WO2021009829A1

WO2021009829A1 - Light source device for endoscope and endoscope device

Info

Publication number: WO2021009829A1
Application number: PCT/JP2019/027865
Authority: WO
Inventors: 伊藤　毅; 山崎　健二; 荘芳斉藤
Original assignee: オリンパス株式会社
Priority date: 2019-07-16
Filing date: 2019-07-16
Publication date: 2021-01-21

Abstract

This light source device for an endoscope comprises a light source unit (140) and a light source controller (150). The light source controller (150) controls the amount of light of four or more light sources of the light source unit (140) on the basis of a light amount ratio set value. The light amount ratio set value is a value that sets a first light amount ratio relating to the color balance of illumination light and a second light amount ratio relating to the degree of emphasis for emphasizing a subject being observed in an area of interest. The four or more light sources include a first light source that emits light having a peak wavelength in a first wavelength range and a second light source that emits light having a peak wavelength in a second wavelength range. In a first same color region, the optical absorption spectrum of the subject being observed in the first wavelength range is relatively larger than the optical absorption spectrum of the subject being observed in the second wavelength range.

Description

Light source device for endoscopes and endoscope device

The present invention relates to a light source device for an endoscope, an endoscope device, and the like.

In the light source device used for the endoscope device, a method using a plurality of light sources that emit light having different wavelengths is known. Such a light source device is disclosed in, for example, Patent Document 1. The light source device of Patent Document 1 includes a blue laser, a green laser, and a red laser, the wavelength of the blue laser is the peak wavelength of the hemoglobin absorption spectrum, and the wavelength of the green laser and the red laser is the non-peak of the hemoglobin absorption spectrum. The wavelength. The blue laser improves the visibility of the surface blood vessels, and the illumination light has whiteness due to the light amount ratio of the blue laser, the green laser, and the red laser.

International Publication No. 17/061003

There is a problem of achieving both visibility and whiteness of lesions in the illumination light of the endoscope device. Specifically, conventionally, a xenon lamp or the like having a continuous spectrum has been used as a white light source in an endoscope device. In order to utilize the knowledge of observation, diagnosis or screening using such a general white light source, it is required to maintain the function as white light. The function as white light is, for example, lesion drawing output or color tone of an image. When a suspicious lesion is found by observing white light, the doctor will switch to the special light observation mode for examination, but if the suspicious lesion is not noticed by observing white light, it may be overlooked. .. Therefore, the illumination light is required to have a lesion drawing output.

One aspect of the present invention includes a light source unit that emits light having peak wavelengths different from each other and includes four or more light sources that can independently control the amount of light of each light source and generates illumination light to irradiate an observation object. The light amount ratio setting value includes a light source controller that controls the light amount of the four or more light sources based on the light amount ratio setting value that sets the light amount ratio of the four or more light sources, and the light amount ratio setting value relates to the color balance of the illumination light. It is a value that sets the first light amount ratio and the second light amount ratio regarding the degree of emphasis that the illumination light emphasizes the observation object in the region of interest, and the light sources of 4 or more peak in the first wavelength region. A first light source that emits light having a wavelength and a second light source that emits light having a peak wavelength in the second wavelength region are included, and the first wavelength region and the second wavelength region are blue region and green. In the first same color region, the absorption intensity of the light absorption spectrum of the observation object in the first wavelength region is in the second wavelength region. It is relatively larger than the absorption intensity of the light absorption spectrum of the observation object, and the first light amount ratio is blue light amount which is the light amount of the illumination light in the blue region and green which is the light amount of the illumination light in the green region. It relates to a light source device for an endoscope, which is a ratio of the amount of light and the amount of red light, which is the amount of illumination light in the red region.

Further, another aspect of the present invention relates to an endoscope device including the above-mentioned light source device for an endoscope and an imaging unit for imaging the observation object irradiated with the illumination light.

Configuration example of the endoscope device. An example of the spectrum of illumination light in the basic configuration. An example of setting the second light intensity ratio that satisfies the visibility improvement requirement. Light absorption spectrum of hemoglobin. The figure explaining the division of the visible light wavelength region by the combination of the visibility improvement wavelength region and the color region. Detailed configuration example of the light source device. An example of the illumination light spectrum in the first embodiment. An example of wavelength characteristics of a blue-green region cut filter. An example of the spectrum of illumination light when a blue-green region cut filter is inserted into the optical path. Examples of transmittance characteristics of the dichroic filter in the first embodiment and the second embodiment. An example of wavelength characteristics of a dichroic filter in a modified example of the second embodiment. Absorption spectrum of indocyanine green. An example of an illumination light spectrum that emphasizes indocyanine green. Absorption spectrum of indigo carmine. An example of an illumination light spectrum that emphasizes indigo carmine. Absorption spectrum of crystal violet. An example of an illumination light spectrum that emphasizes crystal violet. Absorption spectrum of Lugol's solution. An example of an illumination light spectrum that emphasizes Lugol's solution.

Hereinafter, this embodiment will be described. The present embodiment described below does not unreasonably limit the content of the present invention described in the claims. Moreover, not all of the configurations described in the present embodiment are essential constituent requirements of the present invention.

1. 1. Endoscope device FIG. 1 is a configuration example of the endoscope device 10. In the following, the configuration and operation common to general endoscopes will be omitted, and the features related to the present invention will be mainly described. In the following, a medical endoscope for digestive organs will be described as an example, but the scope of application of the present invention is not limited to this. That is, the endoscope referred to in the present specification refers to a general device provided with an insertion portion for observing the inner surfaces of recesses of various subjects. For example, an endoscope is a medical endoscope used for examination or surgery of a living body.

The endoscope device 10 of FIG. 1 includes a control device 100, a scope 200, a display unit 300, and an input unit 600. The display unit 300 is also referred to as a display or a display device. The input unit 600 is also called an input device or an operation device. First, the configuration of the endoscope device 10 will be described.

The scope 200 is composed of an insertion unit 210, an operation unit 220, a connection cable 230, and a connector 240. The insertion portion 210 has flexibility and can be inserted into the body cavity of a living body. The body cavity of the living body is the subject in the present embodiment. A user such as a doctor grips the operation unit 220 and operates the endoscope device 10 using the operation unit 220. The connection cable 230 is a cable that connects the control device 100 and the scope 200, and has flexibility. The connector 240 is provided at one end of the connection cable 230, and makes the control device 100 and the scope 200 detachable.

At the tip of the insertion portion 210, there are

illumination lenses

211 and 212 that emit illumination light toward the subject, and an imaging unit 213 that captures an image by receiving the illumination light reflected or scattered from the surface of the subject. Have been placed.

The scope 200 is provided with a light guide 214. The light guide 214 is optically connected to the

illumination lenses

211 and 212. The control device 100 is provided with a light source unit 140, and the light guide 214 guides the illumination light emitted from the light source unit 140 to the

illumination lenses

211 and 212. The light guide 214 is a light guide for an optical fiber bundle or the like. The light guide extends from the connector 240 to the

illumination lenses

211 and 212 via the connection cable 230 and the operation unit 220.

The

illumination lenses

211 and 212 spread the illumination light guided by the light guide so as to have a desired radiation angle. Each of the

illumination lenses

211 and 212 is an illumination optical system composed of a single lens or a plurality of lenses.

The image pickup unit 213 has an image pickup optical system and an image pickup element. The image sensor is, for example, a CMOS image sensor. The imager is a Bayer type imager equipped with RGB primary color filters arranged in a Bayer type, a complementary color imager equipped with a complementary color filter, or a monochrome imager. Monochrome imagers are used for surface-sequential scopes. In addition to the CMOS imager, it is also possible to use a CCD as the image sensor.

The scope 200 is provided with an image signal line 215, and transmits the image signal of the image captured by the image pickup unit 213 to the control device 100. The image signal line 215 is arranged in the insertion unit 210, the operation unit 220, and the connection cable 230, and is connected so as to be able to transmit a video signal to the control device 100 via the connector 240. The image signal line 215 may be an optical fiber or the like for optical communication.

The control device 100 includes a light source device 160 that emits illumination light and a processing circuit 110. The processing circuit 110 performs image processing on the image signal from the image pickup unit 213 and controls each part of the endoscope device 10.

The processing circuit 110 is realized by a circuit device in which a plurality of circuit components are mounted on a board. Alternatively, the processing circuit 110 may be a processor or an integrated circuit device such as an ASIC (Application Specific Integrated Circuit). When the processing circuit 110 is a processor, the operation of the processing circuit 110 is realized by the processor executing a program that describes the operation of the processing circuit 110. The program is stored in, for example, a memory (not shown).

The display unit 300 displays an image of the subject image processed by the processing circuit 110. The display unit 300 is a variety of commonly used display devices, such as a liquid crystal monitor. The display unit 300 is electrically connected to the control device 100 by an electrical wiring that transmits an image signal.

The input unit 600 receives an operation from the user and outputs the operation information to the processing circuit 110. The input unit 600 is, for example, a button or dial, a keyboard, a mouse, a touch panel, or the like. The touch panel may be provided on the display unit 300. Alternatively, the input unit 600 may be an interface connected to an information processing device such as a PC (Personal Computer). The interface receives the input information from the information processing apparatus and outputs the input information to the processing circuit 110. The interface is, for example, a communication interface such as USB (Universal Serial Bus) or LAN (Local Area Network).

The light source device 160 includes a light source unit 140 that emits illumination light and a light source controller 150 that controls the light source unit 140.

The light source unit 140 has four or more light sources that emit four or more lights having different wavelengths from each other. The light source unit 140 enters the scope 200 using the four or more lights as illumination light. Each light source is, for example, an LED (Light Emitting Diode), a semiconductor laser, or an SLD (Super Luminescent Diode). Alternatively, each light source may be a light source in which a laser and a phosphor are combined. By using SLD, it is possible to realize a light source having a narrower wavelength region and higher brightness than LED. In addition, by combining a phosphor and a laser, light of various wavelengths can be emitted with high brightness. By using a laser, high-intensity light can be guided to a light guide with high efficiency. Alternatively, a light source that combines lamp light and a filter may be used. The filter is provided on the optical path from the lamp to the incident end of the light guide. For example, the rotation filter has a plurality of filters having different transmission wavelengths from each other, and the rotation of the rotation filter realizes the emitted light of each light source.

