JP2016202774A - Endoscope light source device and endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope light source device and an endoscope system capable of matching the color of a dye scattering region when an addition-type light source is used to the color of a dye scattering region when a wideband light source is used.SOLUTION: The addition-type light source comprises: a red light source emitting first red light LR1; a green light source emitting green light LG of which wavelength band exists in a side having wavelengths longer than the peak wavelength of the first red light; and a first dichroic mirror (DM). The first red light LR1 enters one face of the first DM; the green light LG enters the other face of the first DM. The first DM has a band restriction property which reflects the light with wavelength bands between a first threshold T1A and a second threshold T1B. The first threshold T1A exists between the peak wavelength of the first red light LR1 and the peak wavelength of the green light LG. The second threshold T1B exists in a side of which wavelengths are longer than the peak wavelength of first red light LR1. The first DM extracts second red light LR2 which is a wavelength component of which wavelength is longer than the second threshold T1B and guides it to the light path of the first red light LR1.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an endoscope light source device and an endoscope system having an addition type light source.

  In the medical field, diagnosis using an endoscope system including an endoscope light source device (hereinafter referred to as a light source device), an endoscope, and a processor device is widely performed. The illumination light generated by the light source device is applied to the observation target from the distal end portion of the endoscope via a light guide in the endoscope. An imaging device is built in the distal end portion of the endoscope, and return light from the observation target is received by the imaging device. The processor device performs image processing on an image signal obtained by the imaging element to generate an observation image.

  As a light source device, a device that emits white broadband light (white light) by a discharge-type light source such as a xenon lamp is widely used. In recent years, a semiconductor light source such as a light emitting diode (LED) is being used instead of a discharge light source.

  In this light source device using the semiconductor light source, an addition type light source (hereinafter referred to as an addition type light source) that generates white light by adding each light emitted from a red LED, a green LED, and a blue LED is known. Yes. In the addition method light source, a semiconductor light source such as a red LED (Light Emitting Diode), a green LED, or a blue LED is used. Addition of light from each light source is performed using a dichroic mirror (see, for example, Patent Document 1).

  Also, in an endoscope system, depending on the purpose of diagnosis, a pigment such as pioctanin or indigo carmine is sprayed on an observation target, and the observation target colored with the pigment is imaged by an image sensor. For example, by dispersing pioctanin on the large intestine as an observation target, the lesion is stained blue-purple and the surface pattern is clarified. The nature of the lesion (whether benign or malignant) can be determined from this pattern.

Japanese Patent No. 5654167

  When the broadband light source is used, the pioctanine scattering region is observed as bluish violet, but when the additive light source is used, the color changes and the color tone may shift to the blue side. This is because the red LED, which is the red light source of the addition method light source, has a narrow wavelength band, and the amount of light on the long wavelength side is less than the illumination light of the broadband light source. In particular, although octanonin has a certain reflectance in a short wavelength band of about 500 nm or less and a long wavelength band of about 650 nm or more, the illumination light of the addition method light source has almost no wavelength component in the long wavelength band. Since it is not included, redness is insufficient and the color changes.

  As described above, doctors who are accustomed to observation with an endoscope system having a conventional broadband light source have a colorant such as pioctanin when observing with an endoscope system having a light source device having an additive light source. There is a possibility that the color of the spray area is recognized as a bluish color than before.

  The present invention relates to an endoscope light source device and an endoscope system capable of matching the color of a pigment dispersion region when an addition method light source is used with the color of a pigment dispersion region when a broadband light source is used. The purpose is to provide.

  In order to achieve the above object, an endoscope light source device according to the present invention emits a red light source that emits first red light and green light having a wavelength band that is longer than the peak wavelength of the first red light. A green light source, a first threshold value between the peak wavelength of the first red light and the peak wavelength of the green light, an optical path of a wavelength component having a wavelength shorter than the first threshold value of the green light, and the first red light A first optical path integrating unit that integrates an optical path of a wavelength component having a wavelength longer than the first threshold; and a first wavelength component having a wavelength longer than the second threshold that is longer than the peak wavelength of the first red light from the green light. A second optical path integrating unit that extracts two red lights and guides them to an optical path integrated by the first optical path integrating unit.

  The first optical path integrating unit and the second optical path integrating unit may be configured by one dichroic mirror having a band limiting characteristic that reflects or transmits light in a wavelength band between the first threshold value and the second threshold value. preferable. The first red light is incident on one surface of the dichroic mirror and the green light is incident on the other surface.

  The second threshold value is preferably in the range of 640 nm to 670 nm.

  The light amount of the second red light is preferably larger than the light amount of the wavelength component having a wavelength longer than the second threshold value of the first red light.

  The red light source is preferably composed of a light emitting diode, and the green light source is preferably composed of an excitation light source that generates excitation light and a phosphor that emits light upon receiving the excitation light. The green light preferably has a wavelength component of 500 nm to 690 nm.

  A blue light source that emits blue light, a third threshold value between the peak wavelength of blue light and the peak wavelength of green light, an optical path of a wavelength component having a wavelength shorter than the third threshold value of blue light, It is preferable to include a third optical path integrating unit that integrates optical paths of wavelength components having wavelengths longer than three threshold values.

  A purple light source that emits purple light, a fourth threshold value between the peak wavelength of purple light and the peak wavelength of blue light, an optical path of a wavelength component having a wavelength shorter than the fourth threshold value of purple light, It is preferable to include a fourth optical path integration unit that integrates optical paths of wavelength components having wavelengths longer than four threshold values.

