data necessary for control, and a random access memory (RAM) as a working memory for loading the control programs. The CPU executes the control program to control each unit of the processor device 12, the light source control unit 31, and the imaging drive unit 36.

  The controller 40 drives the imaging drive unit 36 periodically (every frame period) and controls the light source control unit 31 to turn off the illumination light during the signal readout period and the reset period, and within the other periods. Turn on the illumination light. In the rolling shutter type imaging device 35, the exposure timing is sequentially shifted one pixel row at a time, but so-called simultaneousness is secured by the above-described lighting and extinguishing control.

  The DSP 41 performs signal processing such as pixel interpolation processing, gamma correction, white balance correction, and the like on the image signal input from the imaging device 35 via the communication connector 29 a. In the pixel interpolation process, the pixel interpolation process is performed on each of the B pixel signal, the G pixel signal, and the R pixel signal. The DSP 41 stores the image signal subjected to the signal processing in the frame memory 42 as image data every one frame period.

  The image processing unit 43 reads out the image data from the frame memory 42, performs predetermined image processing, and generates an observation image. The display control unit 44 converts the image generated by the image processing unit 43 into a video signal such as a composite signal or a component signal and outputs the video signal to the monitor 14.

  In FIG. 6A, the light source unit 30 includes the first light source 51, the second light source 52, the third light source 53, and the fourth light source 54, an LED (Light Emitting Diode) driving unit 55, and a focusing optical system 56. doing. The first to fourth light sources 51 to 54 are at least any of the purple LED 61, the first blue LED 62a, the second blue LED 62b, the first green LED 63a, the second green LED 63b, and the red LED 64, respectively. I have a baby. The purple LED 61 emits purple light LV. The first blue LED 62a emits the first blue light LB1. The second blue LED 62b emits the second blue light LB2. The first green LED 63a emits the first green light LG1. The second green LED 63b emits the second green light LG2. The red LED 64 emits red light LR.

  The condensing optical system 56 includes first to fourth collimator lenses 66 to 69, a condensing lens 70, and first to third dichroic mirrors (DM) 71 to 73.

  First, the basic configuration of the light source unit 30 will be described. The basic configuration of the light source unit 30 includes a first green LED 63a, a second green LED 63b, and a first DM 71, as shown in FIG. 6B. The optical path of the first green light LG1 emitted by the first green LED 63a and the optical path of the second green light LG2 emitted by the second green LED 63b are orthogonal to each other, and the first DM 71 is disposed at this intersection. The first green light LG1 is incident on one surface of the first DM 71 at an angle of 45 °, and the second green light LG2 is incident on the other surface at an angle of 45 °.

As shown in FIG. 7, the 1DM71 has two thresholds of a first threshold value lambda _a1 and the second threshold value lambda _a2 in the first and second green light LG1, LG2 within the wavelength band. The first and green lights LG1 and LG2 have wide emission wavelength bands. For example, the emission wavelength band of the first green light LG1 is 480 nm to 600 nm. Similarly, the emission wavelength band of the second green light LG2 is 480 nm to 600 nm. The first threshold λ _a1 is, for example, 530 nm. The second threshold λ _a2 is, for example, 550 nm. The first DM 71 transmits light having a first wavelength band between the first threshold λ _a1 and the second threshold λ _a2, and reflects light having a second wavelength band outside the first wavelength band.

  The first DM 71 transmits the first green light LG1 according to the above-described characteristics to generate the first wavelength band light La having the first wavelength band from the first green light LG1, as shown in FIG. 8A. Further, as shown in FIG. 8B, the first DM 71 generates the second wavelength band light Lb having the second wavelength band from the second green light LG2 by reflecting the second green light LG2. The first DM 71 integrates the optical path of the first wavelength band light La and the optical path of the second wavelength band light Lb.

  With the above-described configuration, the first green LED 63a and the second green LED 63b are turned ON by the light source unit 30 at the time of emission of wide band light described later, and as shown in FIG. 9A, the first wavelength band light La and the second wavelength Band light Lb is emitted from the first DM 71. The light of the first wavelength band is lost from the second wavelength band light Lb shown in FIG. 8B, and this lost portion is compensated by the multiplexing of the first wavelength band light La shown in FIG. 8A. By combining the first wavelength band light La and the second wavelength band light Lb by the first DM 71, a spectrum similar to that of the first and second green light LG1 and LG2 can be obtained.

  Further, at the time of light emission of narrow band light described later, of the first green LED 63a and the second green LED 63b, the first green LED 63a is turned ON by the light source unit 30, and the second green LED 63b is turned OFF. In this case, as shown in FIG. 9B, the first wavelength band light La is emitted from the first DM 71.

  Next, the specific configuration of the light source unit 30 will be described. The first light source 51 is an LED light source of a single chip configuration in which one first green LED 63 a is mounted on one substrate 60. The second light source 52 is a multi-chip LED light source in which the second green LED 63 b and the red LED 64 are mounted on one substrate 60. The third light source 53 is a multi-chip LED light source in which the purple LED 61 and the first blue LED 62 a are mounted on one substrate 60. The fourth light source 54 is an LED light source of a single chip configuration in which one second blue LED 62 b is mounted on one substrate 60.