The wavelength region of visible light includes a red region, a green region, and a blue region. One of the four or more lights constituting the illumination light belongs to each of these regions. In addition, two or more of the four or more lights belong to any of the red region, the green region, and the blue region. Hereinafter, the color region to which the two or more lights belong is referred to as a first same color region. Of the two or more lights belonging to the first same color region, one has a peak wavelength in the first wavelength region and the other has a peak wavelength in the second wavelength region. A light source that emits light having a peak wavelength in the first wavelength region is called a first light source, and a light source that emits light having a peak wavelength in the second wavelength region is called a second light source. A detailed example of the illumination light will be described later.

In the above first same color region, the absorption intensity of the light absorption spectrum of the observation object in the first wavelength region is relatively larger than the absorption intensity of the light absorption spectrum of the observation object in the second wavelength region. Hereinafter, the first wavelength region is also referred to as a visibility improving wavelength region, and the second wavelength region is also referred to as a visibility non-improving wavelength region. The visibility-enhancing wavelength region is a wavelength region that emphasizes the observation object in the light absorption spectrum of the observation object existing in the region of interest (ROI: Region Of Interest). By emphasizing the observation object in the region of interest with the illumination light, the visibility of the region of interest is enhanced in the image in which the region of interest is captured. The area of interest is an area of interest of a doctor in a subject, for example, a lesion that is desired to be found in screening, a lesion that is the target of examination or treatment, or a tissue that is to be identified in examination or treatment. The object to be observed is a substance or a drug contained in a living body. The substance contained in the living body is, for example, hemoglobin or β-carotene. The drug is sprayed on the surface of the subject or injected into a blood vessel. The agent is, for example, indocyanine green, indigo carmine, crystal violet or Lugol's solution. The object to be observed is not limited to any one of the above, and may be at least one of the above. That is, the observation object may include two or more of the above.

The light source controller 150 can include, for example, a drive circuit that drives the light source and a control circuit or processor that controls the drive circuit. Alternatively, when the light source includes a drive circuit, the light source controller 150 may be a control circuit or a processor that controls the drive circuit of the light source.

The light source controller 150 independently adjusts the light intensity of each of the above 4 or more lights based on the light intensity ratio set value. The light amount ratio setting value is a value for setting the first light amount ratio and the second light amount ratio. The first light amount ratio relates to the color balance of the illumination light. The second light amount ratio relates to the degree of emphasis that the illumination light emphasizes the observation object in the region of interest. The first light amount ratio is the ratio of the blue light amount, the green light amount, and the red light amount. The amount of blue light is the amount of illumination light in the blue region, the amount of green light is the amount of illumination light in the green region, and the amount of red light is the amount of illumination light in the red region. The second light amount ratio is the light amount ratio of the first light source and the second light source determined based on the magnitude relationship in the light absorption spectrum of the observation object. That is, the second light amount ratio is a light amount ratio of light having a peak wavelength in the visibility improving wavelength region and light having a peak wavelength in the visibility non-improving wavelength region.

The light source controller 150 adjusts the color balance of the illumination light and the degree of emphasis of the region of interest by adjusting the light amount ratio of 4 or more based on the light amount ratio set value. The color balance is the balance of red, green, and blue in the illumination light, for example, the color temperature of the illumination light. The degree of emphasis is the contrast between the observation object in the region of interest and the other region. That is, since the illumination light is absorbed based on the absorption spectrum of the observation object, the observation object has a larger absorbance than the other regions. As a result, the observation object becomes darker than the other areas, so that a contrast between the observation object and the other areas occurs. This contrast emphasizes the area of interest that includes the object to be observed.

The light amount ratio set value may be one light amount ratio that realizes the first light amount ratio and the second light amount ratio at the same time, or the first light amount ratio and the second light amount ratio are specified separately. May be good. For example, a semiconductor light source has a correlation between a current value and a light emission amount. In this case, the light amount ratio setting value may specify the current value that realizes the first light amount ratio and the second light amount ratio. For example, the light amount ratio set value is stored in the light amount ratio storage unit. The light amount ratio storage unit is included in the light source device 160, and is included in, for example, the light source controller 150 as described later. The light source controller 150 controls the illumination light based on the light amount ratio set value read from the light amount ratio storage unit. Alternatively, the light amount ratio set value is input to the processing circuit 110 via the input unit 600. The light source controller 150 controls the illumination light based on the light amount ratio set value from the processing circuit 110.

Various methods can be assumed in which the light source controller 150 controls the amount of light emitted from the light source. For example, when the light source is a light emitting diode, there are methods such as current dimming or PWM dimming, pulse number dimming, and a combination thereof. In current dimming, the light source controller 150 adjusts the amount of light by changing the drive current that drives the light emitting diode. In PWM dimming, the light source controller 150 adjusts the amount of light by changing the light emission time within a predetermined imaging period. In pulse number dimming, the light source controller 150 adjusts the amount of light by changing the number of pulses to be emitted within a predetermined imaging period. Further, the light source controller 150 may use two or three of these three dimming methods in combination.

When the illumination light is generated using a plurality of light sources as described above, there is a problem that the whiteness of the illumination light and the emphasis of the area of interest are both desired. For example, a user of an endoscopic apparatus makes a diagnosis based on the color of a subject in an endoscopic image, and in the diagnosis, the literature or past experience is referred to. At this time, the whiteness of the illumination light is required in order to utilize the literature or past experience. Further, in order to make it easier to find the area of interest in screening, or to make it easier to see the area of interest in examination or treatment, it is required to emphasize the area of interest with illumination light.

In this regard, according to the present embodiment, the light source controller 150 adjusts the light amount ratio of four or more lights constituting the illumination light based on the light amount ratio set value to enhance the color balance of the illumination light and the region of interest. Adjust the degree. This makes it possible to independently adjust the color balance of the illumination light and the degree of emphasis of the region of interest. For example, by adjusting the light amount ratio of four or more lights constituting the illumination light, it is possible to realize whiteness that makes the best use of literature or past experience, and to emphasize the region of interest by the illumination light.

Specifically, the light source controller 150 adjusts the ratio of the amount of blue light, the amount of green light, and the amount of red light based on the first light amount ratio. Moreover, the light source controller 150 adjusts the amount of light of two or more lights belonging to the same color region based on the second light amount ratio.

As described above, the first light amount ratio is the light amount ratio that sets the color balance of the illumination light, and the second light amount ratio is the light amount ratio that sets the degree of emphasis of the region of interest. That is, the light source controller 150 sets the color balance of the illumination light by the first light amount ratio, and adjusts the emphasis degree of the region of interest based on the second light amount ratio while maintaining the color balance. As a result, the color balance of the illumination light and the degree of emphasis of the area of interest are adjusted independently, and the target color balance and the degree of emphasis of the area of interest are realized.

The detailed embodiment will be described below. The following plurality of embodiments may be combined as appropriate.

2. 2. Basic configuration FIG. 2 is an example of a spectrum of illumination light in the basic configuration. Here, an example of using six color light sources having different peak wavelengths will be described.

As shown in FIG. 2, the visible light region is divided into a blue region, a green region, and a red region. The light source unit 140 generates two narrow wavelength region lights in each color region. The light source unit 140 includes six light sources that generate light IV, IB, IG1, IG2, IA, and IR. The light IV and IB belong to the wavelength regions BV and BB obtained by dividing the blue region. BV is on the shorter wavelength side than BB. The optical IG1 and IG2 belong to the wavelength regions BG1 and BG2 in which the green region is divided. BG1 is on the shorter wavelength side than BG2. The optical IA and IR belong to the wavelength regions BA and BR in which the red region is divided. BA is on the shorter wavelength side than BR.

As shown in FIG. 2, the spectrum of each light and the spectrum adjacent to it are in contact with each other at the hem. That is, there is no region where there is no light component over the entire wavelength region of visible light, and there is no region where the wavelength component is missing in the illumination light.

Each region of BV, BB, BG1, BG2, BA, and BR corresponds to the spectral characteristics of the region of interest. Specifically, each wavelength region of BV, BG2, and RA is a visibility improvement wavelength region corresponding to a wavelength region in which visibility can be improved. Each of the wavelength regions of BB, BG1, and BR is a non-improved visibility wavelength region corresponding to a wavelength region in which visibility is not relatively improved as compared with the “improved visibility wavelength region”.

Light in the blue region is absorbed and scattered on the surface layer of the living body as compared with light in other color regions. Light in the green region is absorbed and scattered in the middle layer of the living body as compared with light in other color regions. Light in the red region is absorbed and scattered in the deep layers of the living body as compared with light in other color regions. As a result, the light IV included in the wavelength region BV can improve the visibility of the region of interest relatively included in the surface layer. Similarly, the optical IG2 included in the wavelength region BG2 can improve the visibility of the region of interest relatively included in the middle layer. Similarly, the optical IA included in the wavelength region BA can improve the visibility of the region of interest included in a relatively deep layer. Therefore, by setting the light amounts of IV, IG2, and IA relatively large, the visibility of the region of interest can be improved. This requirement is called the visibility improvement requirement.

The light intensity ratio of IV + IB: IG1 + IG2: IA + IR is the above-mentioned first light intensity ratio. The first light intensity ratio is about the same as the light intensity ratio of the blue region, the green region, and the red region in the white light source. The white light source is a xenon lamp or a halogen lamp. White illumination light is realized by this first light amount ratio. Further, by emitting not only the light in the wavelength region with improved visibility but also the light in the wavelength region with non-improved visibility, it is possible to realize the hue and naturalness of the observed image.

For example, apparent white light can be realized with three colors of light IV, IG2, and IA. However, since the wavelength regions of light IB, IG1, and IR are missing, the colors do not look natural depending on the type of subject. For example, a subject having high reflectance in the wavelength regions BB, BG1 and BR and low reflectance in the wavelength regions BV, BG2 and BA is observed. When such a subject is viewed only with light IV, IG2, and IA, the image becomes unnaturally darker than when viewed with normal white light, and the hue when viewed with normal white light is lost. I will be broken. According to the present embodiment, since the spectrum has almost no omission over the entire visible light region, a natural hue can be maintained. If there is no lack of wavelength, it is possible to realize a natural hue by combining with appropriate image processing, even if the spectrum is not necessarily broad.