  An endoscope system according to the present invention includes the above-described endoscope light source device, an imaging element that images an observation target illuminated by illumination light emitted from the endoscope light source device, and outputs a color image signal. An observation image generation unit that performs image processing on the image signal to generate an observation image, and a light emission ratio setting unit that sets a ratio of the light emission intensity of the red light source and the green light source.

  The light emission ratio setting unit includes a color of an observation target obtained by illuminating with a broadband light having a continuous spectrum in a green light band including green light and a red light band including first red light and second red light. It is preferable to set the ratio of the emission intensity that makes the color difference from the color of the observation object obtained by illuminating with the illumination light from the endoscope light source device equal to or less than a certain value. In this case, the color difference represents the distance in the Lab space, and the light emission ratio setting unit preferably sets the ratio of the light emission intensity so that the distance is 6 or less.

  It is preferable to provide a pigment spraying unit that sprays pioctanin to the observation target.

  According to the present invention, it is possible to match the color of the pigment dispersion region when the additive light source is used with the color of the pigment dispersion region when the broadband light source is used.

It is an external view of an endoscope system. It is a block diagram which shows the function of an endoscope system. It is a figure which shows the spectral characteristic of a color filter. It is a figure which shows the structure of an addition system light source. It is a graph which shows each luminescence intensity spectrum of purple light, blue light, green light, and 1st red light. It is a figure which shows the structure of G-LED. It is a graph which shows the optical characteristic of a 1st dichroic mirror. It is a graph which shows the optical characteristic of a 2nd dichroic mirror. It is a graph which shows the optical characteristic of a 3rd dichroic mirror. It is a graph which shows the optical characteristic of an infrared cut filter. (A) is a figure which shows the emission intensity spectrum of illumination light, (B) is a figure which shows the spectral reflection spectrum of a pigment | dye, (C) is a figure which shows the emission intensity spectrum of the illumination light of a broadband light source. (A) is a graph which shows the relationship between the emitted light intensity of R-LED, and a color difference, (B) is a figure which shows the relationship between the emitted light intensity of R-LED, and the gain amount with respect to a red image signal. It is a figure which shows the modification of the arrangement | sequence order of a 1st-3rd dichroic mirror. It is a figure which shows the structure of the addition system light source of 2nd Embodiment. It is a graph which shows the optical characteristic of the 1st dichroic mirror of 2nd Embodiment. It is a graph which shows the optical characteristic of the 2nd dichroic mirror of 2nd Embodiment.

[First Embodiment]
In FIG. 1, an endoscope system 10 includes an endoscope 12, an endoscope light source device (hereinafter referred to as a light source device) 14, a processor device 16, a monitor 18, and a console 19. . The endoscope 12 is optically connected to the light source device 14 and electrically connected to the processor device 16 by the universal cord 25.

  The endoscope 12 includes an insertion portion 12a to be inserted into the subject, an operation portion 12b provided at the proximal end portion of the insertion portion 12a, a bending portion 12c provided at the distal end side of the insertion portion 12a, and a bending portion. And a tip portion 12d provided at the tip of the portion 12c. By operating the angle knob 12e of the operation portion 12b, the bending portion 12c is bent. With this bending operation, the tip 12d is directed in a desired direction. In addition to the angle knob 12e, the operation unit 12b is provided with a zoom operation unit 13 and the like.

  The processor device 16 is electrically connected to the monitor 18 and the console 19. The monitor 18 is a display unit that outputs and displays image information and the like. The console 19 functions as a user interface that receives input operations such as function settings. Note that an external recording unit (not shown) for recording image information or the like may be connected to the processor device 16.

  The endoscope 12 is provided with a forceps channel 20. The forceps channel 20 is inserted with a spray tube 22 for spraying the pigment onto the observation target. The spray tube 22 is inserted into the forceps channel 20 from a forceps inlet 20a provided in the operation unit 12b. At least the distal end 22a of the spray tube 22 is exposed from a forceps outlet 20b formed at the distal end portion 12d of the endoscope 12.

  A syringe 24 filled with a coloring agent such as pioctane or indigo carmine is connected to the proximal end side of the spray tube 22. A user such as a doctor can spray the pigment in the form of a mist toward the observation target from the tip 22 a of the spray tube 22 by operating the syringe 24. The “pigment spraying portion” of the present invention corresponds to a configuration including the spray tube 22 and the syringe 24.

  In FIG. 2, the light source device 14 includes an addition method light source 30, a light source controller 31, and a light emission ratio setting unit 32. The addition method light source 30 is driven by the light source control unit 31 to generate white illumination light. The light emitted from the addition method light source 30 is irradiated to the observation target in the subject through the light guide 33 and the illumination lens 35 inserted into the insertion portion 12a.

  The light guide 33 is incorporated in the endoscope 12 and the universal cord 25, and propagates the illumination light supplied from the addition method light source 30 to the distal end portion 12d of the endoscope 12. As the light guide 33, a multimode fiber can be used. As an example, a thin fiber cable having a core diameter of about 105 μm, a clad diameter of about 125 μm, and a diameter including a sheath (protective layer) of φ0.3 mm to 0.5 mm can be used.