  The first green LED 63a and the second green LED 63b are green light emitting elements having the same light emission characteristics. The first blue LED 62a and the second blue LED 62b are blue light emitting elements having the same light emission characteristics. The "same emission characteristics" means that the wavelength bands are almost equal. The difference in wavelength band corresponds, for example, to the difference in spectral width (eg, full width at half maximum). For two lights, the same wavelength band means, for example, that the difference in spectral width is 10% or less.

  The first green LED 63 a corresponds to the “first light emitting element” in the claims. The second green LED 63 b corresponds to the “second light emitting element” in the claims. The first blue LED 62 a corresponds to the “third light emitting element” in the claims. The second blue LED 62 b corresponds to the “fourth light emitting element” in the claims. The red LED 64 corresponds to the “fifth light emitting element” in the claims. The purple LED 61 corresponds to the “sixth light emitting element” in the claims.

  As shown in FIG. 10A, the second light source 52 is configured by a cathode common connection in which the cathode terminal of the second green LED 63b and the cathode terminal of the red LED 64 are connected. Similarly, as shown in FIG. 10B, the third light source 53 is configured by a cathode common connection in which the cathode terminal of the violet LED 61 and the cathode terminal of the first blue LED 62a are connected.

  Therefore, with the second light source 52, the drive current that the light source control unit 31 applies between the anode terminal and the cathode terminal of the second green LED 63b via the LED driving unit 55, and the anode terminal and the cathode terminal of the red LED 64 The second green LED 63 b and the red LED 64 can be individually turned ON / OFF by individually controlling the drive current to be applied during the period. Similarly, the third light source 53 is a drive current that the light source controller 31 supplies between the anode terminal and the cathode terminal of the violet LED 61 via the LED driver 55, and the anode terminal and the cathode terminal of the first blue LED 62a. The purple LED 61 and the first blue LED 62a can be individually turned ON / OFF by individually controlling the driving current to be applied between them.

  The violet LED 61 emits, for example, violet light LV having an emission wavelength band of 380 nm to 420 nm and a center wavelength of 405 nm. The first blue LED 62a emits, for example, a first blue light LB1 having an emission wavelength band of 420 nm to 500 nm and a center wavelength of 460 nm. Similarly, the second blue LED 62b emits a second blue light LB2 having an emission wavelength band of 420 nm to 500 nm and a center wavelength of 460 nm. The red LED 64 emits, for example, red light LR having an emission wavelength band of 600 nm to 650 nm and a center wavelength of 620 nm to 630 nm. The first green LED 63a emits the first green light LG1 having an emission wavelength band of 480 nm to 600 nm as described above. Similarly, the second green LED 63b emits a second green light LG2 having an emission wavelength band of 480 nm to 600 nm.

  The central wavelength of the purple light LV is shorter than the wavelength band of the first and second blue lights LB1 and LB2. The central wavelengths of the first and second blue lights LB1 and LB2 are shorter than the wavelength bands of the first and second green lights LG1 and LG2. The central wavelength of the red light LR is on the longer wavelength side than the wavelength band of the first and second green light LG1 and LG2. The light of each color may have the same or different central wavelength and peak wavelength.

  The first green LED 63a and the second green LED 63b are respectively configured by an excitation blue LED (not shown) as an excitation light emitting element and a green phosphor (not shown). The blue LED for excitation emits, for example, excitation light having a wavelength band of 450 nm to 460 nm. The green phosphor emits broad-band green fluorescence by being excited by excitation light.

  The LED drive unit 55 is drive-controlled by the light source control unit 31, and drive current for the violet LED 61, the first blue LED 62a, the second blue LED 62b, the first green LED 63a, the second green LED 63b, and the red LED 64 independently. give. The light source control unit 31 can independently set drive currents applied to the purple LED 61, the first blue LED 62a, the second blue LED 62b, the first green LED 63a, the second green LED 63b, and the red LED 64. The violet LED 61, the first blue LED 62a, the second blue LED 62b, the first green LED 63a, the second green LED 63b, and the red LED 64 emit light with an emission intensity corresponding to the setting value of the drive current set by the light source control unit 31.

  In the present embodiment, the light source control unit 31 controls the drive current applied to the first green LED 63a and the drive current applied to the second green LED 63b to generate the first green light LG1 and the second green light LG1. The green light LG2 is emitted with the same emission intensity. In addition, the light source control unit 31 controls the drive current applied to the first blue LED 62a and the drive current applied to the second blue LED 62b, thereby the first blue light LB1 and the second blue light LB2 Light with the same light emission intensity. In addition, "the same luminescence intensity" means that the difference of the luminescence intensity which arises by the individual difference of LED is accepted. For example, with respect to two lights respectively emitted from two LEDs, the same emission intensity means that the difference in emission intensity is 10% or less.

  The first collimator lens 66 condenses the first green light LG1 as the first light emitted from the first light source 51, and emits the collected first green light LG1 as parallel light. The second collimator lens 67 condenses the second green light LG2 as the second light emitted from the second light source 52 and the red light LR as the fifth light, and collects the collected second green light LG2 The red light LR is emitted as parallel light. The third collimator lens 68 condenses the purple light LV as the sixth light emitted from the third light source 53 and the first blue light LB1 as the third light, and collects the collected purple light LV and the first blue light Light LB1 is emitted as parallel light. The fourth collimator lens 69 condenses the second blue light LB2 as the fourth light emitted from the fourth light source 54, and emits the condensed second blue light LB2 as parallel light.