FIG. 3 is an example of setting the second light intensity ratio that satisfies the visibility improvement requirement. As shown in FIG. 3, the light amount ratio in the blue region is IV: IB≈2: 1, the light intensity ratio in the green region is IG1: IG2≈1: 2, and the light intensity ratio in the red region is IA: IR≈2. It is 1. Further, in order to satisfy the white light requirement, the light amount ratio between the color regions is IB1 + IB2: IG1 + IG2: IR1 + IR2 ≈ 1: 1: 1. As a result, both can be satisfied.

With this configuration, it is possible to improve the visibility of the virtual area of interest and to realize a light source that has the same hue and naturalness as conventional white light observation.

Note that the same color region to which the above two or more lights belong may be any of a blue region, a green region, and a red region in FIG. For example, when the blue region is the same color region, the first wavelength region is BV, the second wavelength region is BB, the light source that emits IV is the first light source, and the light source that emits IB is the second light source. Is.

Further, in FIGS. 2 and 3, the illumination light is composed of 6 bands of light, but the illumination light may be composed of 4 or more bands of light. In the case of four bands, one or more lights belong to each of the blue region, the green region, and the red region, and two lights belong to only one of the color regions. An example in the case of 5 bands will be described later in the first embodiment.

3. 3. Visibility Improvement Requirements and White Light Requirements The details of the visibility improvement requirements and white light requirements will be explained.

The visibility improvement requirements are the following requirements A and B. Requirement B is not mandatory but a desirable requirement. The visibility improvement requirement defines the above-mentioned second light intensity ratio.

Requirement A: The intensity of light in the wavelength region that contributes to improving the visibility of the region of interest is relatively higher than the intensity of light in the other wavelength regions. For example, light in a wavelength region that contributes to improved visibility can be selected based on the spectral spectrum in the region of interest. In the example of FIG. 3, IV light amount> IB light amount, IG1 light amount <IG2 light amount, IA light amount> IR light amount. It should be noted that the requirement A is not limited to the case where the requirement A is satisfied in all the color regions, and the requirement A may be satisfied in any one color region.

Requirement B: Light in the wavelength region that contributes to improving the visibility of the region of interest exists in any of the blue region, the green region, and the red region.

The white light requirements are the following requirements C, D, and E. Requirement E is not mandatory but a desirable requirement. The white light requirement is a requirement for realizing a hue or naturalness as white light, and defines the above-mentioned first light amount ratio.

Requirement C: Light components are present in any of the blue region, green region, and red region.

Requirement D: Blue light amount: Green light amount: Red light amount is a ratio of approximately white. That is, this ratio is set to be substantially equal to the light amount ratio of the illumination light used in a conventional endoscope such as a xenon lamp, a halogen lamp, or a white LED. The ratio of the illumination light may be within a range that can be adjusted to a white balance equivalent to white light in image processing.

Requirement E: The spectrum of illumination light is a substantially continuous spectrum in the visible light wavelength region. The spectrum does not have to be flat, but there is almost no wavelength region where the amount of light is zero. If there is no light in the wavelength region that improves the visibility of the region of interest in any of the blue region, green region, and red region, the hue or naturalness of white light is given priority. The spectrum or the amount of light may be set.

As an example, the visible light wavelength region of 400 nm to 700 nm is divided into a blue region, a green region, and a red region. The light intensity ratio of the light contained in each color region is set based on the white light requirements of requirements C to E. For example, blue light amount: green light amount: red light amount ≈ 1: 1: 1. Alternatively, the amount of blue light: the amount of green light: the amount of red light may be set to a light amount ratio substantially equal to the color balance in the white light (normal light) of a commercially available endoscope.

Further, the spectrum pattern in each color region is set based on the visibility improvement requirements of requirements A and B. For example, at least one color region of the blue region, the green region, and the red region contains two or more narrow wavelength region lights. The narrow wavelength region light has a full width at half maximum of 50 nm or less. The light intensity ratio of two or more narrow wavelength region lights belonging to the same color region is set based on which wavelength region contributes to the improvement of visibility.

For example, when the subject is a living body, the depth at which the illumination light travels inside the living body tissue differs depending on the wavelength. That is, light having a short wavelength such as blue can travel only to the surface layer, but travels from the middle layer to the deep layer as the wavelength becomes longer. When the region of interest is concentrated on the surface layer or deep layer of living tissue, only the light in the color region that can travel to that depth contributes to the improvement of visibility. When the region of interest extends from the surface layer to the deep layer, light of a plurality of wavelengths corresponding to each depth contributes to the improvement of visibility.

When observing a plurality of areas of interest, the spectral pattern can be set based on the spectral characteristics of each area of interest or the depth at which each area of interest exists. In this case, the spectrum pattern is set from information such as wavelengths that contribute to improving the visibility of each region of interest and wavelengths that do not.

If there is a color region that does not improve visibility, it is advisable to prioritize the hue or naturalness of white light and use the illumination light in that color region as light with a broad spectrum.

Areas of interest include, for example, areas where the color tone has changed compared to normal mucosa, blood vessel patterns, blood vessel structures, surface structures of living tissues, and the like. The light amount ratio in each color region is set so as to improve the visibility of these attention regions.

4. First Embodiment The first embodiment will be described with an example of assuming a shape or pattern of a blood vessel as a region of interest. That is, in the first embodiment, the observation object included in the region of interest is hemoglobin.

FIG. 4 is a light absorption spectrum of hemoglobin contained in blood. The dotted HBA is the absorption spectrum of oxidized hemoglobin associated with oxygen. HBB shown by a solid line is an absorption spectrum of reduced hemoglobin from which oxygen has been removed.

As shown in FIG. 4, the two spectra HBA and HBB have substantially similar characteristics. That is, the spectra HBA and HBB have maximum absorption in the range of 410 nm to 440 nm and 520 to 580 nm, and minimum absorption in the range of 470 nm to 500 nm and 630 nm to 720 nm. On the longer wavelength side than 730 nm, the spectrum HBB of reduced hemoglobin has a maximum near 750 nm, and the absorbance of the oxidized hemoglobin spectrum HBA gradually increases toward the long wavelength side.

Light having a peak near the maximum of the absorption spectrum has a higher rate of absorption by hemoglobin than light in other wavelength regions. Therefore, when observed with light having a peak near the maximum of the absorption spectrum, the contrast between the blood vessel and the surrounding tissue becomes high. As a result, the visibility of blood vessels containing a large amount of hemoglobin is relatively improved. On the contrary, light having a peak near the minimum of the absorption spectrum is less likely to be absorbed by hemoglobin as compared with light in other wavelength regions. Therefore, when observing with light having a peak near the minimum of the absorption spectrum, the contrast between the blood vessel and the surrounding tissue becomes low, so that the visibility of the blood vessel becomes low.

According to the absorption spectrum of hemoglobin shown in FIG. 4, the visible light wavelength region is divided into the following wavelength regions. λ is the wavelength.
Visibility improvement region VA: 400 nm ≤ λ <450 nm
Non-visibility improvement region NVA: 450 nm ≤ λ <510 nm
Visibility improvement region VB: 510 nm ≤ λ <615 nm
Non-visibility improvement region NVB: 615 nm ≤ λ <740 nm
Visibility improvement region VC: 740 nm ≤ λ <790 nm

The visibility improvement region VA is a wavelength region including an absorption maximum in the vicinity of 410 nm to 440 nm. The non-visibility improvement region NVA is a wavelength region including an absorption minimum in the vicinity of 470 nm to 500 nm. The light in the vicinity of 440 nm to 470 nm, which is the boundary region between the visibility improving region VA and the non-visibility improving region NVA, slightly improves the visibility of blood vessels, but does not significantly improve it. In the present embodiment, this wavelength region is included in VA and NVA with 450 nm as a boundary, but the wavelength of the boundary may be arbitrary between 440 nm and 470 nm.

The visibility improvement region VB is a wavelength region including an absorption maximum in the vicinity of 520 nm to 580 nm, and is set to 510 nm to 615 nm including the boundary region. The non-visibility improvement region NVB is a wavelength region including an absorption minimum in the vicinity of 630 nm to 730 nm, and is set to 615 nm to 740 nm including the boundary region.

The visibility improvement region VC is a wavelength region including the absorption maximum of reduced hemoglobin, and is set to a wavelength region longer than 740 nm.

Visibility improvement area When illuminated with light of wavelengths included in VA, VB, and VC, the visibility of blood vessels is relatively improved. On the other hand, when illuminated with light having a wavelength included in the non-visibility improving regions NVA and NVB, it is difficult to improve the visibility of blood vessels.

As a supplement, when illuminating a living body like an endoscope, the penetration depth of light into the living body differs depending on the wavelength. That is, light on the short wavelength side is easily absorbed / scattered on the surface of living tissue, and as the wavelength becomes longer, it easily penetrates deep inside the living body. For example, blood vessels in the stomach and intestines have thin capillaries near the surface and slightly thick blood vessels in the middle to deep layers. Therefore, the visibility of the blood vessels on the surface layer is improved by the light in the wavelength region of the visibility improvement region VA. Visibility improvement region Light in the wavelength region of VB improves the visibility of blood vessels in the middle layer. Visibility Improvement Region The visibility of deep blood vessels is improved by the light in the wavelength region of VC.

Next, the hue and naturalness of white light will be explained.

Generally, as the illumination light used for observing the endoscope, visible light having a diameter of about 400 nm to 680 m is used. This visible light region is generally classified into three color regions, a blue region, a green region, and a blue region. For example, it can be classified as follows based on the spectral characteristics of the color filter of the image sensor. λ is the wavelength.
Blue region: 400 nm ≤ λ <495 nm
Green region: 495 nm ≤ λ <585 nm
Red region: 585 nm ≤ λ <680 nm

The illumination light becomes white light when the amount of light in these three color regions is approximately 1: 1: 1. At this time, the spectral spectrum in each color region does not necessarily have to be broad, and may be illumination light having a maximum and a minimum. Further, even if there is a wavelength loss, white as illumination light can be realized.

However, if there is an extremely narrow wavelength region light or a large wavelength missing region that is a wavelength region without a light emitting component, the color tone may be uncomfortable depending on the subject. By observing the subject with illumination light such that there is almost no wavelength loss and R: G: B≈1: 1: 1, a natural hue and a natural hue can be realized.

