JP6905038B2 - Light source device and endoscopic system - Google Patents

Description

The present invention relates to a light source device and an endoscope system that generate illumination light that illuminates an observation object by using light emitted by a plurality of light sources.

In the medical field, it is common to make a diagnosis using an endoscope system including a light source device, an endoscope, and a processor device. The light source device produces, for example, white light as illumination light. The endoscope photographs the observation target illuminated by the illumination light. Then, the processor device generates an observation image (hereinafter, referred to as an observation image) used for diagnosis by using an observation target image (hereinafter, referred to as a captured image) taken by the endoscope, and displays it on a monitor.

As the light source device used in the endoscope system, for example, as in Patent Document 1, white illumination light emitted by a lamp such as a xenon lamp is used, but in recent years, a semiconductor light source such as an LED (Light Emitting Diode) has been used. There is known a light source device that emits white illumination light using a light source device (Patent Document 2). Further, as in Patent Document 1 and Patent Document 2, in the light source device of the endoscope system, an optical filter may be used to adjust the light component contained in the illumination light.

Japanese Unexamined Patent Publication No. 2004-121486 Japanese Unexamined Patent Publication No. 2016-007355

When the illumination light is emitted by using a semiconductor light source such as an LED, it is required to be able to observe the observation target as in the case of using a conventional light source device which emits the illumination light by using a lamp. However, if an observation image taken with the illumination light emitted by the conventional lamp is to be reproduced by using the illumination light emitted by a monochromatic light source such as an LED, it is necessary to use light sources of a plurality of colors. That is, it is necessary to prepare light sources of at least three primary colors. For example, when an LED is used as a light source for illumination light, the light source device needs to be equipped with blue, green, and red LEDs. Then, in order to further improve the reproducibility of the observed image, or to realize other special observation modes, it is necessary to add a light source of another color in addition to these.

As described above, if the light source device is provided with light sources of various colors, it is possible to reproduce an observation image when a lamp is used and to realize a special observation mode. As the number is increased, there is a problem that the light source device becomes huge due to these arrangement spaces and the manufacturing cost also increases.

An object of the present invention is to provide a light source device that is more compact and cheaper than the conventional one, and an endoscope system that has a compact and cheap light source device.

The optical device of the present invention adjusts the amount of light of a first light source that emits blue light, a second light source that emits a wide band green light containing a red component in addition to a green component, and a wide band green light for each wavelength. The optical filter includes an optical filter, and the optical filter has a wide band green light transmittance when transmitting a wide band green light or a wide band green light reflectance when reflecting a wide band green light. In the range of, it increases smoothly toward the long wavelength side.

The second light source includes a light emitting element that emits excitation light and a phosphor that emits broadband green light when irradiated with the excitation light, and the optical filter preferably cuts the excitation light. It is preferable that the optical filter has a stepped change in reflectance or transmittance for each component except in the range of the red component. The optical filter preferably has a smooth change in reflectance or transmittance for each component.

The optical filter is preferably a wave combining member that combines blue light and broadband green light. In addition to the first light source and the second light source, it is preferable to provide an additional light source that emits light having a difference in the extinction coefficient between the oxidized hemoglobin and the reduced hemoglobin. In addition to the first light source and the second light source, it is preferable to provide an additional light source that emits infrared light. In addition to the optical filter, or interchangeable with the optical filter, it is preferable to include a second optical filter that dims the red component from the wideband green light. The light amount ratio R / G of the green component G and the red component R of the wide band green light after passing through the optical filter is the light amount ratio R / G of the green component G and the red component R of the wide band green light before passing through the optical filter. Is preferably larger than.

The endoscope system of the present invention has a first light source that emits blue light, a second light source that emits wideband green light containing a red component in addition to the green component, and a wide band green light amount for each wavelength. It has an optical filter that adjusts, and the optical filter has a wide band green light transmittance when transmitting a wide band green light, or a wide band green light reflectance when reflecting a wide band green light. It is provided with a light source device that smoothly increases toward a long wavelength side in the range of the red component, and an image sensor that captures an observation target using blue light and wideband green light whose components are adjusted by an optical filter.

The image sensor is preferably a color sensor having a color filter for each pixel. It is preferable that the gain applied to the red image obtained by photographing the observation target using the red component is larger than the gain applied to the green image obtained by photographing the observation object using the green component.

The light source device of the present invention has, as a light source, a first light source that emits blue light and a second light source that emits broadband green light containing a red component in addition to the green component, and uses an optical filter. By adjusting the amount of wideband green light for each wavelength, white illumination light is formed as a whole. Therefore, the light source device and the endoscope system of the present invention can omit the red light source that emits red light, and are therefore more compact and cheaper than the conventional ones.