  The light collimated by the first to fourth collimator lenses 66 to 69 may not be completely parallel light, as long as it can be regarded as substantially parallel. The parallelism of the parallel light is preferably higher as the distance from each lens position of the first to fourth collimator lenses 66 to 69 to the position of the condenser lens 70 is longer.

  The light path of the first green light LG1 emitted from the first collimator lens 66 and the light path of the second green light LG2 and the red light LR emitted from the second collimator lens 67 are orthogonal to each other. Is arranged. The first green light LG1 is incident on one surface of the first DM 71 at an angle of 45 °, and the second green light LG2 and the red light LR are incident on the other surface at an angle of 45 °.

The first DM 71 has two thresholds of the first threshold λ _a1 and the second threshold λ _a2 as described above, and generates the first wavelength band light La by transmitting the first green light LG 1, By reflecting the second green light LG2, a second wavelength band light Lb is generated. Further, as shown in FIG. 7, the first DM 71 reflects almost all the red light LR from the second light source 52. The first DM 71 integrates the optical path of the first wavelength band light La and the optical path of the second wavelength band light Lb and the red light LR.

  The optical paths of the first blue light LB1 and the purple light LV emitted from the third collimator lens 68 and the optical path of the second blue light LB2 emitted from the fourth collimator lens 69 are orthogonal to each other. Is arranged. The violet light LV and the first blue light LB1 are incident at an angle of 45 ° on one surface of the second DM 72, and the second blue light LB2 is incident at an angle of 45 ° on the other surface.

The second DM 72 has one third threshold λ _b in the wavelength band of the first and second blue lights LB1 and LB2. For example, as shown in FIG. 11, the second DM 72 has a third threshold λ _b at 460 nm. That is, the 2DM72 transmits light of the third threshold value lambda _b longer wavelengths, and reflects the light of the third threshold value lambda _b wavelengths below.

The 2DM72 is the above characteristics, by reflecting the first blue light LB1, as shown in FIG. 12A, the third wavelength band light Lc having the third wavelength band third threshold lambda _b first blue Generate from light LB1. Also, the 2DM72, by transmitting the second blue light LB2, as shown in FIG. 12B, the fourth wavelength band light Ld having a third threshold value lambda _b is larger than the fourth wavelength band from the second blue light LB2 Generate The second DM 72 reflects the purple light LV from the third light source 53 as it is. The second DM 72 integrates the optical paths of the violet light LV and the third wavelength band light Lc with the optical path of the fourth wavelength band light Ld.

  The optical path integrated by the first DM 71 and the optical path integrated by the second DM 72 are orthogonal to each other, and the third DM 73 is disposed at this intersection point. The first wavelength band light La, the second wavelength band light Lb, and the red light LR are incident at an angle of 45 ° to one surface of the third DM 73, and the purple light LV, the third wavelength band light Lc, and the other surface The fourth wavelength band light Ld is incident at an angle of 45 °.

The third DM 73 has a fourth threshold λ _c at about 490 nm, as shown in FIG. The 3DM73 transmits light of a fourth threshold value lambda wavelength longer than _c, and reflects the light of the fourth threshold value lambda _c wavelengths below. With this configuration, the third DM 73 integrates the optical path integrated by the first DM 71 and the optical path integrated by the second DM 72.

  The light source control unit 31 generates broadband light (also referred to as white light or normal light) by turning on all of the first to fourth light sources 51 to 54. Specifically, when the first light source 51 is turned on, the first wavelength band light La is incident on the third DM 73. When the second light source 52 is turned on, the second wavelength band light Lb and the red light LR are incident on the third DM 73. When the third light source 53 is turned on, the purple light LV and the third wavelength band light Lc are incident on the third DM 73. When the fourth light source 54 is turned on, the fourth wavelength band light Ld is incident on the third DM 73. As a result, the first wavelength band light La, the second wavelength band light Lb, the red light LR, the violet light LV, the third wavelength band light Lc, and the fourth wavelength band light Ld are multiplexed by the third DM 73, as shown in FIG. 14A. The broadband light shown in FIG.

Here, since the loss portion (first wavelength band) of the second wavelength band light Lb is compensated by the multiplexing of the first wavelength band light La, in the wide band light shown in FIG. A spectrum similar to that of the two green lights LG1 and LG2 is reproduced. Similarly, from the fourth wavelength band light Ld, as shown in FIG. 12B, light in the third wavelength band equal to or less than the third threshold λ _b of the second DM 72 is lost, but this lost portion is shown in FIG. 12A. Since the third wavelength band light Lc is compensated for by multiplexing, the spectrum similar to the first and second blue lights LB1 and LB2 is reproduced in the wide band light shown in FIG. 14A.

  In the present embodiment, broadband light is generated by setting all of the first to fourth light sources 51 to 54 to ON, but the present invention is not limited thereto. For example, the first to third light sources 51 to 53 Alternatively, the fourth light source 54 may be turned off.

  In addition, the light source control unit 31 turns on the first light source 51 and the third light source 53 and turns off the second light source 52 and the fourth light source 54 to generate narrow band light. As a result, the violet light LV, the first blue light LB1, and the first green light LG1 are combined by the third DM 73, and narrow band light shown in FIG. 14B is generated.