A combination of a xenon lamp, a halogen lamp, a white LED, or a multicolor LED is used in a general endoscope. In each case, the amount of blue light: the amount of green light: the amount of red light ≈ 1: 1: 1. By combining this condition with appropriate image processing, an endoscopic image having natural whiteness is realized.

The missing wavelength will be explained in a little more detail.

The light of xenon lamps and halogen lamps generally used in conventional endoscopes is generally broad in the visible light wavelength region, and there is no wavelength loss. On the other hand, in the case of illumination light in which a plurality of narrow wavelength region lights are combined, wavelength omission exists depending on the wavelength and spectrum width of the LED. When observing with illumination light having a missing wavelength, the color information of the subject in the missing wavelength region cannot be acquired. Therefore, there is a possibility that color information will be lost as compared with the case of observing with illumination light having no wavelength loss. In the biological tissue that is the subject of the medical endoscope, the spectral reflectance is also continuous, so the effect of wavelength loss is not large, but the color information is still missing, so compared to normal light observation light. The color of the image may change. In this embodiment, as will be described later, a continuous spectrum having no wavelength loss in the visible light wavelength region or a spectrum having substantially no wavelength loss is used. Therefore, the change in color due to the lack of color information is small.

Compared to a broad illumination light such as a xenon lamp, the color of the illumination light with peaks and bottoms in the spectrum may change. However, since the color information in the bottom region is not zero, the color information in the bottom region can be acquired. Therefore, by combining with appropriate image processing, it is possible to provide an image equivalent to that in the case of broad illumination light.

FIG. 5 is a diagram illustrating division of a visible light wavelength region by a combination of a visibility improving wavelength region and a color region. It is divided into the following six wavelength regions by the combination of the visibility improving wavelength region and the color region. λ is the wavelength.
Wavelength region RA: A wavelength region included in the visibility improvement region VA in the blue region. 400nm ≤ λ <450nm
Wavelength region RB: A wavelength region included in the invisible improvement region NVA in the blue region. 450nm ≤ λ <495nm
Wavelength region RC: A wavelength region included in the invisible improvement region NVA in the green region. 495nm ≤ λ <510nm
Wavelength region RD: A wavelength region included in the visibility improvement region VB in the green region. 510 nm ≤ λ <585 nm
Wavelength region RE: A wavelength region included in the visibility improvement region VB in the red region. 585 nm ≤ λ <615 nm
Wavelength region RF: A wavelength region included in the invisible improvement region NVB in the red region. 615 nm ≤ λ <680 nm

As shown in FIGS. 4 and 5, in the blue region, the absorption spectrum of the wavelength region RA belonging to the visibility improving region is larger than the absorption spectrum of the wavelength region RB belonging to the non-visibility improving region. In the green region, the absorption spectrum of the wavelength region RD belonging to the visibility improving region is larger than the absorption spectrum of the wavelength region RC belonging to the non-visibility improving region. In the red region, the absorption spectrum of the wavelength region RE belonging to the visibility improving region is larger than the absorption spectrum of the wavelength region RF belonging to the non-visibility improving region. Here, the magnitude of the absorption spectrum is compared with the maximum value of the spectrum in the wavelength region. Alternatively, the magnitude of the absorption spectrum may be compared by the average value of the spectra in the wavelength region.

Since visible light illumination is targeted in this embodiment, the near-ultraviolet region of less than 400 nm and the near-infrared region of more than 680 nm are not mentioned. However, near-infrared light is effective when observing blood vessels in a deeper layer. At this time, by using the wavelength included in the visibility improvement region VC, the visibility improvement effect can be achieved. Further, by using near-ultraviolet light of 380 nm to 400 nm, there is a possibility that blood vessels in the polar surface layer can be observed with good contrast.

FIG. 6 is a detailed configuration example of the light source device 160. Note that only the connector of the scope 200 and the light guide 214 are shown in FIG. 6, and the other components are not shown.

The light source unit 140 includes a light source LDV that emits purple light IV, a light source LDB that emits blue light IB, a light source LDG that emits green light IG, a light source LDA that emits amber light IA, and red. Includes a light source LDR that emits the light IR of the above, and an optical combine unit 141. Further, the light source unit 140 may further include a lens or the like for changing the light distribution of the light source or making it parallel light.

The light combining unit 141 combines the above five colors of light and causes the light guide 214 to enter the incident end. The optical combiner section 141 is a dichroic filter DC1 to DC4 that combine light IV, IB, IG, IA, and IR. Alternatively, the optical combiner 141 may be an optical fiber or an optical fiber bundle having five incident ends and one outgoing end. The LED light incident on the light guide 214 is guided to the tip of the scope by the light guide 214 and is irradiated toward the subject.

The light sources LDV and LDB are InGaN-based LEDs. The light sources LDA and LDR are AlGaInP-based LEDs. The light source LDG is a so-called hybrid type LED in which an InGaN-based blue LED is used as excitation light and green light is emitted from a phosphor coated on the LED light emitting surface.

Each LED of the light source LDV, LDB, LDA, and LDR generates light in a narrow wavelength region having a half width of about 20 to 40 nm. The LED of the light source LDG emits relatively broad wide wavelength region light having a half width of 50 nm or more. The peak wavelengths of the light generated by the light sources LDV, LDB, LDG, LDA, and LDR are 415 nm, 460 nm, 540 nm, 600 nm, and 630 nm, respectively.

FIG. 7 is an example of the illumination light spectrum in the first embodiment.

As shown in FIGS. 5 and 7, in the present embodiment, the light IV having a peak wavelength of 415 nm generated by the light source LDV is included in the wavelength region RA that relatively improves visibility. The light IB having a peak wavelength of 460 nm generated by the light source LDB is included in the wavelength region RB that does not relatively improve visibility. The optical IG having a peak wavelength of 540 nm generated by the light source LDG is included in the wavelength region RD that relatively improves visibility. The light IA having a peak wavelength of 600 nm generated by the light source LDA is included in the wavelength region RE that relatively improves visibility. The optical IR having a peak wavelength of 630 nm generated by the light source LDR is included in the wavelength region RF that does not relatively improve visibility.

The light source controller 150 emits light from the light sources LDV, LDB, LDG, LDA, and LDR by outputting a drive current to the light sources LDV, LDB, LDG, LDA, and LDR. When the scope is a surface-sequential system, the light source controller 150 sequentially causes the light sources LDV, LDB, LDG, LDA, and LDR to emit light according to a predetermined light emission sequence. When the image sensor of the scope is a primary color Bayer type or a complementary color type, the light source controller 150 simultaneously emits light sources LDV, LDB, LDG, LDA, and LDR.

The light source controller 150 includes a light amount ratio storage unit 151 and a light amount ratio control circuit 152.

The light amount ratio storage unit 151 stores the light amount ratio set value. For example, the light amount ratio set value is written in advance in the light amount ratio storage unit 151 at the time of manufacturing the endoscope device. Various storage devices can be assumed as the light amount ratio storage unit 151. For example, the light amount ratio storage unit 151 is a semiconductor memory such as a RAM or ROM or a non-volatile memory. Alternatively, the light amount ratio storage unit 151 may be a magnetic storage device such as a hard disk drive.

The light amount ratio control circuit 152 controls the light amount ratio of the light emitted by the light sources LDV, LDB, LDG, LDA, and LDR based on the light amount ratio set value read from the light amount ratio storage unit 151. As described above, the light amount ratio set value includes the first light amount ratio and the second light amount ratio. The color balance is set by the first light intensity ratio, and the degree of emphasis of the region of interest is set by the second light intensity ratio.

The endoscope device of the present embodiment can switch between several observation modes according to the purpose. That is, it is possible to selectively switch between a screening mode, a WLI (White Light Imaging) mode, and three types of special light observation modes. The screening mode is also referred to as a first normal light observation mode, and the WLI mode is also referred to as a second normal light observation mode. The screening mode is an observation mode that achieves both whiteness and improved visibility. The WLI mode corresponds to a general white light observation mode. The special light observation mode is an NBI (Narrow Band imaging) mode capable of emphasizing surface blood vessels, an AFI (AutoFluorescence Imaging) mode capable of observing fluorescence, and an RDI mode capable of emphasizing deep blood vessels.

An observation mode selection switch is provided at least one of the operation unit 220 of the scope 200, the input unit 600 of the control device 100, and the light source device 160. The user selects the observation mode by operating the observation mode selection switch. The selected observation mode information is transmitted to the light amount ratio control circuit 152. For example, when the input unit 600 is provided with the observation mode selection switch, the observation mode information is transmitted from the input unit 600 to the light amount ratio control circuit 152 via the processing circuit 110.

The light amount ratio control circuit 152 reads out the light amount ratio set value corresponding to the selected observation mode from the light amount ratio storage unit 151, and controls the light amount ratio according to the light amount ratio set value. Specifically, when the screening mode is selected, the light amount ratio control circuit 152 controls the light amount ratio according to the first normal light observation set value. When the WLI mode is selected, the light amount ratio control circuit 152 controls the light amount ratio according to the second normal light observation set value. Even when the special light observation mode is selected, the light amount ratio setting value corresponding to each mode is used.

The light amount ratio storage unit 151 stores the light amount ratio in each observation mode and the type of LED to emit light as a light amount ratio set value. In other words, depending on the observation mode, all five LEDs may be made to emit light, or only some LEDs may be made to emit light. Further, the image processing or the like may be changed according to the observation mode. It is also preferable that the image processing circuit (not shown) selects and processes the corresponding image processing based on the information of the selected observation mode. The light source controller 150 may have a dimming function that adjusts the amount of light of each light source according to the brightness of an image or the like. Dimming is a function of adjusting the amount of light of a light source so that the image becomes appropriate brightness according to a situation such as a change in the distance between the tip of the scope and the subject or the reflectance of the subject. The light source controller 150 performs dimming by increasing or decreasing the amount of light of the entire illumination light while maintaining the ratio of the amount of light of the five light sources.

The details of each observation mode will be explained. First, a WLI mode corresponding to a general normal light observation mode will be described.