  The distal end portion 12d of the endoscope 12 is provided with an illumination optical system 34a and an imaging optical system 34b. The illumination optical system 34 a has an illumination lens 35. The illumination light emitted from the light guide 33 is applied to the observation target via the illumination lens 35. The imaging optical system 34 b includes an objective lens 36, a zoom lens 37, and an imaging element 38. The return light from the observation target of the illumination light enters the image sensor 38 through the objective lens 36 and the zoom lens 37. An optical image to be observed is formed on the image sensor 38.

  The zoom lens 37 moves between the tele end and the wide end in accordance with the operation of the zoom operation unit 13. When magnification observation is not performed (during non-magnification observation), the zoom lens 37 is disposed at the wide end. When performing magnified observation, the zoom lens 37 moves from the wide end to the tele end in accordance with the operation of the zoom operation unit 13.

  The image sensor 38 is a simultaneous primary color sensor that captures a light image to be observed and outputs a color image signal. As the image sensor 38, a complementary metal-oxide semiconductor (CMOS) type image sensor is used.

  The imaging device 38 has a red (R) color filter having the first spectral transmission characteristic 38a, a green (G) color filter having the second spectral transmission characteristic 38b, and a blue having the third spectral transmission characteristic 38c shown in FIG. (B) a color filter. Each pixel of the image sensor 38 is provided with any one color filter. That is, the image sensor 38 includes an R pixel (red pixel) provided with an R color filter, a G pixel (green pixel) provided with a G color filter, and a B pixel (blue pixel) provided with a B color filter. And output an RGB format image signal. This image signal is one in which any one of RGB color signals is assigned to each pixel, and includes a red image signal, a green image signal, and a blue image signal. Note that the B pixel has sensitivity to purple (V) light in addition to blue light.

  The image sensor 38 includes a correlated double sampling circuit and an A / D (Analog to Digital) converter, and outputs each image signal as a digital signal.

  The processor device 16 includes an imaging control unit 40, a reception unit 41, a DSP (Digital Signal Processor) 42, a noise reduction unit 43, an observation image generation unit 44, and a video signal generation unit 45. The imaging control unit 40 controls the imaging timing of the observation target by the imaging element 38 and the output timing of the image signal from the imaging element 38.

  The receiving unit 41 receives a digital RGB image signal output from the imaging device 38 of the endoscope 12. The DSP 42 performs various signal processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, and demosaicing processing on the received RGB image signal.

  In the defect correction process, the signal of the defective pixel of the image sensor 38 is corrected. In the offset process, the dark current component is removed from the RGB image signal subjected to the defect correction process, and an accurate zero level is set. In the gain correction process, the signal level is adjusted by multiplying the RGB image signal after the offset process by a specific gain value. The RGB image signal after the gain correction process is subjected to a linear matrix process for improving color reproducibility. After that, brightness and saturation are adjusted by gamma conversion processing. The RGB image signal after the linear matrix processing is subjected to demosaic processing (also referred to as isotropic processing or synchronization processing), and signals of RGB colors are generated for each pixel.

  The noise reduction unit 43 reduces noise by performing noise reduction processing (processing by a moving average method, a median filter method, or the like) on the RGB image signal subjected to demosaic processing or the like by the DSP 42. The RGB image signal with reduced noise is input to the observation image generation unit 44.

  The observation image generation unit 44 generates an observation image by performing image processing such as color conversion processing, color enhancement processing, and structure enhancement processing on the RGB image signal input from the noise reduction unit 43. In color conversion processing, color conversion processing is performed on RGB image signals by 3 × 3 matrix processing, gradation conversion processing, three-dimensional LUT (look-up table) processing, and the like. The color enhancement process is performed on the RGB image signal that has been subjected to the color conversion process. The structure enhancement process is a process for enhancing the structure of the observation target such as a surface blood vessel or a pit pattern, and is performed on the RGB image signal after the color enhancement process.

  The observation image generated by the observation image generation unit 44 is input to the video signal generation unit 45. The video signal generation unit 45 converts the observation image into a video signal for display on the monitor 18. The monitor 18 displays an image based on the video signal input from the video signal generation unit 45.

  In FIG. 4, the addition method light source 30 includes an R-LED 50a, a G-LED 50b, a B-LED 50c, a V-LED 50d, an LED driving unit 51, first to fourth collimator lenses 52a to 52d, To third dichroic mirrors (DM) 55a to 55c, an infrared cut filter 56, and a condenser lens 59.

  The addition method light source 30 is an addition method light source that generates illumination light by adding light emitted from the light sources of the R-LED 50a, the G-LED 50b, the B-LED 50c, and the V-LED 50d. In the present embodiment, the addition of light from the light source is performed by the first to third DMs 55a to 55c.

  As shown in FIG. 5, the R-LED 50a is a red light source that emits red light (hereinafter referred to as first red light LR1) having a peak wavelength of about 630 nm and a wavelength band of about 600 nm to 650 nm. The G-LED 50b is a green light source that emits green light LG having a peak wavelength of about 530 nm and a wavelength band of about 480 nm to 700 nm. The B-LED 50c is a blue light source that emits blue light LB having a peak wavelength of about 460 nm and a wavelength band of about 420 nm to 480 nm. The V-LED 50d is a violet light source that emits violet light LV having a peak wavelength of about 405 nm and a wavelength band of about 380 nm to 420 nm.