  Among the narrow band light, the purple light LV and the third wavelength band light Lc are light of a wavelength band optimum for observing a superficial blood vessel located at a shallow position from the mucosal surface. On the other hand, the first wavelength band light La is light of a wavelength band optimum for observation of a middle deep blood vessel located at a position deeper than the superficial blood vessel. Note that the long wavelength component of the first blue light LB1 reduces the contrast between the mucous membrane and the blood vessel, and thus is prevented from being supplied to the light guide 32 by transmitting the second DM 72.

  The condensing lens 70 is disposed in the vicinity of the incident end 32 a of the light guide 32, and condenses the broadband light or the narrow band light emitted from the third DM 73 so as to be incident on the incident end 32 a of the light guide 32.

  Endoscope system 10 is capable of multiple viewing modes. The multi-observation mode is an observation mode in which a normal observation image using wide band light and a blood vessel-emphasized observation image using narrow band light are simultaneously displayed on the monitor 14.

  The normal observation image is an image captured by broadband light with high color rendering. As described above, the blood vessel-emphasized observation image uses narrow band light containing a large amount of light components in a specific wavelength band where the absorbance to blood hemoglobin is high. Image. The normal observation image corresponds to the “first observation image” in the claims, and the blood vessel-emphasized observation image corresponds to the “second observation image” in the claims.

In the multi observation mode, the controller 40 controls the light source control unit 31 and the imaging driving unit 36 to match the timing of emitting the wide band light and the narrow band light with the frame period of the imaging device 35 as shown in FIG. . Specifically, the controller 40 emits wide band light or narrow band light in a period between the completion of the sequential reset by the imaging device 35 and the start of the signal readout. Therefore, the period from the completion of sequential reset to the start of signal readout is the exposure period. The exposure period, the signal readout period, and the reset period are provided within one frame period T _F.

The light source control unit 31 emits wide band light or narrow band light in accordance with the exposure period of the imaging device 35, and turns off wide band light and narrow band light in the other periods (signal readout period and reset period). Period for emitting broadband light or narrow band light is lit period T _A, other periods are off period T _B (see FIG. 15). That is, in synchronism with the frame cycle is repeated a lighting period T _A and extinction period T _B is.

The light source control unit 31 may, in one frame period T _F, all of the first to fourth light sources 51 to 54 is turned ON in the lighting period T _A, light-off period T _B in all of the first to fourth light sources 51 to 54 Turn off. In the next frame period T _F, the light source control unit 31 includes a first light source 51 a third light source 53 and the ON Toshikatsu second light source 52 and the fourth light source 54 remains OFF the lighting period T _A, Off all of the first to fourth light sources 51 to 54 and OFF in the period T _B. As a result, the broadband light having the light intensity spectrum shown in FIG. 14A and the narrowband light having the light intensity spectrum shown in FIG. 14B are alternately emitted from the light source unit 30 and the light guide 32 via the condenser lens 70. Supplied to

The imaging device 35, the lighting period T _A of the broadband light, receiving violet light LV from the observation target that is illuminated by broadband light, a third wavelength band light Lc, and the return light of the fourth wavelength band light Ld in B pixel and outputs the B pixel signals for subsequent off period T _B. Similarly, the imaging element 35 receives the return light of the first wavelength band light La and the second wavelength band light Lb from the observation target in the lighting period T _A of the wide band light by the G pixel, and the light off period T after that. Output G pixel signal to _B. The imaging element 35, the lighting period T _A of the broadband light, the return light of the red light LR from the observation target is received by the R pixel, and outputs the R pixel signals for subsequent off period T _B.

The imaging device 35, the lighting period T _A of the narrow band light, receives the return light violet light LV and the third wavelength band light Lc from the observation object illuminated by narrowband light in the B pixel, a subsequent OFF period and it outputs the B pixel signals to T _B. Similarly, the imaging device 35, the lighting period T _A of the narrow-band light, the first wavelength band light La of the return light from the observation target is received by the G pixel, then the off period T _B to output the G pixel signal Do. Although the imaging element 35 can also output an R pixel signal, since the R pixel signal is not used to generate a blood vessel enhanced observation image, only the B pixel signal and the G pixel signal may be output.

  As described above, all of the first to fourth light sources 51 to 54 are turned off in the signal readout period in which the signal readout is performed by the sequential readout method and the reset period in which the reset operation is performed by the sequential reset method. . Although the imaging device 35 is a rolling shutter system, since the light emission of the first to fourth light sources 51 to 54 is performed within a period in which all the pixel rows can receive light, the exposure period in which the illumination light is actually exposed is , The same for all pixel rows. Therefore, so-called simultaneousness is secured by the above-mentioned lighting and extinguishing control.

  The image processing unit 43 generates a normal observation image based on the B pixel signal, the G pixel signal, and the R pixel signal which are output when the observation target is illuminated with the wide band light.