In the WLI mode, the illumination light is white light. When the WLI mode is selected, the light source controller 150 causes the five light sources LDV, LDB, LDG, LDA, and LDR to emit light based on the second normal light observation set value. The light intensity ratio is set so that an image substantially equal to an image obtained by a conventional endoscopic light source such as a xenon lamp can be obtained. That is, when the light amounts of the light sources LDV, LDB, LDG, LDA, and LDR are Vp, Bp, Gp, Ap, and Rp, respectively, (Vp + Bp): Gp: (Ap + Rp) ≈ 1: 1: 1. For example, the ratios of (Vp + Bp), Gp, and (Ap + Rp) are 0.9 or more and 1.1 or less, respectively. However, the white condition is not limited to this, and may be a range of a ratio that can be adjusted to white by adjusting image processing, a display device, or the like. Further, Vp: Bp and Ap: Rp are set so that the tint of the acquired image is substantially equal to that of the conventional white light observation image. That is, it is set based on the color expression in white light observation. The light intensity ratios Vp / Bp and Ap / Rp based on the color representation are both smaller than 1. More preferably, Vp / Bp and Ap / Rp are both 0.5 or more and 0.9 or less. For example, when Vp / Bp and Ap / Rp are 0.5, respectively, Vp: Bp: Gp: Ap: Rp≈0.33: 0.66: 1.0: 0.33: 0.66.

The special light observation mode is a mode for observing with illumination light having a special spectral pattern according to the observation purpose, as represented by the NBI mode and the like. For example, NBI is an observation mode in which the visibility of blood vessels in the surface layer to the middle layer is improved by using bluish-purple light in the vicinity of 415 nm and green light in the vicinity of 540 nm.

The basic operation when the special light observation mode is selected as the observation mode is almost the same as that in the WLI mode.

The endoscope device in this embodiment can be selected from a plurality of special light observation modes such as NBI, AFI, and RDI, and can be selected according to the purpose.

The NBI mode is an observation mode for improving the visibility of lesions such as cancer, and lights the light sources LDV and LDG. The AFI mode is a mode for observing autofluorescence, and lights the light sources LDV and LDG. The light sources that light up in NBI mode and AFI mode are the same, but the light intensity ratios are different from each other. Moreover, since the optimum spectral shape is also different, the NBI and AFI spectra are different depending on the observation mode compatible filter. That is, the spectra of NBI and AFI are adjusted so as to be optimal for NBI observation and AFI observation, respectively. The observation mode compatible filter is inserted in the optical path.

The RDI mode is an observation mode that improves the visibility of deep blood vessels or bleeding points, and lights the light sources LDB, LDA, and LDR. In addition, the observation mode compatible filter inserts an RDI object into the optical path.

The light amount ratio in the special light observation mode is set based on the target function of each observation mode, for example, the degree of improvement in the visibility of the feature portion. Similarly, the color representation of the special light observation mode is also set based on the target function of the observation mode, and is generally different from the color representation of the normal light observation image. ..

The case where the screening mode is selected as the observation mode will be described.

The screening mode is an observation mode for the purpose of observation for finding lesions, so-called screening, mainly in situations such as health examinations. Therefore, the visibility of the lesion or the like is higher than that of the WLI mode, and the color expression is more natural than that of the special light mode. As a result, it is possible to prevent the lesion from being overlooked and to realize a natural color to observe without discomfort. The purpose of general special light is to make it easier to judge the visibility of the lesion and the condition of the lesion, and the color tone is set to be optimal for the purpose, so the appearance is different from white light. .. For this reason, some doctors may feel tired easily. By achieving both color and visibility, it is possible to realize screening that is less likely to cause fatigue even during long hours of work like white light and is less likely to be overlooked like special light.

In the screening mode, the five color light sources LDV, LDB, LDG, LDA, and LDR are made to emit light based on the set values for the first normal light observation. The light intensity ratio of the five color light sources is set to be (Vp + Bp): Gp: (Ap + Rp) ≈ 1: 1: 1. With such a configuration, it becomes a natural illumination light, and there is a possibility that the discomfort and fatigue of the operator can be reduced.

Vp / Bp and Ap / Rp are set to improve the visibility of lesions and the like. In this embodiment, as in the NBI mode or the RDI mode, the setting is based on the spectral characteristics of hemoglobin, which is a common characteristic substance in the field of medical endoscopy. Both Vp / Bp and Ap / Rp are larger than 1 and 3 or less. More preferably, Vp / Bp and Ap / Rp are both 1.2 or more and 2.2 or less. These values were determined based on experiments in which vascular contrast was observed while changing the light intensity ratio. For example, when both Vp / Bp and Ap / Rp are 2.0, Vp: Bp: Gp: Ap: Rp≈0.66: 0.33: 1.0: 0.66: 0.33.

The method of setting the light intensity ratio in the WLI mode and the screening mode will be described in detail. First, the WLI mode will be described.

In the WLI mode, the light intensity ratio is set so that the color of the illumination light is natural white light and the color expression is equivalent to that of the conventionally used xenon lamp. As a result of the studies so far, we have found that the larger the Vp / Bp, the stronger the yellowish color, and conversely, the smaller the Vp / Bp, the stronger the bluish color. It was also found that when Ap / Rp increased, the redness became lighter and slightly brownish, and when Ap / Rp decreased, the redness became darker. It has been confirmed that by setting Vp / Bp and Ap / Rp in the range of about 0.5 or more and 0.9 or less, respectively, it is possible to realize a color expression equivalent to that of a xenon lamp. However, the detailed ratio needs to be set according to the peak wavelength and the spectrum pattern of each LED. Further, in the case of the light amount ratio set in this way, the light amount Vp of the light source LDV that relatively improves the visibility is smaller than the light amount Bp of the light source LDB that does not relatively improve the visibility, so that the visibility improvement level is high. Not expensive compared to special light observation mode. The relationship between Ap and Rp is similar.

In the screening mode, the purpose of lighting is to achieve both white light and improved visibility.

Specifically, (Vp + Bp): Gp: (Ap + Rp) ≈ 1: 1: 1 is set. In addition, the visibility of the region of interest can be improved by increasing (the amount of light belonging to the visibility improving region) / (the amount of light belonging to the non-visibility improving region) in each color region as compared with the WLI mode. .. Specifically, Vp / Bp and Ap / Rp are each set to a value larger than 1.

Replacing the above condition with the light intensity ratio of 5 light sources, Vp: Bp: Gp: Ap: Rp≈0.5 + α: 0.5-α: 1.0: 0.5 + β: 0.5-β. α and β are real numbers, and α ≧ 0 and β ≧ 0. By setting this light amount ratio as the first normal light observation setting value, it is possible to realize illumination close to white with improved visibility.

In the screening mode, it is necessary to set the color expression to a level close to that of the WLI mode so that workers such as doctors can perform screening without discomfort. In other words, when Vp / Bp is too large, or when Ap / Rp is too large, the color expression changes, and the operator may feel uncomfortable during screening. For example, when Vp / Bp exceeds 3, the yellowness of the image becomes too strong. When Ap / Rp exceeds 3, the redness becomes lighter and the brownishness becomes stronger. In addition, as a result of the examination, it was found that if Vp / Bp and Ap / Rp are less than 3, a color expression that does not cause a sense of discomfort can be realized, and if it is 2.2 or less, screening is possible with almost no discomfort. It was.

The above three conditions can be summarized as follows.

First condition: Must be white. That is, (Vp + Bp): Gp: (Ap + Rp) ≈ 1: 1: 1.

Second condition: It has the effect of improving visibility. That is, Vp / Bp and Ap / Rp are both 0.9 or more. In order to be more effective, it is desirable that both Vp / Bp and Ap / Rp are 1.0 or more.

Third condition: There should be no discomfort in color expression. That is, both Vp / Bp and Ap / Rp are less than 3.0. In order to realize a more comfortable image, it is desirable that Vp / Bp and Ap / Rp are both 2.2 or less.

Replacing the first to third conditions with the light intensity ratio of the five light sources, Vp: Bp: Gp: Ap: Rp≈0.47 + γ: 0.53-γ: 1.0: 0.47 + δ: 0.53-δ Is. γ and δ are real numbers, and 0 <γ <0.3 and 0 <δ <0.3.

More preferably, Vp: Bp: Gp: Ap: Rp≈0.5 + η: 0.5-η: 1.0: 0.5 + ζ: 0.5-ζ. η and ζ are real numbers, and 0 ≦ η ≦ 0.19 and 0 ≦ ζ ≦ 0.19.

In the present embodiment, the light source LDG that emits green light is a hybrid light source that combines a blue LED and a phosphor. For this reason, it has a spectral shape with a wide hem on the long wavelength side, but it is desirable to cut the portion protruding into the amber region from the viewpoint of light amount ratio control. For example, the dichroic filter DC3 may be provided with a function of cutting the light emitted from the light source LDG that protrudes into the amber region.

Note that the wavelength region of the emitted light of each light source may be limited according to the observation mode. In this case, an observation mode-compatible filter is inserted on the optical path according to the selected observation mode. The observation mode compatible filter may be a filter used in a conventional endoscope. In FIG. 6, it is preferable to insert an observation mode-compatible filter after the optical combine section 141 has combined and before the light guide 214 is incident. Although not shown in this embodiment, when the observation mode is selected, the observation mode compatible filter mounted on the rotating disk (turret) is inserted on the optical path.

According to the embodiment described above, the light amount ratio setting value sets the first light amount ratio corresponding to the white illumination light and the second light amount ratio in which the light amount of the first light source is larger than the light amount of the second light source. It is a value to be used.

By doing so, the light source controller 150 sets the light amount ratio of the illumination light based on the light amount ratio set value, so that the illumination light that realizes the first light amount ratio and the second light amount ratio can be generated.

In the first embodiment, the light amount ratio set value is the light amount ratio set value in the screening mode. The first light amount ratio is a light amount ratio that satisfies the white light requirement, and the second light amount ratio is a light amount ratio that satisfies the visibility improvement requirement. In the first embodiment, the second light intensity ratio may be either Vp / Bp or Ap / Rp.

Further, in the present embodiment, (the amount of light of the first light source) / (the amount of light of the second light source) set as the second light amount ratio is 1.5 or more and 2.2 or less.

By doing so, the amount of light of the first light source having a large degree of emphasis in the area of interest can be made larger than the amount of light of the second light source having a small degree of emphasis in the area of interest, so that the visibility of the area of interest can be improved. Further, by setting the ratio to 1.5 or more and 2.2 or less, it is possible to maintain the naturalness of white light and improve the visibility of the region of interest.