It is a schematic diagram of an endoscope system. It is a block diagram of an endoscope system. It is a graph which shows the transmittance of a color filter. It is a block diagram of the light source part which a light source device has. It is a graph which shows the spectral spectrum of the wide band green light emitted by the 2nd light source. It is a graph which shows the characteristic of an optical filter. It is a graph which shows the spectral spectrum of the wide band green light which passed through an optical filter. It is a graph which shows the characteristic of the optical filter of the modification. It is a spectroscopic spectrum of illumination light. It is a block diagram of an endoscope system in which a light source device and a processor device are integrated. It is an array of conventional primary color filters. It is an array of primary color filters in which the sensitivity of the green component G is lowered and the sensitivity of the red component R is increased. This is an array of conventional complementary color filters. It is an array of complementary color filters in which the sensitivity of the green component G is lowered and the sensitivity of the red component R is increased. It is an array of complementary color filters with increased sensitivity of the red component R. It is an array of complementary color filters with increased sensitivity of the red component R. It is a block diagram of the light source apparatus provided with the additional light source. It is a graph which shows the extinction coefficient of oxidized hemoglobin and reduced hemoglobin. It is a block diagram of the light source part which provided the 2nd optical filter in addition to the optical filter. It is a graph which shows the characteristic of the 2nd optical filter. It is a block diagram of another light source part provided with a 2nd optical filter in addition to an optical filter. It is a block diagram of the light source part which provided the 2nd optical filter exchangeable with an optical filter. It is a graph which shows the characteristic of the 2nd optical filter provided interchangeably with an optical filter. It is a schematic diagram of a capsule endoscope. It is a spectral spectrum of white light emitted by a white LED. It is a spectral spectrum of white light emitted by another white LED.

[First Embodiment]
As shown in FIG. 1, the endoscope system 10 includes an endoscope 12 for photographing an observation target, a light source device 14, a processor device 16, a monitor 18 as a display unit, and a console 19. The endoscope 12 is optically connected to the light source device 14 and electrically connected to the processor device 16. The endoscope 12 includes an insertion portion 12a to be inserted into the subject, an operation portion 12b provided at the base end portion of the insertion portion 12a, a curved portion 12c provided on the tip end side of the insertion portion 12a, and a tip portion 12d. Has. By operating the angle knob 12e of the operation unit 12b, the curved portion 12c is curved. As a result of the curved portion 12c being curved, the tip portion 12d is oriented in a desired direction. The tip portion 12d is provided with an injection port (not shown) for injecting air, water, or the like toward the observation target. Further, the operation unit 12b is provided with a zoom operation unit 13a and a mode changeover switch 13b in addition to the angle knob 12e. The zoom operation unit 13a is used when the observation target is enlarged or reduced. The mode changeover switch 13b is used for switching the observation mode when the endoscope system 10 has a plurality of observation modes.

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

As shown in FIG. 2, the light source device 14 includes a light source unit 20 that emits illumination light, and a light source control unit 22 that controls the emission timing of the illumination light, the amount of the illumination light, the components of the illumination light, and the like. .. In the present embodiment, the illumination light is generally white light.

The illumination light emitted by the light source unit 20 is incident on the light guide 41. The light guide 41 is built in the endoscope 12 and the universal cord, and propagates the illumination light to the tip portion 12d of the endoscope 12. The universal cord is a cord that connects the endoscope 12, the light source device 14, and the processor device 16. A multimode fiber can be used as the light guide 41. As an example, a fine fiber cable having a core diameter of 105 μm, a clad diameter of 125 μm, and a diameter of φ0.3 to 0.5 mm including a protective layer serving as an outer skin can be used.

The tip portion 12d of the endoscope 12 is provided with an illumination optical system 30a and a photographing optical system 30b. The illumination optical system 30a has an illumination lens 45, and the illumination light is applied to the observation target through the illumination lens 45. The photographing optical system 30b includes an objective lens 46, a zoom lens 47, and an image sensor 48. The image sensor 48 uses the reflected light of the illumination light returning from the observation target via the objective lens 46 and the zoom lens 47 (in addition to the reflected light, scattered light, fluorescence emitted by the observation target, or a drug administered to the observation target). The observation target is photographed using (including fluorescence caused by). The zoom lens 47 moves by operating the zoom operation unit 13a. As a result, the observation target to be photographed by using the image sensor 48 is enlarged or reduced for observation.

In the present embodiment, the image sensor 48 is a so-called primary color sensor having a color filter for each pixel. Therefore, each pixel of the image sensor 48 has, for example, one of the R color filter (red color filter), the G color filter (green color filter), and the B color filter (blue color filter) shown in FIG. .. A pixel having an R color filter is an R pixel, a pixel having a G color filter is a G pixel, and a pixel having a B color filter is a B pixel. As described above, since the image sensor 48 has three color pixels of R pixel, G pixel, and B pixel, when the observation target is photographed by using white light as the illumination light, the observation target is photographed by the R pixel. The R image obtained by photographing the observation target with the G pixel, the G image obtained by photographing the observation target with the G pixel, and the B image obtained by photographing the observation object with the B pixel are simultaneously obtained.

As the image sensor 48, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor can be used. Further, although the image sensor 48 of the present embodiment is a primary color sensor, a complementary color sensor can also be used. Complementary color sensors include, for example, a cyan pixel provided with a cyan color filter, a magenta pixel provided with a magenta color filter, a yellow pixel provided with a yellow color filter, and a green pixel provided with a green color filter. Has. When using a complementary color sensor, the image obtained from the pixels of each of the above colors can be converted into a B image, a G image, and an R image by performing complementary color-primary color conversion. Further, instead of the color sensor, a monochrome sensor without a color filter can be used as the image sensor 48. In this case, an image of each of the above colors can be obtained by sequentially photographing the observation target using illumination light of each color such as BGR.