  Among the R-LED 50a, G-LED 50b, B-LED 50c, and V-LED 50d, the G-LED 50b is configured by a combination of an excitation LED 61 as an excitation light source and a green phosphor 62 as shown in FIG. ing. The excitation LED 61 generates excitation light LE having a peak wavelength of about 440 nm and makes it incident on the green phosphor 62. The green phosphor 62 emits light upon receiving the excitation light LE, and generates green light LG. Thus, since the G-LED 50b includes the green phosphor 62, the wavelength band of the green light LG extends from the green region to the longer wavelength side than the peak wavelength of the first red light LR1. The green light LG preferably has a wavelength component of at least 500 nm to 690 nm.

  The LED driving unit 51 drives the R-LED 50a, the G-LED 50b, the B-LED 50c, and the V-LED 50d, respectively.

  The first to fourth collimator lenses 52a to 52d are arranged so as to correspond to the R-LED 50a, the G-LED 50b, the B-LED 50c, and the V-LED 50d, respectively, and the first red light LR1, the green light LG, and the blue light. LB and violet light LV are parallelized. Hereinafter, the optical paths of the first red light LR1, the green light LG, the blue light LB, and the purple light LV collimated by the first to fourth collimator lenses 52a to 52d are respectively referred to as first to fourth optical paths 57a to 57d. Called.

  The first optical path 57a and the second optical path 57b are orthogonal to each other, and the first DM 55a is disposed at this intersection. Specifically, the first DM 55a is arranged such that one surface intersects the first optical path 57a at an angle of 45 ° and the other surface intersects the second optical path 57b at an angle of 45 °. As shown in FIG. 7, the first DM 55a has a first threshold T1A at about 590 nm and a second threshold T1B at about 650 nm. The first DM 55a transmits light having a wavelength shorter than the first threshold T1A, and reflects light having a wavelength longer than the first threshold T1A and shorter than the second threshold T1B. The first DM 55a transmits light having a wavelength longer than the second threshold value T1B. The first DM 55a has a band limiting characteristic that reflects light in a wavelength band between the first threshold T1A and the second threshold T1B.

  Since most of the wavelength component of the first red light LR1 emitted from the R-LED 50a is present in the wavelength band between the first threshold T1A and the second threshold T1B of the first DM 55a, it is reflected by the first DM 55a. . On the other hand, the green light LG emitted from the G-LED 50b has a wide wavelength band, and extends from the green light band to the longer wavelength side than the peak wavelength (about 630 nm) of the first red light LR1, so the first threshold T1A. A shorter wavelength component is transmitted through the first DM 55a, and a wavelength component longer than the second threshold value T1B is transmitted through the first DM 55a. Hereinafter, a wavelength component longer than the second threshold value T1B in the green light LG is referred to as a second red light LR2.

  As described above, the first DM 55a has an optical path having a wavelength component shorter than the first threshold T1A of the green light LG, an optical path having a wavelength component longer than the first threshold T1A of the first red light LR1, and the green light LG. The optical path of the wavelength component (second red light LR2) having a wavelength longer than the second threshold value T1B is integrated.

  In the present embodiment, the first DM 55a functions as the “first optical path integration unit” and the “second optical path integration unit” of the present invention. The first optical path integrating unit integrates an optical path having a wavelength component shorter than the first threshold T1A of the green light LG and an optical path having a wavelength component longer than the first threshold T1A of the first red light LR1. This integrated optical path is referred to as a first integrated optical path 58a. The second optical path integrating unit extracts the second red light LR2, which is a wavelength component having a wavelength longer than the second threshold T1B, from the green light LG, and guides it to the first integrated optical path 58a.

  The first threshold value T1A and the second threshold value T1B are wavelengths at which the light transmittance and light reflectance of the first DM 55a are approximately 50%. The first threshold value T1A exists between the peak wavelength of the first red light LR1 and the peak wavelength of the green light LG. The second threshold T1B is preferably longer than the peak wavelength of the first red light LR1 and exists in the range of 640 nm to 670 nm.

  The third optical path 57c and the fourth optical path 57d are orthogonal to each other, and the second DM 55b is disposed at this intersection. Specifically, the second DM 55b is arranged so that one surface intersects the third optical path 57c at an angle of 45 ° and the other surface intersects the fourth optical path 57d at an angle of 45 °. As shown in FIG. 8, the second DM 55b has a threshold T2 at about 425 nm, reflects light having a wavelength shorter than the threshold T2, and transmits light having a wavelength longer than the threshold T2. Here, the threshold value T2 is a wavelength at which the light transmittance and light reflectance of the second DM 55b are approximately 50%.

  By having this optical characteristic, the second DM 55b reflects most of the purple light LV and transmits most of the blue light LB. Therefore, the third optical path 57c and the fourth optical path 57d are integrated by the second DM 55b. Hereinafter, the optical path in which the third optical path 57c and the fourth optical path 57d are integrated is referred to as a second integrated optical path 58b.

  The first integrated optical path 58a and the second integrated optical path 58b are orthogonal to each other, and the third DM 55c is disposed at this intersection. Specifically, the third DM 55c is arranged such that one surface intersects the first integrated optical path 58a at an angle of 45 ° and the other surface intersects the second integrated optical path 58b at an angle of 45 °. As shown in FIG. 9, the third DM 55c has a threshold T3 at about 480 nm, reflects light having a wavelength shorter than the threshold T3, and transmits light having a wavelength longer than the threshold T3. Here, the threshold T3 is a wavelength at which the light transmittance and light reflectance of the third DM 55c are approximately 50%.