In the first embodiment, the first light source and the second light source are the light source LDV and the light source LDB, or the light source LDA and the light source LDR.

Further, in the present embodiment, the four or more light sources emit a purple light source LDV that emits purple light IV, a blue light source LDB that emits blue light IB, a green light source LDG that emits green light IG, and amber light IA. The amber light source LDA and the red light source LDR that emits red light IR are included. Let the light amounts of the purple light source LDV, the blue light source LDB, the green light source LDG, the amber light source LDA, and the red light source LDR be Vp, Bp, Gp, Ap, and Rp, respectively. At this time, (Vp + Bp): Gp :( Ap + Rp) set as the first light amount ratio is a light amount ratio that turns white. Moreover, Vp / Bp and Ap / Rp set as the second light amount ratio are both larger than 1.

In this way, it is possible to achieve both the white light requirement and the visibility improvement requirement in the illumination light of the five light sources. From the relationship between the visibility improvement region and each color region in the hemoglobin absorption spectrum, it is considered that the red region and the blue region greatly contribute to the visibility improvement. In the present embodiment, visibility can be improved by setting both Vp / Bp and Ap / Rp to be larger than 1. On the other hand, since the green region has a large effect on the brightness in the visual sense, it is possible to obtain illumination light closer to white light by setting the green light IG to a broad spectrum.

Further, in the present embodiment, Vp / Bp and Ap / Rp set as the second light intensity ratio are both 1.5 or more and 2.2 or less.

By doing so, in the blue region and the red region, it is possible to maintain the naturalness as white light and improve the visibility of the region of interest. For example, in the gastrointestinal mucosa, the visibility of surface blood vessels and deep blood vessels can be improved, and the naturalness of white light can be maintained.

Further, in the present embodiment, when the first normal light observation mode is set, the light source controller 150 sets the light amount ratio set value to the first normal light observation set value, and when the second normal light observation mode is set. The light amount ratio set value is set to the second normal light observation set value. In the first normal light observation set value and the second normal light observation set value, (Vp + Bp): Gp :( Ap + Rp) is a light amount ratio that makes white. In the first normal light observation set value, both Vp / Bp and Ap / Rp are larger than 1. In the second normal light observation set value, both Vp / Bp and Ap / Rp are smaller than 1.

By doing so, it is possible to provide the user with a first normal light observation mode that achieves both whiteness and improved visibility, and a second normal light observation mode that realizes more natural white light.

In the first embodiment, the first normal light observation mode is the screening mode, and the second normal light observation mode is the WLI mode. However, the application of the first normal light observation mode is not limited to screening. That is, the first normal light observation mode can be used even in a medical examination or surgery where it is necessary to improve the visibility of the region of interest while ensuring the natural color of white light.

Further, in the present embodiment, the degree of emphasis of the region of interest is higher in the first normal light observation mode than in the second normal light observation mode.

That is, when both Vp / Bp and Ap / Rp are larger than 1 in the first normal light observation set value, the degree of emphasis of the region of interest becomes relatively large in the first normal light observation mode. On the other hand, since Vp / Bp and Ap / Rp are both smaller than 1 in the second normal light observation set value, the degree of emphasis of the region of interest is relatively small in the second normal light observation mode.

Further, in the present embodiment, the light source controller 150 sets the light amount ratio set value to the normal light observation set value when the normal light observation mode is set, and sets the light amount ratio set value to the special light amount ratio set value when the special light observation mode is set. Set to the light observation setting value. The ratio of the amount of blue light, the amount of green light, and the amount of red light in the set value for normal light observation is relatively closer to 1: 1: 1 than the ratio of the amount of blue light, the amount of green light, and the amount of red light in the set value for special light observation.

Since the special light observation mode is a mode that prioritizes the visibility of the area of interest, the image may have a color balance different from that of white light in general. Therefore, the amount of blue light: the amount of green light: the amount of red light may be relatively farther than 1: 1: 1 as compared with the normal light observation mode. For example, in the normal light observation mode, each ratio of the amount of blue light, the amount of green light, and the amount of red light is in the range of 0.9 or more and 1.1 or less. On the other hand, in the special light observation mode, the ratio of one or more of the blue light amount, the green light amount and the red light amount is less than 0.9 or larger than 1.1.

In the first embodiment, the normal light observation mode is a screening mode or a WLI mode. The special light observation mode is an NBI mode, an AFI mode, or an RDI mode.

Further, in the present embodiment, the light source unit 140 includes the first to nth light sources as four or more light sources. n is an integer of 4 or more. When the first normal light observation mode is set, the light source controller 150 sets the light amount ratio set value to the first normal light observation set value and causes the first to nth light sources to emit light. When the second normal light observation mode is set, the light source controller 150 sets the light amount ratio set value to the second normal light observation set value and causes the first to nth light sources to emit light. When the special light observation mode is set, the light source controller 150 sets the light amount ratio set value to the special light observation set value, and emits a plurality of light sources corresponding to the special light among the first to nth light sources. In the first normal light observation set value and the second normal light observation set value, the ratio of the blue light amount, the green light amount, and the red light amount is the white light amount ratio. The light intensity ratios of the plurality of light sources in the first normal light observation set value are relatively plurality in the special light observation set value as compared with the light intensity ratios of the plurality of light sources in the second normal light observation set value. It is close to the light intensity ratio of the light source.

For example, when the special light observation mode is the NBI mode, the light source controller 150 causes the purple light source LDV and the green light source LDG to emit light. Since Vp / Bp> 1 in the screening mode (first normal light observation mode) and Vp / Bp <1 in the WLI mode (second normal light observation mode), Vp / Gp in the screening mode is WLI. It becomes larger than Vp / Gp in the mode. Considering that Vp / Gp> 1 in the NBI mode, it can be said that Vp / Gp in the screening mode is relatively close to Vp / Gp in the special light mode as compared with Vp / Gp in the WLI mode. The same applies to the AFI mode and the RDI mode.

Further, in the present embodiment, the light source controller 150 includes a light amount ratio storage unit 151 and a light amount ratio control circuit 152. The light amount ratio storage unit 151 stores a plurality of light amount ratio set values corresponding to the plurality of observation modes. The light amount ratio control circuit 152 reads out the light amount ratio set value corresponding to the set observation mode among the plurality of observation modes from the light amount ratio storage unit 151, and based on the read-out light amount ratio set value, the light amount of four or more light sources. Control the ratio.

In this way, the illumination light can be switched according to the observation mode selected by the user. For example, the illumination light in the WLI mode, which is close to the conventional white light such as a xenon lamp, the illumination light in the screening mode that achieves both the white light requirement and the visibility improvement requirement, and the illumination light in the special light observation mode such as NBI are switched. be able to.

Further, in the present embodiment, the light source controller 150 synchronizes the light amounts of four or more light sources based on the light amount ratio set value even when the light amount of the illumination light changes, so that the first light amount ratio and the second light amount are synchronized. Maintain the ratio.

For example, the amount of illumination light changes by dimming control as described above. At this time, the light source controller 150 can maintain the first light amount ratio and the second light amount ratio by synchronously changing the light amounts of four or more light sources based on the light amount ratio set value. As a result, the amount of illumination light can be changed while maintaining both the white light requirement and the visibility improvement requirement.

Further, in the present embodiment, as shown in FIG. 4, a visibility improving region that relatively improves visibility and a non-visibility improving region that does not relatively improve visibility based on the spectral spectrum of the observation object It is divided into and. As shown in FIGS. 5 and 7, one of the two lights belonging to the same color region belongs to the visibility improving region, and the other belongs to the non-visibility improving region.

Further, in the present embodiment, as shown in FIGS. 5 and 7, the visible light wavelength region is divided into a blue region, a green region, and a red region. The visible light wavelength region is divided into four or more wavelength regions based on the three color regions, the visibility improving region, and the non-visibility improving region. At this time, the peak wavelengths of the four or more light sources belong to different wavelength regions. In the example of FIG. 5, the visible light wavelength region is divided into six wavelength regions of RA to RF. The peak wavelengths of the five optical IVs, IBs, IGs, IAs, and IRs belong to different wavelength regions RA, RB, RD, RE, and RF.

Also, in this embodiment, the object to be observed is hemoglobin. At this time, the four or more light sources are the five wavelength light sources LDV, LDB, LDG, LDA, and LDR. The peak wavelengths of the light IV, IG, and IA emitted by the light sources LDV, LDG, and LDA belong to the visibility improvement region, and the peak wavelengths of the light IB and IR emitted by the light sources LDB and LDR belong to the invisibility improvement region.

Further, in the present embodiment, the first light intensity ratio (Vp + Bp): Gp :( Ap + Rp) is set based on the color balance. The second light intensity ratios, Vp: Bp and Ap: Rp, are set based on the relative visibility improvement level.

Further, in the present embodiment, the endoscope device has a plurality of observation modes, and the light amount ratio of each observation mode is set based on the color balance and the visibility of the region of interest.

Further, in the present embodiment, the endoscope device has a WLI mode and a screening mode. The light intensity ratio of the light whose peak wavelength belongs to the visibility improving region in the screening mode is relatively higher than the light intensity ratio of the light in the WLI mode.

Further, in the present embodiment, the first light amount ratio and the second light amount ratio may be set in consideration of the spectral sensitivity characteristic of the image sensor and the spectral characteristic of the optical member on the optical path. The spectral sensitivity characteristics of the image sensor are the element sensitivity and the color filter spectral characteristics. The optical members are an optical combine unit 141, a light guide 214, and

illumination lenses

211 and 212.

5. Second Embodiment Hereinafter, the second embodiment will be described, but the description of the parts common to the first embodiment will be omitted.

In the second embodiment, the light source device 160 has a blue-green region cut filter. The blue-green region cut filter cuts the green light emitted by the light source LDG, which is approximately 510 nm or less.

As shown in FIG. 5, of the green region, 495 nm to 510 nm is a non-visibility improvement region RC that does not relatively improve visibility. Therefore, from the viewpoint of improving visibility, it is preferable that there is no light component in the non-visibility improving region RC. On the other hand, the target subject of the medical endoscope is the mucous membrane of the stomach, esophagus, large intestine, etc., and the light in the non-visibility improving region RC is generally absorbed. Therefore, the influence on the color expression is limited.