  Further, the image processing unit 43 generates a blood vessel-emphasized observation image based on the B pixel signal and the G pixel signal output at the time of illumination of the observation target with narrow band light. The image processing unit 43 extracts the area of the surface blood vessel in the image based on the B pixel signal in the image data, for example, in order to emphasize the surface blood vessel, and performs edge enhancement processing on the extracted surface blood vessel area. Apply etc. Then, the B pixel signal subjected to the edge enhancement processing is synthesized with a full color image generated based on the BGR image signal. The same process may be performed on middle and deep blood vessels in addition to superficial blood vessels. In the case of emphasizing the deep blood vessel, the region of the deep blood vessel is extracted from the G pixel signal containing much information of the deep blood vessel, and the contour emphasis processing is performed on the extracted deep blood vessel region.

  The display control unit 44 causes the monitor 14 to display the normal observation image and the blood vessel emphasis observation image generated by the image processing unit 43 side by side. The display control unit 44 causes the monitor 14 to sequentially display the normal observation image and the blood vessel emphasis observation image each time they are generated. Thereby, the normal observation moving image and the blood vessel emphasis observation moving image are displayed on the monitor 14. When the image processing unit 43 generates a blood vessel-emphasized observation image using only the B pixel signal and the G pixel signal without using the R pixel signal, the display control unit 44 selects the B pixel signal for the B channel and G of the monitor 14. The G pixel signal may be assigned to the channel and the R channel of the monitor 14 may be assigned.

  When the freeze button 17d is operated during display of the normal observation moving image and the blood vessel-emphasized observation moving image, the controller 40 freezes the image display by displaying each image immediately before the operation of the freeze button 17d on the monitor 14. When the freeze button 17d is operated again, the controller 40 resumes the moving image display.

  Next, the operation of the endoscope system 10 will be described along the flowchart shown in FIG. When a user such as a doctor activates the endoscope system 10 to perform endoscope diagnosis, the multi observation mode is executed (S11), and the imaging device 35 starts an imaging operation.

The light source control unit 31 turns on all of the first to fourth light sources 51 to 54 in one frame period _TF . Thereby, the broadband light is irradiated to the observation site (S12). Thereafter, signal readout and sequential reset are executed by the imaging device 35 (S13). While the signal readout and the sequential reset are performed by the imaging device 35, the light source control unit 31 turns off all of the first to fourth light sources 51 to 54. The imaging device 35 outputs an image signal by imaging the observation site illuminated by the broadband light and inputs the image signal to the DSP 41. The DSP 41 performs signal processing such as pixel interpolation processing, gamma correction, white balance correction, and the like on the image signal to obtain image data, which is stored in the frame memory 42.

When the sequential resetting by the imaging device 35 is completed, the light source control unit 31 turns on the first light source 51 and the third light source 53 in the next one frame cycle _TF , and the second light source 52 and the fourth light source 54 Leave OFF. Thereby, narrow band light is irradiated to an observation part (S14). Thereafter, signal readout and sequential reset are executed by the imaging device 35 (S15). During this time, the light source control unit 31 turns off all of the first to fourth light sources 51 to 54. The imaging device 35 outputs an image signal by imaging the observation site illuminated by the narrow band light and inputs the image signal to the DSP 41. The DSP 41 performs signal processing on the image signal as described above to obtain image data, which is stored in the frame memory 42.

  The image processing unit 43 generates a normal observation image and a blood vessel emphasis observation image based on the image data stored in the frame memory 42, and the display control unit 44 displays the normal observation image and the blood vessel emphasis observation image on the monitor 14. Ru. (S16).

  The controller 40 determines whether or not it is in the freeze operation state (S17). In the freeze operation state, the user operates the freeze button 17 d to freeze the image display of the normal observation moving image and the blood vessel enhanced observation moving image displayed on the monitor 14 by repeatedly executing the steps S 12 to S 16. The situation is When the freeze button 17d is operated and the freeze operation state is established (YES in S17), the controller 40 freezes the image display of the normal observation moving image and the blood vessel emphasis observation moving image (S18), and the normal observation image and the blood vessel emphasis observation image It is displayed on the monitor 14. When the freeze button 17d is operated again, the freeze operation state is released and the moving image display is resumed. The above steps S12 to S18 in the multi-observation mode are repeatedly executed until the diagnosis is completed (YES in S19).

  Conventionally, in order to obtain a normal observation image and a blood vessel-emphasized observation image, a dichroic mirror is inserted and removed, and thereby broadband light and narrowband light can not be switched in accordance with the frame period, so that broadband light is emitted. An observation mode for acquiring a normal observation image and an observation mode for emitting a narrow band light to acquire a blood vessel-emphasized observation image are separately provided. Therefore, the user needs to switch between the two observation modes in order to compare the normal observation image and the blood vessel-emphasized observation image, and is obliged to observe the normal observation image and the blood vessel emphasis observation image having different acquisition times. It was not. However, in the present embodiment, since the broadband light and the narrow band light can be instantaneously switched according to the frame period of the imaging device by lighting control of the light source, the user can observe one multi observation without switching the observation mode. It is possible to observe the normal observation image and the blood vessel-emphasized observation image acquired at approximately the same time in the mode.