  By having this optical characteristic, the third DM 55c transmits most of the green light LG, the first red light LR1, and the second red light LR2 incident from the first integrated optical path 58a, and is incident from the second integrated optical path 58b. Most of the purple light LV and the blue light LB are reflected. Therefore, the first integrated optical path 58a and the second integrated optical path 58b are integrated by the third DM 55c. Hereinafter, the optical path in which the first integrated optical path 58a and the second integrated optical path 58b are integrated is referred to as a third integrated optical path 58c.

  In the present embodiment, the third DM 55c corresponds to the “third optical path integration unit” of the present invention, and the threshold T3 corresponds to the “third threshold”. The second DM 55b corresponds to the “fourth optical path integration unit” of the present invention, and the threshold T2 corresponds to the “fourth threshold”.

  The infrared cut filter 56 is disposed on the third integrated optical path 58c. As shown in FIG. 10, the infrared cut filter 56 has a threshold T4 of about 670 nm, transmits light having a wavelength shorter than the threshold T4, and reflects light having a wavelength longer than the threshold T4, thereby being longer than the threshold T4. Cuts light of wavelength (infrared). Here, the threshold value T4 is a wavelength at which the light transmittance and light reflectance of the infrared cut filter 56 are approximately 50%.

  The condensing lens 59 is disposed in the vicinity of the incident end of the light guide 33, condenses the light transmitted through the infrared cut filter 56, and makes it incident on the incident end of the light guide 33 as illumination light. This illumination light is emitted from the distal end portion 12d of the endoscope 12 and illuminates the observation target.

  The LED driving unit 51 is controlled by the light source control unit 31. The light emission ratio setting unit 32 stores a light emission intensity ratio setting value for each of the LEDs 50a to 50d. The light source control unit 31 adjusts the light emission intensity of each of the LEDs 50 a to 50 d by driving the LED driving unit 51 based on the set value of the light emission intensity ratio stored in the light emission ratio setting unit 32.

  Since the second red light LR2 is a partial component of the green light LG emitted from the G-LED 50b, the light amount of the second red light LR2 depends on the emission intensity of the G-LED 50b. The light emission intensity of the G-LED 50b is set so that the light amount of the second red light LR2 is larger than the light amount of the wavelength component having a longer wavelength than the second threshold value T1B (about 650 nm) of the first red light LR1. Yes.

  The set value stored in the light emission ratio setting unit 32 is set based on the color on the observation image of the observation target in which the picotanine is dispersed. Specifically, in the light emission ratio setting unit 32, when pioctanin is scattered on the observation target, the color of the pigment scattering area illuminated by the illumination light generated by the addition method light source 30, and the conventional broadband light source The setting value which makes the color difference with the color of the pigment | dye distribution area | region illuminated with the illumination light (broadband light) produced | generated by (1) below below a fixed value is memorize | stored. This color difference is represented by a distance ΔE in the Lab space. For example, a setting value that satisfies ΔE ≦ 6 is determined. The broadband light generated by the conventional broadband light source has a continuous emission intensity spectrum in at least a green light band including the green light LG and a red light band including the first red light LR1 and the second red light LR2. is there.

  The illumination light generated by the addition method light source 30 has a light emission intensity spectrum as shown in FIG. FIG. 11B shows a spectral reflection spectrum RS1 of pioctane and a spectral reflection spectrum RS2 of indigo carmine. Pioctanin has a certain reflectance in a wavelength band of about 470 nm or less and a wavelength band of about 640 nm or more. Indigo carmine has a certain reflectance in a wavelength band of about 520 nm or less and a wavelength band of about 670 nm or more.

  FIG. 11C shows an emission intensity spectrum of illumination light generated by a xenon light source, for example, as broadband light generated by a conventional broadband light source. This illumination light has a continuous emission intensity spectrum from about 400 nm to about 670 nm.

  In the conventional addition-type light source, the upper limit wavelength of the wavelength spectrum is about 650 nm. Therefore, the return light from the diffusing region of pioctane in the observation target hardly contains a red component having a wavelength longer than about 650 nm. The region is displayed in the observation image as a color close to blue. On the other hand, in the addition method light source 30 of the present embodiment, the wavelength component having a wavelength longer than the second threshold value T1B in the green light LG emitted from the G-LED 50c is extracted as the second red light LR2, and the illumination light is emitted. Therefore, the return light from the dispersion region of pioctane in the observation target contains a lot of red components on the longer wavelength side than about 650 nm. As a result, the scattering region is displayed in the observation image as a bluish violet color as in the case of using illumination light of a conventional broadband light source (see FIG. 11C).

  On the other hand, indigo carmine has a reflectance of a certain level or more in a wavelength band of about 670 nm or more. If the illumination light contains a lot of wavelength components of about 670 nm or more, indigo carmine contains The color will be reddish and displayed in the observation image. In the present embodiment, since the wavelength component of about 670 nm or more is cut from the illumination light by the infrared cut filter 56, indigo carmine uses the illumination light of a conventional broadband light source (see FIG. 11C). Similarly to the above, it is displayed in the observation image as blue.

  Next, the operation of the endoscope system 10 of the present embodiment will be described. First, a user such as a doctor conducts a distant view observation in the subject and performs screening in a state where the insertion portion 12a of the endoscope 12 is inserted into the subject such as the large intestine. At this time, a light emission operation of the light source device 14, an imaging operation by the imaging device 38 in the endoscope 12, an observation image generation operation by the processor device 16, and an image display operation of the observation image on the monitor 18 are performed.