The processor device 16 includes an image acquisition unit 54, an image processing unit 61, a display control unit 66, and a control unit 69.

The image acquisition unit 54 acquires captured images of a plurality of colors obtained by photographing the observation target using the image sensor 48. Specifically, the image acquisition unit 54 acquires a set of a B image, a G image, and an R image for each shooting frame. Further, the image acquisition unit 54 includes a DSP (Digital Signal Processor) 56, a noise reduction unit 58, and a conversion unit 59, and uses these to perform various processes on the acquired image.

The DSP 56 performs various processes such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, demosaic processing, and YC conversion processing on the acquired image as necessary.

The defect correction process is a process for correcting the pixel value of the pixel corresponding to the defective pixel of the image sensor 48. The offset processing is a processing for reducing the dark current component from the image subjected to the defect correction processing and setting an accurate zero level. The gain correction process is a process of adjusting the signal level of each image by multiplying the offset processed image by the gain. The linear matrix processing is a process for improving the color reproducibility of the offset processed image, and the gamma conversion process is a process for adjusting the brightness and saturation of the image after the linear matrix processing. The demosaic process (also referred to as isotropic processing or simultaneous processing) is a process of interpolating the pixel values of the missing pixels, and is applied to the image after the gamma conversion process. The missing pixel is a pixel having no pixel value because pixels of other colors are arranged in the image sensor 48 due to the arrangement of the color filters. For example, since the B image is an image obtained by photographing the observation target in the B pixel, the pixel at the position corresponding to the G pixel and the R pixel of the image sensor 48 has no pixel value. The demosaic process interpolates the B image to generate pixel values of the pixels at the positions of the G pixel and the R pixel of the image sensor 48. The YC conversion process is a process of converting the image after the demosaic process into the luminance channel Y, the color difference channel Cb, and the color difference channel Cr.

The noise reduction unit 58 performs noise reduction processing on the luminance channel Y, the color difference channel Cb, and the color difference channel Cr by using, for example, a moving average method or a median filter method. The conversion unit 59 reconverts the luminance channel Y, the color difference channel Cb, and the color difference channel Cr after the noise reduction processing into images of each color of BGR.

The image processing unit 61 performs color conversion processing, color enhancement processing, and structure enhancement processing on the B image, G image, and R image for one shooting frame subjected to the above various processing to generate an observation image. .. The color conversion process performs 3 × 3 matrix processing, gradation conversion processing, three-dimensional LUT (look-up table) processing, and the like for images of each BGR color. The color enhancement process is a process for emphasizing the color of an image, and the structure enhancement process is a process for emphasizing a tissue or structure to be observed such as a blood vessel or a pit pattern.

The display control unit 66 sequentially acquires observation images from the image processing unit 61, converts the acquired observation images into a format suitable for display, and sequentially outputs and displays them on the monitor 18. As a result, a doctor or the like can observe the observation target using a still image or a moving image of the observation image.

The control unit 69 is, for example, a CPU (Central Processing Unit), and performs overall control of the endoscope system 10 such as synchronous control of emission timing of illumination light and a shooting frame. When the endoscope system 10 has a plurality of observation modes, the control unit 69 switches the illumination light via the light source control unit 22 by receiving an operation input from the mode changeover switch 13b. As a result, the observation mode is switched.

Hereinafter, the configuration and operation of the light source device 14 will be described in more detail. As shown in FIG. 4, the light source unit 20 of the light source device 14 includes a first light source 71, a second light source 72, and an optical filter 73. Further, in the present embodiment, the light source unit 20 includes an additional light source 74 in addition to the first light source 71 and the second light source 72. The first light source 71, the second light source 72, and the additional light source 74 can be controlled independently.

The first light source 71 emits light composed of the blue component B (hereinafter referred to as blue light). The first light source 71 includes a light emitting element 81 and a lens 82 that adjusts the blue light emitted by the light emitting element 81 into parallel light or the like. The light emitting element 81 is, for example, a semiconductor element such as an LED or an LD (Laser Diode). The blue light emitted by the first light source 71 is incident on the light guide 41 via the wave combining member 76 and the wave wave member 77 that transmit the blue light. The combiner member 76 and the combiner member 77 are, for example, a dichroic mirror or a dichroic prism.

In general, the wavelength of blue is about 445 nm to about 485 nm, and for example, a color intermediate between blue and green may be referred to as blue-green to distinguish it from blue. However, in the endoscope system 10, it is not necessary to excessively subdivide the color type (color name) of at least the light emitted by each light source of the light source unit 20. Therefore, in the present specification, the color of light having a wavelength of about 440 nm or more and less than about 490 nm is referred to as blue. Further, the color of light having a wavelength of about 490 nm or more and less than about 600 nm is referred to as green, and the color of light having a wavelength of about 600 nm or more and less than about 680 nm is referred to as red. The color of visible light having a wavelength less than "about 440 nm", which is the lower limit of the blue wavelength (for example, visible light of about 380 nm or more and less than about 440 nm) is called purple, which is shorter than purple but has an image sensor. When 48 represents the color of light having sensitivity, it is called ultraviolet. Further, when the image sensor 48 represents the color of light having a wavelength of "about 680 nm" or more, which is the upper limit of the wavelength of red, and the image sensor 48 has sensitivity, it is referred to as infrared. Further, in the present specification, "broadband" means that the wavelength range extends over the wavelength range of a plurality of colors. White refers to the color of light including at least the light belonging to the above blue or purple, the light belonging to green, and the light of the color belonging to red.