Although the light reflectance and the light transmittance of the first DM 71 change from 100% to 0% at the first threshold λ _a1 in the above embodiment, strictly speaking, the light reflectance and the light transmittance of the first DM 71 are 100% to 0 at the first threshold λ _a1. It does not necessarily change to%, and a change from 100% to 0% requires, for example, about 50 nm. Therefore, the wavelength and the light reflectance of the 1DM71 and light transmittance coincides, namely the wavelength of light reflectance and light transmittance is approximately 50% may be used as the first threshold value lambda _a1. The same applies to the second threshold λ _a2 , the third threshold λ _{b of} the second DM 72, and the fourth threshold λ _c of the third DM 73.

  The arrangement of the first to third DMs 71 to 73 is not limited to the arrangement shown in the above embodiment. For example, the third DM 73 may be provided between the second collimator lens 67 and the first DM 71. The third DM 73 in this case integrates the optical paths of the second wavelength band light Lb and the red light LR with the optical path integrated by the second DM 72. Therefore, the third DM 73 causes the violet light LV, the third wavelength band light Lc, the second wavelength band light Lb, and the red light LR to be incident on the first DM 71. The first DM 71 integrates the optical path integrated by the third DM 73 with the optical path of the first wavelength band light La.

  In the above embodiment, the light source control unit 31 controls the drive current applied to the first green LED 63a and the second green LED 63b to emit the first green light LG1 and the second green light LG2 in the same manner. Although light is emitted at an intensity, the light emission intensity of the first green light LG1 and the light emission intensity of the second green light LG2 may be made different. Similarly, the light source control unit 31 controls the drive current applied to the first blue LED 62a and the second blue LED 62b to emit the first blue light LB1 and the second blue light LB2 with the same emission intensity. However, the emission intensity of the first blue light LB1 and the emission intensity of the second blue light LB2 may be made different. For example, by setting the emission intensity of the first green light LG1 to be larger than the emission intensity of the second green light LG2 and setting the emission intensity of the first blue light LB1 to be larger than the emission intensity of the second blue light LB2, Contrast can be further enhanced.

[Comparative example]
The comparative example will be described below. The comparative example is different from the above embodiment in the configuration of the light source unit and the lighting control of the light source control unit.

  As shown in FIG. 17, in the light source unit 100 of the comparative example, a first half mirror (HM) 101 is provided in place of the first DM 71 provided in the light source unit 30 of the above embodiment. Further, in the light source unit 100 of the comparative example, a first band pass filter (BPF) 102 is added between the first HM 101 and the first collimator lens 66. Similarly, in the light source unit 100 of the comparative example, a second HM 103 is provided instead of the second DM 72 of the above embodiment. In addition, a second BPF 104 is added between the second HM 103 and the third collimator lens 68. The other configuration is the same as that of the above embodiment.

The first HM 101 is an optical member having a reflectance and a transmittance of approximately 50%. The first BPF 102 has two thresholds of the first threshold λ _a1 and the second threshold λ _a2 similar to the first DM 71, and transmits the wavelength band between the first threshold λ _a1 and the second threshold λ _a2 , Absorb or reflect other wavelength bands.

  When the first light source 51 is turned on due to the characteristics of the first HM 101 and the first BPF 102 as described above, a portion of the wavelength band component of the first green light LG1 passes through the first BPF 102 to produce the first wavelength band light La. Is generated. The light amount of the first wavelength band light La is halved by passing through the first HM 101 and enters the third DM 73.

  When the second light source 52 is turned on, the second green light LG2 and the red light LR are reflected by the first HM 101 so that the light amount is halved and enters the third DM 73.

The second HM 103 is an optical member having a reflectance and a transmittance of approximately 50%. The 2BPF104 has a third threshold value lambda _b of one similar to the first 2DM72, is transmitted through the third or less of the wavelength band threshold lambda _b, to absorb or reflect a wavelength band other than that.

  Due to the characteristics of the second HM 103 and the second BPF 104 as described above, when the third light source 53 is turned on, a portion of the wavelength band component of the first blue light LB 1 is transmitted through the second BPF 104 to obtain the third wavelength band light Lc. Is generated. The third wavelength band light Lc is reflected by the second HM 103 so that the amount of light is halved and enters the third DM 73. In addition, after passing through the second BPF 104, the purple light LV is reflected by the second HM 103 to reduce the light quantity to half and enter the third DM 73.

  When the fourth light source 54 is turned on, the second blue light LB2 is half transmitted by the second HM 103 and enters the third DM 73.

  In the comparative example, the light source control unit 31 turns on the second light source 52 and the fourth light source 54 and turns off the first light source 51 and the third light source 53 as illustrated in FIG. 18 when emitting broadband light. . As a result, broadband light is generated in which the second green light LG2 and the red light LR from the second light source 52 and the second blue light LB from the fourth light source 54 are combined.

  Further, when narrow band light is emitted, the light source control unit 31 turns on the first light source 51 and the third light source 53 and turns off the second light source 52 and the fourth light source 54. As a result, the first green light LG1 from the first light source 51 is transmitted through the first BPF 102, and the first blue light LB1 from the fourth light source 54 is transmitted through the second BPF 104. Thus, narrow band light in which the third wavelength band light Lc generated thereby and the purple light LV from the fourth light source 54 are combined is generated. The other control is the same as that of the above embodiment, and is thus omitted.

  In this comparative example, although the broadband light has its light quantity reduced by half by the half mirror, it does not cut off a part of the wavelength band as in the above embodiment, so it has a highly continuous wavelength band.