  In the light source device 14, the light source control unit 31 controls the light emission intensity of each LED 50 a to 50 d of the addition method light source 30 by driving the LED drive unit 51 based on the setting value stored in the light emission ratio setting unit 32. . The lights (purple light LV, blue light LB, green light LG, first red light LR1) emitted from the LEDs 50a to 50d are combined by the first to third DMs 55a to 55c. Note that the first DM 55a has the optical characteristics shown in FIG. 7, and thus extracts the second red light LR2, which is a wavelength component having a wavelength longer than the second threshold T1B, from the green light LG, and thereby extracts the first threshold of the green light LG. The light is guided to an optical path having a wavelength component shorter than T1A.

  The light combined by the first to third DMs 55a to 55c passes through the infrared cut filter 56 to become illumination light having the emission intensity spectrum shown in FIG. The illumination light is collected by the condenser lens 59 and enters the light guide 33 in the endoscope 12, and is emitted from the distal end portion 12 d of the endoscope 12 to illuminate the observation target.

  The observation object illuminated by the illumination light is imaged by the image sensor 38 in the endoscope 12. The image sensor 38 generates digital RGB image signals and inputs them to the processor device 16. In the processor device 16, the RGB image signal is subjected to various signal processing by the DSP 42, subjected to noise reduction processing by the noise reduction unit 43, and input to the observation image generation unit 44. The observation image generation unit 44 generates an observation image by performing various image processing on the input RGB image signal. The observation image is displayed on the monitor 18 via the video signal generation unit 45. This observation image is displayed in red. This is because hemoglobin in the observation target absorbs shortwave light.

  When the user detects a possible lesion (such as a possible lesion) such as a brownish area or redness during screening, the user operates the zoom operation unit 13 to enlarge the observation target including the likely lesion. Perform magnified observation. In addition, the user disperses the pigment on the observation target in order to clarify the possible lesion site. Specifically, in the enlarged observation image, the user confirms the tip 22a of the spray tube 22 and then operates the syringe 24 filled with a coloring agent such as pioctane or indigo carmine to thereby obtain the coloring matter. Is sprayed on the observation target.

  The light emission operation, the imaging operation, the observation image generation operation, and the image display operation in this magnified observation are the same as in the distant view observation. On the monitor 18, an observation image including a lesion portion stained with the dispersed pigment is displayed. In the present embodiment, as described above, since the illumination light includes a wavelength component of about 650 nm to 670 nm, the pioctanin and indigo carmine in the observation target are the same as when using the illumination light of the conventional broadband light source, respectively. It is displayed on the observation image as a color.

  Thus, the color (color difference) of the color of the pigment distribution region observed by the endoscope system 10 of the present embodiment is different from the color of the pigment distribution region observed by an endoscope system having a conventional broadband light source. Even users who are small and accustomed to observation with an endoscope system having a conventional broadband light source do not feel a change in color.

  The light quantity of the second red light LR2 is about several percent of the total light quantity of the green light LG emitted from the G-LED 50c, and is smaller than the light quantity of the first red light LR1, so the light emission of the R-LED 50a. By reducing the intensity, the light quantity of the first red light LR1 is reduced, and at least in the wavelength component having a wavelength longer than the second threshold value T1B (about 650 nm), the light quantity of the second red light LR2 is the light quantity of the first red light LR1. It is preferable to make it larger. As a result, it is preferable to reduce the difference between the light amount of the first red light LR1 and the light amount of the second red light LR2. In this case, since the total red light amount of the first red light LR1 and the second red light LR2 decreases due to the decrease in the light amount of the first red light LR1, the DSP 42 performs gain correction on the red image signal. Preferably it is done. The DSP 42 corresponds to the “gain correction unit” of the present invention.

  As shown in FIG. 12A, the color difference decreases the light emission intensity of the R-LED 50a and decreases as the light amount of the first red light LR1 decreases. However, if the light amount of the first red light LR1 is reduced too much, the S / N of the red image signal is reduced, so that the light emission intensity of the R-LED 50a is such that the color difference becomes a predetermined value α (for example, ΔE = 6). Is preferably set. This set value of the emission intensity is referred to as β. The set value β is stored in the light emission ratio setting unit 32 together with the set values of the light emission intensities of the G-LED 50b, the B-LED 50c, and the V-LED 50d.

  The gain amount for the red image signal is set based on the set value β as shown in FIG. A gain amount corresponding to the set value β is γ. The gain amount γ increases as the emission intensity of the R-LED 50a decreases. The DSP 42 performs gain correction of the red image signal using the gain amount γ corresponding to the set value β stored in the light emission ratio setting unit 32.

  Note that the difference between the light amount of the first red light LR1 and the light amount of the second red light LR2 can be reduced by increasing the light emission intensity of the G-LED 50b instead of lowering the light emission intensity of the R-LED 50a. It is. That is, the light emission ratio setting unit 32 sets the light intensity ratio between the first red light LR1 and the second red light LR2 by setting the ratio of the light emission intensity between the R-LED 50a and the G-LED 50b.

  In the first embodiment, the optical characteristics shown in FIGS. 7 to 9 are used as the optical characteristics of the first to third DMs 55a to 55c. However, the present invention is not limited to this, and the relationship between transmission and reflection of each optical characteristic. It is also possible to reverse. For example, in the first embodiment, the first DM 55a has a band limiting characteristic that reflects light in the wavelength band between the first threshold T1A and the second threshold T1B. It is also possible to have a band limiting characteristic that transmits light in a wavelength band between the threshold T1B.