The second light source 72 emits a wide band of light including a red component R in addition to the green component G. However, the light emitted by the second light source 72 is generally green when visually recognized because the amount of light of the green component G is larger than the amount of light of the red component R. Therefore, in the present specification, the light emitted by the second light source 72 is referred to as green light. That is, the second light source 72 is a light source that emits a wide band of green light.

The second light source 72 includes a light emitting element 83 that emits excitation light Ex, a phosphor 84 that emits green light when the excitation light Ex emitted by the light emitting element 83 is incident, and a wide band green light emitted by the phosphor 84. It includes a lens 85 that adjusts the light to parallel light or the like. The light emitting element 83 is, for example, a semiconductor element such as an LED or an LD. Further, as shown in FIG. 5, the excitation light Ex is blue light having a peak at about 445 nm, and the green light emitted by the phosphor 84 is a wide-band green light containing a red component R in addition to the green component G. It is light. As described above, the wide band green light emitted by the second light source 72 is incident on the light guide 41 via the optical filter 73 and the combiner member 77 that reflects the green component G and the red component R.

The optical filter 73 has the spectral transmittance shown in FIG. Therefore, as shown in FIG. 7, the optical filter 73 adjusts the amount of wideband green light emitted by the second light source 72 for each wavelength. More specifically, the optical filter 73 adjusts the light amount ratio R / G of the green component G and the red component R of the wide band green light emitted by the second light source 72.

For example, in the present embodiment, the light amount ratio R / G of the green component G and the red component R of the wide band green light emitted by the second light source 72 is about 0.15. On the other hand, through the optical filter 73, the light intensity ratio R / G of the green component G and the red component R of the wide band green light becomes about 0.22 when incident on the light guide 41. Let "Gb" be the amount of green light of the wide band green light emitted by the second light source 72 (that is, before passing through the optical filter 73), and "Ga" be the amount of green light after passing through the optical filter 73. In this case, the light amount ratio Ga / Gb of the green component G before and after passing through the optical filter 73 is about 0.52. Further, when the amount of red component R of the broadband green light emitted by the second light source 72 is "Rb" and the amount of green light after passing through the optical filter 73 is "Ra", before and after passing through the optical filter 73. The light intensity ratio Ra / Rb of the red component R of the above is about 0.75.

As described above, the optical filter 73 adjusts the light amount ratio R / G of the green component G and the red component R of the wide band green light in order to make the illumination light white light suitable for photographing the observation target. .. The white light suitable for photographing an observation target is, for example, white light used as illumination light in a conventional endoscope system. The light source device 14 of the endoscope system 10 includes a first light source 71 that emits blue light and a second light source 72 that emits broadband green light, but does not provide a light source that emits red light. Therefore, even though the broadband green light contains the red component R, if the blue light and the wide band green light are simply combined to form the illumination light, the blue component B is included in the illumination light after the combined wave. And since the red component R is relatively insufficient with respect to the green component G, the illumination light becomes, for example, cyan (light blue). As a result, the color of the observed image becomes unnatural.

On the other hand, when the light amount ratio R / G of the green component G and the red component R of the wide band green light is adjusted as described above by using the optical filter 73, at least the green component G and the red component R contained in the illumination light are to be observed. The light intensity ratio is suitable for shooting. Since the amount of blue light of the first light source 71 and the amount of broadband green light of the second light source 72 can be controlled independently, the green component G and the red component of the wide band green light are controlled by using the optical filter 73. If the light amount ratio R / G of R is adjusted as described above and the light source control unit 22 appropriately adjusts the light emission amount of the first light source 71 and the second light source 72, the illumination light is suitable for photographing the observation target. It becomes white light.

The specific adjustment target value of the light amount ratio R / G is the spectral characteristics of the wide band green light emitted by the second light source 72, the spectral characteristics of the color filters of each color of the image sensor 48, and the image acquired from the image sensor 48. It is determined in consideration of the gain at the time of performing, the content of various processing performed by the DSP 56 (for example, the matrix used in the linear matrix processing), and the like. As a result, the optical filter 73 adjusts the ratio of the brightness of the G image and the R image. Therefore, when the light amount ratio of the green component G and the red component R of the wide band green light is adjusted by using the optical filter 73, the G image and the R image obtained when the observation target is photographed using the white light as the adjustment target The brightness ratio and the brightness ratio of the G image and the R image obtained when the observation target is photographed using the illumination light generated by the light source device 14 are substantially the same. That is, although the light source device 14 does not have a red light source that emits red light, the obtained observation image has the same color as the observation image obtained when the observation target is photographed using the white light as the adjustment target.