  Further, in the comparative example, all of the first to fourth light sources 51 to 54 may be turned ON when the wide band light is emitted. As a result, in addition to the second blue light LB2, the second green light LG2, and the red light LR, the wide band light in which the purple light LV, the first wavelength band light La, and the third wavelength band light Lc are combined is a light guide Supplied to By using such broadband light, the blood vessel contrast of a normal observation image can be increased. In this case, based on the control of the light source control unit 31, the blood vessel is configured by increasing the set value of the drive current given to the first green LED 63a and the set value of the drive current given to the violet LED 61 and the first blue LED 62a. Contrast can be further enhanced.

  In the embodiment and the comparative example, one second green LED 63 b and one red LED 64 are provided on one substrate 60 in the second light source 52, but two or more LEDs may be provided. Similarly, in the third light source 53, one violet LED 61 and one first blue LED 62a are provided on one substrate 60, but two or more LEDs may be provided.

  In the above embodiment, the second light source 52 is connected to the cathode terminal of the second green LED 63b and the cathode terminal of the red LED 64, but instead of the second light source 52, the anode terminal of the second green LED 63b and the red LED 64 You may connect with an anode terminal. The cathode terminals of the second green LED 63b and the red LED 64 may be connected to each other, and the anode terminals of the second green LED 63b and the red LED 64 may be connected to each other. Similarly, in the third light source 53, the cathode terminal of the violet LED 61 and the cathode terminal of the first blue LED 62a are connected, but instead, the anode terminal of the violet LED 61 and the anode terminal of the first blue LED 62a are connected. You may connect it. The cathode terminals of the purple LED 61 and the first blue LED 62a may be connected to each other, and the anode terminals of the purple LED 61 and the first blue LED 62a may be connected to each other.

  The second light source 52 may have a single chip configuration in which one second green LED 63 b and one red LED 64 are provided on different substrates, instead of the multi-chip configuration. In this case, a dichroic mirror that integrates the optical path of the second green light LG2 emitted by the second green LED 63b and the optical path of the red light LR emitted by the red LED 64 is added. Similarly, the third light source 53 may have a single chip configuration in which one purple LED 61 and one first blue LED 62a are provided on different substrates, instead of the multichip configuration. In this case, a dichroic mirror is added which integrates the light path of the purple light LV emitted by the purple LED 61 and the light path of the first blue light LB1 emitted by the first blue LED 62a.

In the above embodiment and the comparative example, the light source control unit 31 is a lighting period T _A is in accordance with the exposure period of the imaging device 35, the lighting period T _A can be appropriately changed as long as the exposure period. For example, the light source control unit 31, within the exposure period of the imaging device 35, combined the start timing of the lighting time T _A to start timing of the exposure period, and earlier than the end timing of the end timing of the exposure period of the lighting period T _A by Rukoto, it may be shortening the lighting period T _a. Further, the start timing of the lighting time period T _A was fed than the start timing of the exposure period, and by matching the end timing of the lighting time T _A to the end timing of the exposure period, may be shortened lighting periods T _A.

  In the embodiment and the comparative example, the endoscope system 10 can execute the multi observation mode. However, in addition to the multi observation mode, the normal light observation mode and the blood vessel emphasis observation mode may be possible. The normal light observation mode is an observation mode in which a normal observation image is displayed on the monitor 14 by using broadband light as illumination light. The blood vessel emphasis observation mode is an observation mode in which a blood vessel emphasis observation image is displayed on the monitor 14 by using narrow band light as illumination light. These observation modes can be selected by the operation input unit 15 or the like.

  In the embodiment and the comparative example, the primary color filter array 39 is provided in the imaging device 35. However, a complementary color filter array may be provided instead.

Reference Signs List 10 endoscope system 11 endoscope 12 processor device 13 light source device 14 monitor 15 operation input unit 16 insertion unit 17 operation unit 17 a angle knob 17 b forceps port 17 c air / water supply button 17 d freeze button 18 universal cord 19 tip 20 curved Section 21 flexible tube section 22 illumination window 23 observation window 24 air / water nozzle 25 insulator outlet 29 connector 29a communication connector 29b light source connector 30, 100 light source section 31 light source control section 32 light guide 32a incident end 33 irradiation lens 34 Objective optical system 35 Image pickup device 35a Image pickup surface 36 Image pickup driver 38 pixels 39 Color filter array 39a Blue filter 39b Green filter 39c Red filter 40 Controller 41 DSP
42 Frame Memory 43 Image Processing Unit 44 Display Control Unit 51 First Light Source 52 Second Light Source 54 Fourth Light Source 55 LED Driving Unit 56 Focusing Optical System 61 Purple LED
62a 1st blue LED
62b 2nd blue LED
63a 1st green LED
63b 2nd green LED
64 red LED
66 1st collimator lens 67 2nd collimator lens 68 3rd collimator lens 69 4th collimator lens 70 condensing lens 71 1st dichroic mirror 72 2nd dichroic mirror 73 3rd dichroic mirror 101 1st half mirror 102 1st band pass filter 103 second half mirror 104 second band pass filter

Claims (9)