Therefore, in the second embodiment, a blue-green region cut filter is newly provided for the purpose of cutting the light in the non-visibility improvement region RC. The non-visibility improvement region RC corresponds to a blue-green region.

In FIG. 6, a blue-green region cut filter is inserted after the optical combine section 141 is combined and before the light guide 214 is incident. The rotating disk is provided with a plurality of openings, one of which is equipped with a turquoise region cut filter, and the turquoise region cut filter is inserted into the optical path when the screening mode is selected.

FIG. 8 is an example of the wavelength characteristics of the blue-green region cut filter. FIG. 9 is an example of the spectrum of the illumination light when the blue-green region cut filter is inserted into the optical path.

As shown in FIGS. 8 and 9, the blue-green region cut filter cuts light of 495 nm to 510 nm and transmits light of other wavelengths. As shown in FIG. 8, the blue-green region cut filter may have a transmittance of about 0.1 at 495 nm to 510 nm. Thereby, it is also possible to restore the color information in the range of 495 nm to 510 nm by image processing.

According to the second embodiment, since the light in the region where the visibility is not relatively improved in the green region can be reduced, the visibility of the blood vessels in the middle layer can be further improved as compared with the first embodiment.

The second embodiment can be modified as follows. In the second embodiment, the filter is inserted between the optical combine section 141 and the incident end of the light guide 214, but in the modified example, the wavelength characteristic of the dichroic filter DC2 is changed.

FIG. 10 is an example of the transmittance characteristics of the dichroic filter DC2 in the first embodiment and the second embodiment. FIG. 11 is an example of the wavelength characteristics of the dichroic filter DC2 in the modified example of the second embodiment.

In FIG. 10, the half-value wavelength is 495 nm in the transmittance characteristics of the dichroic filter DC2. The half-value wavelength is a wavelength at which the reflectance and transmittance are 50%. On the other hand, in FIG. 11, the half-value wavelength is 510 nm.

With the configuration as shown in FIG. 11, of the green light emitted from the light source LDG, the light in the range of 495 nm to 510 nm is transmitted without being reflected, and is not guided in the incident end direction of the light guide 214. As a result, the illumination light incident on the incident end of the light guide 214 has the spectrum shown in FIG.

According to this modification, it is not necessary to separately provide a blue-green region cut filter for the screening mode, so that a simple configuration can be realized at a lower cost.

In the first embodiment and the second embodiment, there are wavelength components of 495 nm to 510 nm in the WLI mode, and the wavelength components of 495 nm to 510 nm are cut only in the screening mode. On the other hand, in this modification, the wavelength component of 495 nm to 510 nm is cut even in the WLI mode. However, as described above, since the subject of the medical endoscope absorbs light in this region, the influence on the image is limited. Therefore, the configuration of this modification is effective when the cost and size are prioritized. ..

The dichroic filters DC1 to DC4 all have a high transmittance on the short wavelength side of about 100% and a low transmittance on the long wavelength side of about 0%. The dichroic filters DC1 to DC4 are filters using a dielectric multilayer mirror. Since it is a dielectric multilayer mirror, almost all light that does not pass through is reflected. That is, the value obtained by subtracting the transmittance from 100% is the substantially reflectance. In addition, it is desirable to design the change in the transmittance of each filter to be as steep as possible. However, it is also preferable to set an appropriate inclination in consideration of cost and the like.

According to the above embodiment, the third wavelength region and the fourth wavelength region belong to the second same color region different from the first same color region among the blue region, the green region and the red region. In the second same color region, it is assumed that the light absorption spectrum of the observation object in the third wavelength region is relatively larger than the light absorption spectrum of the observation object in the fourth wavelength region. At this time, the four or more light sources include a third light source that emits light having a peak wavelength in the third wavelength region and a fourth light source that emits light having a peak wavelength in the fourth wavelength region. Alternatively, the third light source is included and the fourth light source is not included.

In the second embodiment, the first identical color region is a blue region or a red region, and the second identical color region is a green region. At this time, the third wavelength region is the RD of FIG. 5, and the fourth wavelength region is the RC of FIG. In the second embodiment, the light source unit 140 includes a green light source which is a third light source, but does not include a fourth light source. The case where the light source unit 140 includes the third light source and the fourth light source will be described in the third embodiment.

Further, in the present embodiment, when four or more light sources include the third light source and do not include the fourth light source, the tail of the spectrum of the light emitted by the third light source overlaps the fourth wavelength region.

That is, as shown in FIG. 7, the spectrum of the green light IG emitted by the third light source has a skirt on the short wavelength side, and the skirt overlaps with RC which is the fourth wavelength region.

Further, in the present embodiment, the light source unit 140 has an optical filter that is arranged on the optical path of the illumination light and reduces the light in the fourth wavelength region.

As a result, the light in the fourth wavelength region, in which the absorption spectrum of hemoglobin is relatively small, that is, the visibility is not relatively improved, can be reduced by the optical filter. By reducing the light in the fourth wavelength region that does not relatively improve the visibility, the visibility improving effect can be enhanced. In the second embodiment, the blue-green region cut filter corresponds to the optical filter.

6. Third Embodiment Hereinafter, the third embodiment will be described, but the description of the parts common to the first embodiment will be omitted.

In the first embodiment and the second embodiment, one light source LDG emits light in the green region, but in the third embodiment, the two blue-green light sources and the yellow-green light source emit light in the green region. The blue-green light source and the yellow-green light source are, for example, LEDs that do not use a phosphor. The blue-green light emitted by the blue-green light source has a peak wavelength of 505 nm, and the yellow-green light emitted by the yellow-green light source has a peak wavelength of 550 nm.

The spectrum of the illumination light in the third embodiment is as shown in FIG. 3 described above. In FIG. 3, the light IG1 is a blue-green light and the light IG2 is a yellow-green light. The spectrum of the optical IG1 is distributed in the wavelength region RC in FIG. That is, the optical IG1 is light that does not relatively improve visibility. The spectrum of the optical IG2 is distributed in the wavelength region RD in FIG. That is, the optical IG2 is light that relatively improves visibility.

The light emission control in each observation mode is basically the same as in the first and second embodiments.

In the WLI mode, the light source controller 150 lights the light sources of all six colors. Further, the light source controller 150 sets the first light intensity ratio to (Vp + Bp) :( G1p + G2p) :( Ap + Rp) ≈ 1: 1: 1. G1p is the amount of blue-green light, and G2p is the amount of yellow-green light.

The second light intensity ratio, G2p / G1p, is set based on the tint. In the WLI mode, G2p / G1p is preferably about 1.5 or more and less than 2.2.

In the special light mode NBI mode and AFI mode, the purple light IV and the yellow-green light IG2 are turned on. Turn off the blue light IB, the blue-green light IG1, the amber light IA, and the red light IR.

In the screening mode, the illumination light is configured as follows in order to satisfy the first to third conditions described in the first embodiment.

First condition: It must be white. That is, (Vp + Bp) :( G1p + G2p) :( Ap + Rp) ≈ 1: 1: 1. For example, the ratio of each of (Vp + Bp), (G1p + G2p), and (Ap + Rp) is 0.9 or more and 1.1 or less. However, the white condition is not limited to this, and may be a range of a ratio that can be adjusted to white by adjusting image processing, a display device, or the like.

Second condition: It has the effect of improving visibility. That is, Vp / Bp, G2p / G1p, and Ap / Rp are all 0.9 or more. In order to be more effective, it is desirable that Vp / Bp, G2p / G1p, and Ap / Rp are all 1.0 or more.

Third condition: There should be no discomfort in color expression. That is, Vp / Bp, G2p / G1p, and Ap / Rp are all less than 3.0. In order to realize a more natural image, it is desirable that Vp / Bp, G2p / G1p, and Ap / Rp are all 2.2 or less.

Replacing the first to third conditions with the light intensity ratio of the six light sources, Vp: Bp: G1p: G2p: Ap: Rp≈0.47 + φ: 0.53-φ: 0.53-ε: 0.47 + ε: 0 .47 + ξ: 0.53-ξ. φ, ε, and ξ are real numbers, and 0 <φ <0.3, 0 <ε <0.3, and 0 <ξ <0.3.

More preferably, Vp: Bp: G1p: G2p: Ap: Rp≈0.47 + κ: 0.53-κ: 0.53-μ: 0.47 + μ: 0.47 + ν: 0.53-ν. κ, μ, and ν are real numbers, and 0 ≦ κ ≦ 0.19, 0 ≦ μ ≦ 0.19, and 0 <ν ≦ 0.19.

According to the third embodiment, it is possible to realize the illumination light of the screening mode with further improved visibility as compared with the first embodiment. Further, as compared with the second embodiment, it is possible to realize the illumination light of the screening mode with further improved visibility without using the blue-green region cut filter for the screening mode. Further, as compared with the modified example of the second embodiment, it is possible to realize the illumination light of the screening mode in which the visibility is further improved without affecting the WLI mode.

The screening mode does not have to be a single mode. A plurality of screening modes having different light intensity ratios may be provided within a range satisfying the first to third conditions. Further, a screening mode may be provided in which the visibility improvement level can be adjusted stepwise or steplessly. At this time, in all the color regions, the light amount ratio of the visibility improving region and the non-visibility improving region may be increased or decreased in conjunction with each other. Further, the light amount ratio between the visibility improving region and the non-visibility improving region may be controlled independently for each color region. As a result, the visibility improvement level can be independently adjusted in each of the surface layer, the middle layer, and the deep layer in the living body. When a plurality of screening modes are prepared, the visibility may be changed in order according to the visibility improvement level. For example, the visibility may be adjusted so that the visibility changes in order with the visibility up / down buttons and the like.

Further, the object to be observed is not limited to hemoglobin, and may be various drugs. By selecting the wavelength and light intensity ratio of the LED according to the spectral spectra of various chemicals, the distribution of fluorescent chemicals can be confirmed with good visibility. Examples of the drug will be described later.

Further, the illumination light is not limited to the visible light wavelength region, and may be extended to near infrared or near ultraviolet. For example, when a fluorescent agent that emits light in the near infrared is used, the wavelength region of the illumination light may be extended to the near infrared.

Further, the screening mode may also be used as the WLI mode. In this case, it is not necessary to provide the normal light observation mode.