As described above, the light source unit 20 is not provided with a red light source that emits red light, but instead uses the red component R, which is a part of the wide band green light of the second light source 72 on the long wavelength side, to provide illumination light. Since the light is white, the amount of light of the green component G is excessive as compared with the red component R. Therefore, the spectral transmittance of the optical filter 73 (see FIG. 6) is such that at least the transmittance of the green component G is smaller than the transmittance of the red component R. In the present embodiment, the optical filter 73 transmits the wide band green light emitted by the second light source 72 and guides the light guide 41, but of course, the optical filter 73 reflects the wide band green light. The light guide 41 can be configured to guide light. In this case, the spectral reflectance of the optical filter 73 is the same as that of FIG. 6, for example, and at least the reflectance of the green component is smaller than the reflectance of the red component. That is, the optical filter 73 has a characteristic (spectral reflectance) in which at least the reflectance of the green component G is smaller than the reflectance of the red component R when the wide band green light is reflected and guided to the light guide 41. Or, when a wide band of green light is transmitted and guided to the light guide 41, the transmittance of at least the green component G is smaller than the transmittance of the red component R (spectral reflectance).

The optical filter 73 has a smooth change in transmittance for each wavelength. Specifically, in the range of the green component G, the transmittance for each wavelength is substantially constant, and in the range of the red component R, the transmittance for each wavelength smoothly and gradually increases toward the long wavelength side. This spectral transmittance takes into consideration the reproducibility (easiness of image) of the structure of blood vessels and the like. For example, in the endoscope system 10 and the conventional endoscope system, the depth and thickness of blood vessels that are easily captured change according to the wavelength of the light contained in the illumination light, so that the spectral spectrum of the illumination light (for each wavelength) changes. If the amount of light) is different, the imageability of blood vessels of a certain depth and thickness may differ. Therefore, the optical filter 73 smoothes the change in the reflectance for each wavelength and reproduces substantially the same spectral spectrum as the white light to be adjusted in the range of the green component G and the red component R. When the optical filter 73 is constructed more simply, the change in the transmittance for each wavelength can be stepped. For example, as shown in FIG. 8, the spectral transmittance of the optical filter 73 can be configured to have substantially constant transmittance in the wavelength range of the green component G and the wavelength range of the red component R, respectively. The same applies to the spectral reflectance of the optical filter 73 when the wide band green light is reflected and guided to the light guide 41.

As can be seen from the spectral transmittance (see FIG. 6), the optical filter 73 also functions as an excitation light cut filter that cuts the excitation light Ex. Therefore, a part of the excitation light Ex passes through the phosphor 84 and enters the optical filter 73, but does not enter the light guide 41 because the optical filter 73 cuts. In the present embodiment, the optical filter 73 and the combiner member 77 are provided separately, but the optical filter 73 can be integrated with the combiner member 77. In this case, the optical filter 73 adjusts the light amount ratio of the green component G and the red component R when reflecting the wide band green light and guiding the light to the light guide 41, and the blue light emitted by the first light source 71. It also functions as a combiner member that combines the above and the wide band green light emitted by the second light source 72.

The additional light source 74 emits light composed of the purple component V (hereinafter referred to as purple light). The additional light source 74 includes a light emitting element 86 and a lens 87 that adjusts the purple light emitted by the light emitting element 86 into parallel light or the like. The light emitting element 86 is, for example, a semiconductor element such as an LED or an LD. The violet light emitted by the additional light source 74 is incident on the light guide 41 via the conjugating member 76 that reflects the violet light and the merging member 77 that transmits the violet light. The purple component V of the purple light is received by the B pixel in the image sensor 48. Therefore, the reflected light of purple light and the like contribute to the B image together with the reflected light of blue light and the like.

The light source unit 20 includes the first light source 71, the second light source 72, the optical filter 73, the additional light source 74, the photodetectors 91, 92 and 93, the beam splitters 94, 95 and 96, and each of them. A cooling member (so-called heat sink, not shown) for cooling the light emitting element of the light source is provided. The beam splitter 94 reflects a part of the blue light emitted by the first light source 71 at a predetermined ratio, and the photodetector 91 receives the blue light reflected by the beam splitter 94. The beam splitter 95 reflects a part of the wide band green light emitted by the second light source 72 at a predetermined ratio, and the photodetector 92 receives the wide band green light reflected by the beam splitter 94. The beam splitter 96 reflects a part of the purple light emitted by the additional light source 74 at a predetermined ratio, and the photodetector 93 receives the purple light reflected by the beam splitter 96. The light source control unit 22 automatically and accurately controls the amount of blue light emitted from the first light source 71 using the amount of light detected by the photodetector 91. Further, the light source control unit 22 automatically and accurately controls the amount of light emitted from the wide band green light of the second light source 72 by using the amount of light detected by the photodetector 92. Similarly, the light source control unit 22 automatically and accurately controls the amount of violet light emitted by the additional light source 74 using the amount of light detected by the photodetector 93.

The light source device 14 configured as described above emits, for example, the substantially white illumination light 98 shown in FIG. Then, the image sensor 48 photographs the observation target using the illumination light 98 including the blue light emitted by the light source device 14 and the wideband green light whose components are adjusted by the optical filter 73.

The blue component B contained in the illumination light 98 is the blue component B of the blue light emitted by the first light source 71, and the purple component V contained in the illumination light 98 is the purple component V of the purple light emitted by the additional light source 74. .. The green component G and the red component R contained in the illumination light 98 are suitable for forming white light from the green component G and the red component R of the wide band green light emitted by the second light source 72 by the optical filter 73. Adjusted to balance. That is, although the light source unit 20 does not have a red light source that emits red light, the red component R of the broadband green light can be used as the red component R of the illumination light 98 to form white illumination light. can.