  Moreover, in the said 1st Embodiment, although 1st-3rd DM55a-55c is arrange | positioned as shown in FIG. 4, it is also possible to arrange | position in the order shown in FIG. In this case, the first DM 55a combines the violet light LV, the blue light LB, and the green light LG combined by the third DM 55c with the first red light LR1 emitted from the first DM 55a, and from the green light LG to green. The second red light LR2, which is a wavelength component having a wavelength longer than the second threshold value T1B, is extracted from the light LG and combined.

[Second Embodiment]
In the first embodiment, the second red light LR2 is extracted by providing the first DM 55a with a band limiting characteristic that reflects the wavelength band between the first threshold T1A and the second threshold T1B. Instead of the first DM 55a, the second red light LR2 can be extracted by providing a dichroic mirror having the first threshold value T1A and a dichroic mirror having the second threshold value T1B.

  In FIG. 14, the addition method light source 70 of the second embodiment is provided with first to fourth DMs 71 a to 71 d instead of the first to third DMs 55 a to 55 c of the addition method light source 30 of the first embodiment. Second mirrors 72a and 72b and a shielding plate 73 are provided. The same code | symbol is attached | subjected about the structure same as 1st Embodiment.

  The first DM 71a is arranged such that one surface intersects the first optical path 57a at an angle of 45 ° and the other surface intersects the second optical path 57b at an angle of 45 °. As shown in FIG. 15, the first DM 55a has a first threshold T1A at about 590 nm, transmits light having a wavelength shorter than the first threshold T1A, and reflects light having a wavelength longer than the first threshold T1A. Therefore, the first DM 71a integrates the optical path of the wavelength component having a wavelength shorter than the first threshold T1A of the green light LG and the optical path of the wavelength component having a wavelength longer than the first threshold T1A of the first red light LR1. This integrated optical path is referred to as a first integrated optical path 74a.

  On the other hand, a wavelength component (including the second red light LR2) having a wavelength longer than the first threshold value T1A of the green light LG is reflected by the first DM 71a and propagates through a branched optical path 74b orthogonal to the first integrated optical path 74a. First and second mirrors 72a and 72b are disposed on the branched light path 74b. The branched optical path 74b is bent by the first and second mirrors 72a and 72b and guided to the second DM 71b.

  The first integrated optical path 74a and the branched optical path 74b are orthogonal to each other, and the second DM 71b is disposed at this intersection. Specifically, the second DM 71b is arranged so that one surface intersects the first integrated optical path 74a at an angle of 45 ° and the other surface intersects the branched optical path 74b at an angle of 45 °. As shown in FIG. 16, the second DM 71b has a second threshold T1B at about 650 nm, transmits light having a wavelength shorter than the second threshold T1B, and reflects light having a wavelength longer than the second threshold T1B. Therefore, the second red light LR2 is extracted by the second DM 71b and guided to the first integrated optical path 74a.

  Thus, in the present embodiment, the first DM 71a corresponds to the “first optical path integration unit”, and the second DM 71b corresponds to the “second optical path integration unit”.

  The third DM 71c has the same configuration as the second DM 55b of the first embodiment, and integrates the third optical path 57c and the fourth optical path 57d. This integrated optical path is referred to as a second integrated optical path 64c. The first integrated optical path 74a and the second integrated optical path 74c are orthogonal to each other, and the fourth DM 71d is disposed at this intersection. The fourth DM 71d has the same configuration as the third DM 55c of the first embodiment, and integrates the first integrated optical path 74a and the second integrated optical path 74c. This integrated optical path is referred to as a third integrated optical path 74d.

  In the present embodiment, the fourth DM 71d corresponds to the “third optical path integrating unit” of the present invention, and the third DM 71c corresponds to the “fourth optical path integrating unit” of the present invention.

  As in the first embodiment, an infrared cut filter 56 and a condensing lens 59 are disposed in the third integrated optical path 74d, and the light that has passed through the infrared cut filter 56 and has been collected by the condensing lens 59 is provided. The light enters the light guide 33 as illumination light. The emission intensity spectrum of the illumination light is the same as that of the first embodiment, and is, for example, an emission intensity spectrum as shown in FIG.

  The shielding plate 73 is configured to be detachable on the branch optical path 74b, and moves between an insertion position where the shield plate 73 is inserted on the branch optical path 74b and a separation position where the shield plate 73 is detached from the branch optical path 74b. The movement of the shielding plate 73 is controlled by the light source control unit 31. When the shielding plate 73 is set to the insertion position, the second red light LR2 is shielded by the shielding plate 73 and is not guided to the first integrated optical path 74a. Thus, in the addition method light source 70 of the second embodiment, it is possible to select whether or not to add the second red light LR2 to the illumination light by controlling insertion / removal of the shielding plate 73.

  In place of the shielding plate 73, a shutter device such as a liquid crystal shutter that can control the light transmittance electrically is fixedly arranged on the branch light path 74b, and the light transmittance of the shutter device is controlled. Also good.

  Moreover, in the said 1st and 2nd embodiment, although V-LED50d as a purple light source is provided in the addition system light sources 30 and 70, this purple light source is not essential. Therefore, an addition method light source may be configured by a blue light source, a green light source, and a red light source without providing a purple light source. Furthermore, it is also possible to use blue excitation light LE emitted from an excitation light source included in the G-LED 50c as a blue component of illumination light without providing a blue light source. Therefore, it is also possible to configure an addition type light source with a green light source and a red light source.