A first light source having a first light emitting element that emits a first light;
A second light source having a second light emitting element that emits a second light having the same wavelength band as the first light;
A third light source having a third light emitting element that emits a third light whose center wavelength is shorter than the wavelength bands of the first light and the second light;
A fourth light source having a fourth light emitting element that emits fourth light having the same wavelength band as the third light;
A first dichroic mirror having a first threshold and a second threshold within wavelength bands of the first light and the second light, the first dichroic mirror having a first wavelength band between the first threshold and the second threshold One wavelength band light is generated from the first light, and a second wavelength band light having a second wavelength band outside the first wavelength band is generated from the second light, and an optical path of the first wavelength band light and the above A first dichroic mirror that integrates the light path of the second wavelength band light;
A third wavelength band light having a third threshold in a wavelength band of the third light and the fourth light and having a third wavelength band less than the third threshold is generated from the third light, and the third light is generated. A second dichroic mirror that generates fourth wavelength band light having a fourth wavelength band larger than a threshold from the fourth light, and integrates the optical path of the third wavelength band light and the optical path of the fourth wavelength band light;
Control to drive the first light emitting element and the second light emitting element to generate wide band light including the first wavelength band light and the second wavelength band light, the first light emitting element and the second light emitting element of the first and the light-emitting element is driven, have rows and a control to generate the narrow-band light including the first wavelength band, and a drive current applied to the first light emitting element, the second A light source control unit configured to emit the first light and the second light with the same light emission intensity by controlling a drive current applied to the light emitting element ;
A light source device for an endoscope, comprising: The light source control unit controls the drive current applied to the third light emitting element and the drive current applied to the fourth light emitting element to make the third light and the fourth light the same. The light source device for an endoscope according to claim 1 , wherein light is emitted at a light emission intensity. And a third dichroic mirror that integrates an optical path integrated by the first dichroic mirror and an optical path integrated by the second dichroic mirror,
The light source control unit controls the first to fourth light emitting elements to generate broadband light including the first to fourth wavelength bands, and the first to fourth light emitting elements. The control according to claim 1 or 2 , wherein the first light emitting element and the third light emitting element are driven to generate narrow band light including the first wavelength band light and the third wavelength band light. Light source device for endoscopes. The second light source further includes a fifth light emitting element that emits fifth light whose center wavelength is on the longer wavelength side than the wavelength bands of the first light and the second light,
The light source control part, the first through fifth respectively to drive the light emitting device, according to claim 3 for controlling to generate a broadband light including the first to fourth wavelength band and the fifth light Light source device for endoscopes. The third light source further includes a sixth light emitting element that emits sixth light having a center wavelength shorter than that of the wavelength bands of the third light and the fourth light,
The light source control unit controls the first to sixth light emitting elements to generate broadband light including the first to fourth wavelength band light, the fifth light, and the sixth light; Said 1st-
Among the sixth light emitting elements, the first light emitting element, the third light emitting element, and the sixth light emitting element are driven to generate the first wavelength band light, the third wavelength band light, and the sixth light. The light source device for endoscopes according to claim 4 which performs control which generates narrow band light including. According the first light and the second light is green light, the third light and the fourth light is blue light, the fifth light is red light, the sixth light is violet light Item 6. A light source device for endoscope according to item 5 . A first light source having a first light emitting element that emits a first light;
A second light source having a second light emitting element that emits a second light having the same wavelength band as the first light;
A third light source having a third light emitting element that emits a third light whose center wavelength is shorter than the wavelength bands of the first light and the second light;
A fourth light source having a fourth light emitting element that emits fourth light having the same wavelength band as the third light;
A first dichroic mirror having a first threshold and a second threshold within wavelength bands of the first light and the second light, the first dichroic mirror having a first wavelength band between the first threshold and the second threshold One wavelength band light is generated from the first light, and a second wavelength band light having a second wavelength band outside the first wavelength band is generated from the second light, and an optical path of the first wavelength band light and the above A first dichroic mirror that integrates the light path of the second wavelength band light;
A third wavelength band light having a third threshold in a wavelength band of the third light and the fourth light and having a third wavelength band less than the third threshold is generated from the third light, and the third light is generated. A second dichroic mirror that generates fourth wavelength band light having a fourth wavelength band larger than a threshold from the fourth light, and integrates the optical path of the third wavelength band light and the optical path of the fourth wavelength band light;
In a method of operating a light source device for an endoscope, comprising:
A light source control unit controls the first light emitting element and the second light emitting element to generate broadband light including the first wavelength band light and the second wavelength band light; There line and a control for generating a narrow-band light including by driving the first light emitting element and the first wavelength band light of the second light emitting element, a driving current applied to the first light emitting element, A method of operating a light source device for an endoscope, which emits the first light and the second light with the same light emission intensity by controlling a drive current applied to the second light emitting element . The light source device for endoscopes according to any one of claims 1 to 6 ,
An endoscope having an imaging element that images an observation target and outputs an image signal;
A first observation image is generated based on the image signal obtained by the imaging device imaging the observation object illuminated by the wide band light, and the imaging device images the observation object illuminated by the narrow band light An image processing unit that generates a second observation image based on the image signal obtained by
An endoscope system comprising: The imaging device includes an imaging drive unit that causes the imaging device to perform an imaging operation every one frame period.
9. The light source control unit according to claim 8 , wherein the broad band light and the narrow band light are alternately generated by controlling the first light emitting element and the second light emitting element for each one frame period. Endoscope system.

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