As described above, the light source device 14 adjusts the balance between the green component G and the red component R of the wide band green light by using the optical filter 73, and uses the red component R of the wide band green light to use the light source unit. The white illumination light 98 can be formed even if the 20 does not have a red light source that emits red light. Therefore, the light source device 14 is more compact than the conventional light source device having a red light source for forming white illumination light because it is not necessary to provide a red light source that emits red light. Further, the light source device 14 is cheaper than the conventional light source device having a red light source for forming the white illumination light 98 because it is not necessary to provide a red light source that emits red light.

In the above embodiment, the light source device 14 and the processor device 16 are separate devices, but since the light source device 14 of the present invention is more compact than the conventional light source device, the light source device 14 and the processor device 16 Can be integrated. For example, as shown in FIG. 10, the light source device 14 and the processor device 16 include an endoscope 12, a light source block 104 composed of each part of the light source device 14, and a processor block 106 composed of each part of the processor device 16. The endoscopic system 101 can be configured by using the integrated control device 102 integrated with the above.

In the above embodiment, the additional light source 74 is provided, but the additional light source 74 can be omitted. For example, when purple light is not used for photographing the observation target, the light source device 14 can be further miniaturized by omitting the additional light source 74.

In the above embodiment, the optical filter 73 adjusts the light amount ratio R / G of the green component G and the red component R of the wide band green light, and as a result, adjusts the brightness ratio of the G image and the R image. However, the brightness ratio of the G image and the R image can be adjusted by combining the arrangement of the color filters of the optical filter 73 and the image sensor 48. For example, as shown in FIG. 11, the color filter of the image sensor 48 usually has an array of R: G: B = 1: 2: 1 in consideration of luminosity factor. On the other hand, as shown in FIG. 12, if the color filter of the image sensor 48 is set to R: G: B = 2: 1: 1 for example, if the G pixel is reduced and the R pixel is increased, the green component G can be obtained. The sensitivity can be lowered and the sensitivity of the red component R can be increased. Therefore, if the image sensor 48 having the color filter array as shown in FIG. 12 is used, the brightness ratio of the G image and the R image can be adjusted by combining the optical filter 73 and the color filter array of the image sensor 48. Can be done. Although FIGS. 11 and 12 take an image sensor 48 having a square array as an example, the same applies to the case where an image sensor 48 having another array such as a so-called honeycomb array image sensor 48 is used.

This also applies when an image sensor 48 having a complementary color filter is used. As shown in FIG. 13, the image sensor 48 having a complementary color filter uses, for example, cyan (C), magenta (M), yellow (Y), and green (G) color filters as C: M: Y. : G = 1: 1: 1: 1. Therefore, as shown in FIG. 14, for example, if the green (G) color filter is replaced with the red (R) color filter, the sensitivity of the green component G can be lowered and the sensitivity of the red component R can be increased. .. Then, if a complementary color image sensor 48 in which the green (G) color filter is replaced with the red (R) color filter is used, the G image and the G image and the arrangement of the color filters of the image sensor 48 can be combined. The brightness ratio of the R image can be adjusted. Although FIGS. 13 and 14 take an image sensor 48 having a square array as an example, the same applies to the case where an image sensor 48 having another array such as a so-called honeycomb array image sensor 48 is used. Further, in the case of the complementary color image sensor 48, instead of replacing the green (G) color filter with the red (R) color filter as described above, as shown in FIG. 15, the yellow (Y) color filter is used. May be replaced with a red (R) color filter. Further, as shown in FIG. 16, the cyan (C) color filter may be replaced with the red (R) color filter. In the arrangement of FIGS. 15 and 16, the sensitivity of the red component R can be relatively increased with respect to the sensitivity of the green component G. As a result, the arrangement of the color filters of the optical filter 73 and the image sensor 48 can be combined. , The brightness ratio of the G image and the R image can be adjusted.

As described above, when the arrangement of the optical filter 73 and the color filter of the image sensor 48 is combined and the brightness ratio of the G image and the R image is adjusted, a wide band green color is formed by the optical filter 73 in order to form white light. It is possible to prevent the green component G of light from being made too small and the noise of the G image from increasing.

In the above embodiment, the optical filter 73 adjusts the light amount ratio R / G of the green component G and the red component R of the wide band green light, and as a result, the brightness ratio of the G image and the R image is adjusted. The brightness ratio of the G image and the R image can be adjusted by combining various processing of the optical filter 73 and the image acquisition unit 54 or the generation processing of the observation image of the image processing unit 61. Specifically, when the light source device 14 is used, the image acquisition unit 54 or the image processing unit 61 uses the red component R rather than the gain applied to the G image obtained by using the green component G to capture the observation target. It is preferable to increase the gain applied to the captured R image and electronically increase the brightness of the R image. In this way, when the brightness of the R image is electronically increased, it is preferable to apply a low-pass filter to the R image. This is because the R image originally has few images of blood vessels and the like, so that the brightness of the R image is electronically increased, and even if a low-pass filter is applied, the effect on the observed image is small. In this way, if the optical filter 73, the increase in the brightness of the R image, and the low-pass filter processing are combined to adjust the brightness ratio of the G image and the R image, the optical filter 73 is used to form white light. Therefore, it is possible to prevent the green component G of the wide band green light from being made too small and the noise of the G image from increasing.