  Moreover, in the said 1st and 2nd embodiment, although the infrared cut filter 56 is provided, the illumination light produced | generated by the addition system light sources 30 and 70 is compared with the illumination light produced | generated by the conventional broadband light source, Since the wavelength component on the long wavelength side is smaller than the threshold value T4 of about 670 nm, the infrared cut filter 56 is not essential and may be provided as necessary.

  In the first and second embodiments, a primary color sensor is used as the image sensor 38, but a complementary color sensor may be used instead. This complementary color sensor preferably has a cyan (C) pixel, a magenta (Mg) pixel, a yellow (Y) pixel, and a green (G) pixel. As described above, when the image sensor 38 is a complementary color sensor, the processor device 16 may perform an operation for converting a complementary color image signal (CMYG image signal) into a primary color image signal (RGB image signal).

  In the first and second embodiments, a CMOS type image sensor is used as the image sensor 38, but a CCD (Charge-Coupled Device) type image sensor may be used instead.

  In the first and second embodiments, a xenon light source, which is a kind of high-intensity discharge light source, is used as a conventional broadband light source to be compared with the addition method light source of the present invention. Other broadband light sources may be used as long as they have a continuous emission intensity spectrum including the wavelength bands of the first red light LR1 and the second red light LR2. For example, you may use the broadband light source described in Unexamined-Japanese-Patent No. 2014-121630. This broadband light source has a laser light source that emits blue laser light having a center wavelength of about 445 nm, and a phosphor that emits white fluorescence in response to the blue laser light.

  In the first and second embodiments, the light source device and the processor device are configured separately, but the light source device and the processor device may be configured as a single device.

DESCRIPTION OF SYMBOLS 10 Endoscope system 12 Endoscope 14 Light source apparatus 16 Processor apparatus 20 Forceps channel 22 Dispersion tube 22a Tip 24 Syringe 30,70 Addition system light source 55a-55c First to third dichroic mirror 56 Infrared cut filter 71a-71d 1st ~ 4th dichroic mirror 73 Shield plate

Claims (13)

A red light source emitting a first red light;
A green light source that emits green light having a wavelength band that is longer than the peak wavelength of the first red light;
A first threshold value between a peak wavelength of the first red light and a peak wavelength of the green light, an optical path of a wavelength component having a wavelength shorter than the first threshold value of the green light, and the first red light A first optical path integrating unit that integrates an optical path of a wavelength component having a wavelength longer than the first threshold;
Extracting from the green light the second red light that is a wavelength component having a wavelength longer than the second threshold that is longer than the peak wavelength of the first red light, and integrating the second red light into the optical path integrated by the first optical path integrating unit A second optical path integration unit for guiding;
An endoscope light source device comprising:   The first optical path integration unit and the second optical path integration unit are configured by one dichroic mirror having a band limiting characteristic that reflects or transmits light in a wavelength band between the first threshold value and the second threshold value. The endoscope light source device according to claim 1.   The endoscope light source device according to claim 2, wherein the first red light is incident on one surface of the dichroic mirror and the green light is incident on the other surface.   The endoscope light source device according to any one of claims 1 to 3, wherein the second threshold value is in a range of 640 nm to 670 nm.   5. The endoscope light source device according to claim 1, wherein a light amount of the second red light is larger than a light amount of a wavelength component having a wavelength longer than the second threshold value of the first red light. The red light source is composed of a light emitting diode,
6. The endoscope light source device according to claim 5, wherein the green light source includes an excitation light source that generates excitation light and a phosphor that emits light upon receiving the excitation light.   The endoscope light source device according to claim 6, wherein the green light has a wavelength component of 500 nm to 690 nm. A blue light source emitting blue light;
A third threshold between the peak wavelength of the blue light and the peak wavelength of the green light, an optical path of a wavelength component having a wavelength shorter than the third threshold of the blue light, and the third threshold of the green light A third optical path integrating unit that integrates optical paths of longer wavelength components;
An endoscope light source device according to any one of claims 1 to 7. A purple light source that emits purple light;
A fourth threshold value between the peak wavelength of the violet light and the peak wavelength of the blue light; an optical path of a wavelength component having a wavelength shorter than the fourth threshold value of the violet light; and the fourth threshold value of the blue light. A fourth optical path integrating unit that integrates optical paths of longer wavelength components;
An endoscope light source device according to claim 8. An endoscope light source device according to claim 1;
An imaging element that images an observation object illuminated by illumination light emitted by the endoscope light source device and outputs a color image signal;
An observation image generation unit that performs image processing on the image signal to generate an observation image;
A light emission ratio setting unit for setting a light emission intensity ratio between the red light source and the green light source;
An endoscope system comprising:   The emission ratio setting unit is an observation obtained by illuminating with broadband light having a continuous spectrum in the green light band including the green light and the red light band including the first red light and the second red light. The ratio of the emission intensity that sets the color difference between the target color and the color of the observation target obtained by illuminating with the illumination light from the endoscope light source device to a certain value or less is set. The endoscope system described. The color difference represents a distance in Lab space,
The endoscope system according to claim 11, wherein the light emission ratio setting unit sets a ratio of the light emission intensity so that the distance is 6 or less.   The endoscope system according to claim 11 or 12, further comprising a pigment spraying unit that sprays pioctanin to the observation target.

Images