In the above embodiment, the additional light source 74 that emits purple light is provided, but as shown in FIG. 17, the light source device 14 can be further provided with the additional light source 201. The additional light source 201 has the same configuration as the additional light source 74 except that it emits light other than the purple light of the above embodiment. Since the light source device 14 is compact because it is not necessary to provide a red light source that emits red light, the light source device 14 can be configured with the same size as the conventional light source device even if an additional light source 201 is further provided. Of course, if the additional light source 74 that emits purple light is omitted and another additional light source 201 is provided instead, the light source device 14 can be formed more compactly than the conventional light source device.

The additional light source 201 emits light having a difference in the extinction coefficient between the oxidized hemoglobin and the reduced hemoglobin, for example. As shown in FIG. 18, the light having a difference in the extinction coefficient between the oxidized hemoglobin (graph 211) and the reduced hemoglobin (graph 212) is, for example, blue light having a wavelength of about 470 ± 5 nm. The oxygen saturation of the observation target can be measured by using the B image obtained by using the light having a difference in the extinction coefficient between the oxidized hemoglobin and the reduced hemoglobin as the illumination light. Therefore, in addition to the first light source 71 and the second light source 72, if an additional light source 201 that emits light having a difference in the absorption coefficients of the oxidized hemoglobin and the reduced hemoglobin is provided, the oxygen saturation of the observation target is measured. An oxygen saturation observation mode can be added to the endoscope system 10.

The additional light source 201 may be a light source that emits infrared light. In this case, an infrared observation mode for observing the observation target by infrared light or fluorescence generated by the infrared light can be added to the endoscope system 10.

As shown in FIGS. 19 and 20, in addition to the optical filter 73, the light source unit 20 is provided with a second optical filter 301 that dims the red component R of the wideband green light. It is preferable to provide it in the optical path so that it can be freely inserted and removed. If a second optical filter 301 that dims the red component R of wideband green light is provided so that it can be inserted and removed, an R image is unnecessary, and an accurate B image or G image without color mixing of red light is required. Modes can be added to the endoscopic system 10. The observation modes that do not require an R image and require an accurate B or G image without color mixing of red light include, for example, the difference between the B image and the G image, and the B image and the purple component V taken with the blue component B. This is an observation mode in which blood vessels of a specific depth or thickness are extracted and emphasized for observation based on the difference between captured B images.

In FIG. 19, the second optical filter 301 is provided between the second light source 72 and the combine member 77, but as shown in FIG. 21, the second optical filter 301 is attached to the combine member 77. May be provided on the downstream side (between the combiner member 77 and the light guide 41). Further, in FIG. 19, in addition to the optical filter 73, a second optical filter 301 is provided, but instead of the second optical filter 301, as shown in FIGS. 22 and 23, a wide band green light is provided. A second optical filter 302 that dims the red component R from the light can be provided interchangeably with the optical filter 73. The light source control unit 22 controls the insertion and removal of the second optical filters 301 and 302.

In the above embodiment, the present invention is carried out in an endoscope system in which an endoscope 12 provided with an image sensor 48 is inserted into a subject for observation, but the present invention is also performed in a capsule endoscopy system. The invention is suitable. As shown in FIG. 24, for example, in a capsule endoscopy system, a capsule endoscope 400 and a processor device (not shown) are at least included.

The capsule endoscope 400 includes a light source unit 402, a control unit 403, an image sensor 404, an image processing unit 406, and a transmission / reception antenna 408. The light source unit 402 corresponds to the light source unit 20. The control unit 403 functions in the same manner as the light source control unit 22 and the control unit 69. Further, the control unit 403 can communicate wirelessly with the processor device of the capsule endoscopy system by using the transmission / reception antenna 408. The processor device of the capsule endoscopy system is substantially the same as the processor device 16 of the above embodiment, but the image processing unit 406 corresponding to the image acquisition unit 54 and the image processing unit 61 is provided in the capsule endoscope 400 and generated. The observed image is transmitted to the processor device via the transmission / reception antenna 408. The image sensor 404 is the same as the image sensor 48.

In the above-described embodiment and modification, the first light source 71, the second light source 72, the additional light source 74, and the additional light source 201 are all semiconductor light sources such as LEDs, but instead of these semiconductor light sources, Alternatively, in combination with any of these semiconductor light sources, an illumination lamp such as a xenon lamp or another halogen lamp can be used in the light source device 14. This includes the case where the optical filter is moved to the optical path and a specific wavelength region is selectively output from the light emitted by the illumination lamp.

In the above embodiment and the modified example, the second light source 72 emits a wide band green light including the green component G and the red component R, but the light emitted by the second light source 72 emits at least the green component G and the red component. It may contain R, and may also contain a blue component B, a purple component V, an ultraviolet component, or an infrared component. For example, an LED that emits white light (so-called white LED) or the like can be used as the second light source 72. The white light emitted by the white LED has, for example, the spectral spectrum shown in FIG. 25, and the attenuation of the red component R is small as compared with the wideband green light (see FIG. 5) of the above embodiment and the modified example. Further, as shown in FIG. 26, for example, some white LEDs emit white light having a spectral spectrum close to that of natural light (so-called white light having good color rendering properties). A white LED that emits white light having good color rendering properties is suitable for the second light source 72.

In the above embodiments and modifications, the first light source 71, the additional light source 74, and the additional light source 201 include a light emitting element 81 or 86 and a lens 82 or 87, but the first light source 71, the additional light source 74, Similarly to the second light source 72, the additional light source 201 also includes a light emitting element that emits excitation light, a phosphor that emits light emitted by each of the above light sources when the excitation light is incident, and light emitted by the phosphor. It can be configured by a lens that adjusts the light source to parallel light or the like. On the contrary, if the second light source 72 can emit a wide band of green light, the second light source 72 can be composed of a light emitting element and a lens like the first light source 71 and the like. In addition, the first light source 71, the second light source 72, the optical filter 73, the additional light source 74, the combine member 76, the light detectors 91, 92 and 93, the beam splitters 94, 95 and 96, the additional light source 201 and the like. Each part of the light source part 20 can move along the optical axis.

In the above-described embodiment and modification, the optical filter 73 also functions as a wave-binding member of blue light or the like and wide-band green light, but the optical filter 73 is a wave-setting member of blue light or the like and wide-band green light. Separately, an optical filter 73 can be provided. In this case, the optical filter 73 may be arranged in the optical path from the wide band green light emitted by the second light source 72 to the light guide 41, and is preferably arranged at a position before the wavefront with blue light or the like.

10,101 Endoscopic system 12 Endoscope 12a Insertion part 12b Operation part 12c Curved part 12d Tip part 12e Angle knob 13a Zoom operation part 13b Mode changeover switch 14 Light source device 16 Processor device 18 Monitor 19 Console 20,402 Light source unit 22 Light source control unit 30a Illumination optical system 30b Imaging optical system 41 Light guide 45 Illumination lens 46 Objective lens 47 Zoom lens 48,404 Image sensor 54 Image acquisition unit 56 DSP
58 Noise reduction unit 59 Conversion unit 61,406 Image processing unit 66 Display control unit 69,403 Control unit 71 First light source 72 Second light source 73 Optical filter 74,201 Additional light source 76,77 Combined member 81 Light emitting element 82,85 , 87 Lens 83 Light emitting element 84 Phosphorus 86 Light emitting element 91, 92, 93 Optical detector 94, 95, 96 Beam splitter 98 Illumination light 102 Integrated controller 104 Light source block 106 Processor block 211 Graph showing absorption coefficient of hemoglobin oxide 212 Graph showing absorption coefficient of reduced hemoglobin 301, 302 Second optical filter 400 Capsule endoscope 408 Transmission / reception antenna B Blue C Cyan M Magenta Ex Excitation light G Green R Red V Purple Y Yellow

Claims (12)

The first light source that emits blue light and
A second light source that emits a wide band of green light containing a red component in addition to the green component,
An optical filter that adjusts the amount of wideband green light for each wavelength,
With
When the optical filter transmits the wide band green light, the transmittance of the wide band green light or the reflectance of the wide band green light when reflecting the wide band green light is the red component. A light source device that smoothly increases toward the long wavelength side in the range. The second light source includes a light emitting element that emits excitation light and a phosphor that emits the broadband green light when irradiated with the excitation light.
The light source device according to claim 1, wherein the optical filter cuts the excitation light. The light source device according to claim 1 or 2, wherein the optical filter has a stepped change in reflectance or transmittance for each component other than the range of the red component. The light source device according to claim 1 or 2, wherein the optical filter has a smooth change in reflectance or transmittance for each component. The light source device according to any one of claims 1 to 4, wherein the optical filter is a wave combining member that combines the blue light and the broadband green light. The light source device according to any one of claims 1 to 5, further comprising the first light source and the second light source, and an additional light source that emits light having a difference in extinction coefficient between oxidized hemoglobin and reduced hemoglobin. The light source device according to any one of claims 1 to 5, further comprising an additional light source that emits infrared light in addition to the first light source and the second light source. The invention according to any one of claims 1 to 5, further comprising a second optical filter that dims the red component from the broadband green light in addition to or interchangeable with the optical filter. Light source device. The light quantity ratio R / G of the green component G and the red component R of the optical filter the broadband green light after transmitting the light amount of green component G and the red component R of the broadband green light before transmitting through the optical filter The light source device according to any one of claims 1 to 8, which is larger than the ratio R / G. It has a first light source that emits blue light, a second light source that emits broadband green light containing a red component in addition to the green component, and an optical filter that adjusts the amount of the broadband green light for each wavelength. When the optical filter transmits the wide band green light, the transmittance of the wide band green light, or when reflecting the wide band green light, the reflectance of the wide band green light is red. A light source device that smoothly increases toward the long wavelength side in the range of components,
An image sensor that photographs an observation target using the blue light and the wideband green light whose components are adjusted by the optical filter.
Endoscopic system with. The endoscope system according to claim 10, wherein the image sensor is a color sensor having a color filter for each pixel. The internal vision according to claim 10 or 11, wherein the gain applied to the red image obtained by photographing the observation object by using the red component is larger than the gain applied to the green image obtained by photographing the observation object using the green component. Mirror system.

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