In addition, various modifications are possible without departing from the gist of the present invention.

According to the above embodiment, the four or more light sources included in the light source device 160 include a purple light source LDV that emits purple light IV, a blue light source LDB that emits blue light IB, and a first green light. Includes a 1-green light source, a second green light source that emits a second green light having a wavelength longer than that of the first green light, an amber light source LDA that emits amber light IA, and a red light source LDR that emits red light IR. .. The light amounts of the purple light source LDV, the blue light source LDB, the first green light source, the second green light source, the amber light source LDA, and the red light source LDR are Vp, Bp, G1p, G2p, Ap, and Rp, respectively. At this time, (Vp + Bp) :( G1p + G2p) :( Ap + Rp) set as the first light amount ratio is a light amount ratio that turns white. Moreover, Vp / Bp, G2p / G1p and Ap / Rp set as the second light amount ratio are all larger than 1.

By doing so, it is possible to achieve both the white light requirement and the visibility improvement requirement in the illumination light of the six light sources. Compared with the illumination light of the five light sources, the visibility of the region of interest can be further improved even in the green region. For example, in the gastrointestinal mucosa, the visibility of surface blood vessels, middle blood vessels, and deep blood vessels can be improved, and the naturalness of white light can be maintained.

In the third embodiment, the first green light is a blue-green light, the first green light source is a blue-green light source, the second green light is a yellow-green light, and the second green light source is a yellow-green light source. ..

Further, in the present embodiment, when the light source controller 150 is set to any of a plurality of normal light observation modes in which the degree of emphasis of the region of interest is stepwise or continuously different, the light source controller 150 corresponds to the set observation mode. Set the light amount ratio setting value of the light amount ratio.

That is, the light source controller 150 changes the degree of emphasis of the region of interest stepwise or continuously by gradually or continuously changing the light amount ratio setting value of the second light amount ratio according to the mode selection. In this way, the degree of visibility improvement can be adjusted according to the needs of the user.

7. Drugs Figure 12 is an absorption spectrum of indocyanine green (ICG). Indocyanine green hardly absorbs light in the blue region and the green region, absorbs rapidly from around 600 nm of amber, and has an absorption peak near 700 nm. That is, indocyanine green absorbs more in the red band than in the amber band.

In FIG. 12, VE is a visibility improving region, and NVD and NVE are non-visibility improving regions. When combined with the color region, it can be divided into the following wavelength regions.
Non-visibility improvement region in the blue region: 400 nm ≤ λ <495 nm
Non-visibility improvement region in the green region: 495 nm ≤ λ <585 nm
Non-visibility improvement region in the red region: 585 nm ≤ λ <620 nm
Visibility improvement region in the red region: 620 nm ≤ λ <680 nm

FIG. 13 is an example of the illumination light spectrum. In FIG. 13, the illumination light is five light sources similar to those in the first embodiment.

According to FIGS. 12 and 13, the light intensity ratio of light IV and IB and the light intensity in the green region do not affect the visibility of indocyanine green. The visibility of indocyanine green is determined by the light intensity ratio in the red region. In the red region, the red light IR is larger than the absorption intensity of the amber light IA. Therefore, the visibility of indocyanine green can be improved by red light IR rather than by amber light IA. That is, the visibility can be improved by the light having a wavelength longer than that of the light having a wavelength shorter than 620 nm.

In the configuration with a five-color light source, the visibility of indocyanine green can be improved by increasing the amount of red light IR as compared with amber light IA. The white light requirement is (Vp + Bp): Gp :( Ap + Rp) ≈ 1: 1: 1 as in the first embodiment. The second light amount ratio Rp / Ap can be arbitrarily set within the range that satisfies this first light amount ratio. For example, it may be set to improve the visibility of living tissues such as mucous membranes. For example, by setting Rp / Ap to be larger than 1 and 3 or less, the visibility of indocyanine green can be improved while maintaining the naturalness of white light.

FIG. 14 is an absorption spectrum of indigo carmine. The absorption intensity of indigo carmine is small in the blue region, increases from around 500 nm, and starts to decrease after peaking at around 630 nm.

In FIG. 14, VF is a visibility improving region, and NVF and NVG are non-visibility improving regions. When combined with the color region, it can be divided into the following wavelength regions.
Non-visibility improvement region in the blue region: 400 nm ≤ λ <495 nm
Non-visibility improvement region in the green region: 495 nm ≤ λ <530 nm
Visibility improvement region in the green region: 530 nm ≤ λ <585 nm
Visibility improvement region in the red region: 585 nm ≤ λ <660 nm
Non-visibility improvement region in the red region: 660 nm ≤ λ <680 nm

FIG. 15 is an example of the illumination light spectrum. In FIG. 15, the illumination light is five light sources similar to those in the first embodiment.

According to FIGS. 14 and 15, purple light IV and blue light IB have almost no effect on improving the visibility of indigo carmine. The green light IG is monochromatic, but has a spectrum having a relatively long wavelength and a large amount of light. Therefore, the wavelength component of the green light IG included in the visibility improving region is larger than the wavelength component of the green light IG included in the non-visibility improving region. Therefore, the green light IG can be expected to have a certain degree of visibility improvement effect. Further, since both the amber light IA and the red light IR are included in the visibility improving region, both have the effect of improving the visibility. The red light IR having a peak at 630 nm, which is the peak of the absorption spectrum, has a greater effect of improving visibility than the amber light IA. However, since the amber light IA is also included in the visibility improving region, the visibility improving effect can be obtained regardless of the ratio of the light amount ratio of Ap: Rp. Therefore, Ap: Rp may be any ratio as long as the white light requirement is satisfied. Ap <Rp is desirable from the viewpoint of improving the visibility of indigo carmine. If Ap: Rp = 1: 2, the effect is sufficient. On the other hand, when giving priority to improving the visibility and color of other observation objects, this ratio can contribute to improving the visibility of indigo carmine, even if it is arbitrary.

FIG. 16 is an absorption spectrum of crystal violet. The absorption spectrum of crystal violet is similar to that of indigo carmine. However, in the absorption spectrum of crystal violet, the maximum wavelength is around 590 nm, which is located on the slightly shorter wavelength side as a whole as compared with the absorption spectrum of indigo carmine. That is, the absorption intensity of crystal violet is small in the blue region, increases from around 500 nm, has a peak at 590 nm, and then decreases sharply.

In FIG. 16, VH is a visibility improving region, and NVH and NVI are non-visibility improving regions. When combined with the color region, it can be divided into the following wavelength regions.
Non-visibility improvement region in the blue region: 400 nm ≤ λ <495 nm
Non-visibility improvement region in the green region: 495 nm ≤ λ <520 nm
Visibility improvement region in the green region: 520 nm ≤ λ <585 nm
Visibility improvement region in the red region: 585 nm ≤ λ <610 nm
Non-visibility improvement region in the red region: 610 nm ≤ λ <680 nm

FIG. 17 is an example of the illumination light spectrum. In FIG. 17, the illumination light is five light sources similar to those in the first embodiment.

According to FIGS. 16 and 17, purple light IV and blue light IB have almost no effect on improving the visibility of crystal violet. The green light IG is monochromatic, but has a spectrum having a relatively long wavelength and a large amount of light. Therefore, the wavelength component of the green light IG included in the visibility improving region is relatively larger than the wavelength component of the green light IG included in the non-visibility improving region. Therefore, a certain degree of visibility improvement effect can be expected by the green light IG. In the red region, the amber light IA has an effect of improving visibility because it is close to the peak of the absorption intensity. On the other hand, since the red light IR is included in the non-visibility improving region, the visibility improving effect is relatively small as compared with the amber light IA.

From the above, the amount of purple light IV, blue light IB, and green light IG can be arbitrarily set within a range that satisfies the white light requirement. For example, it may be set to improve the visibility of living tissues such as mucous membranes and the visibility of blood vessels. On the other hand, the second light amount ratio is set to Ap / Rp> 1 within a range that satisfies the white light requirement. For example, by setting Rp / Ap to be larger than 1 and 3 or less, the visibility of crystal violet can be improved while maintaining the naturalness of white light. Further, by setting it larger than 1.5 and 2.2 or less, the visibility improving effect can be further enhanced.

FIG. 18 is an absorption spectrum of Lugol's solution. The absorption spectrum of the Lugol's solution has a maximum near 450 nm and a minimum near 600 nm.

In FIG. 18, VJ and VK are visibility improving regions, and NVJ is a non-visibility improving region. When combined with the color region, it can be divided into the following wavelength regions.
Visibility improvement region in the blue region: 400 nm ≤ λ <495 nm
Visibility improvement region in the green region: 495 nm ≤ λ <520 nm
Non-visibility improvement region in the green region: 520 nm ≤ λ <585 nm
Non-visibility improvement region in the red region: 585 nm ≤ λ <650 nm
Visibility improvement region in the red region: 650 nm ≤ λ <680 nm

As shown in FIG. 18, in the absorption spectrum of Lugol's solution, there are few regions where absorption is extremely small. Therefore, when Lugol's solution is used as an observation object, the effect of improving visibility by the light amount ratio may be limited as compared with other drugs.

FIG. 19 is an example of the illumination light spectrum. In FIG. 19, the illumination light is five light sources similar to those in the first embodiment.

According to FIGS. 18 and 19, in the blue region, the purple light IV and the blue light IB are included in the visibility improvement region, so that both can contribute to the visibility improvement. Since the blue light IB is slightly closer to the absorption maximum, the visibility improvement effect is greater when Bp> Vp. For example, by setting Vp: Bp = 1: 2, the visibility improving effect can be achieved. On the other hand, since the green light IG, the amber light IA, and the red light IR are all included in the non-visibility improving region, the visibility improving effect is small. However, since the amber light IA is near the minimum (600 nm) of the absorption spectrum, the red light IR far from the minimum has a higher visibility improving effect than the amber light IA. For example, when Ap: Rp = 1: 2, visibility can be relatively improved.

Summarizing the above, it is easy to improve visibility by setting Vp: Bp = 1: 2 and Ap: Rp = 1: 2. However, since the effect may be relatively small, the light intensity ratio may be used to improve the visibility of other mucous membranes and blood vessels and the color reproducibility of the image.

Although the embodiments to which the present invention is applied and the modified examples thereof have been described above, the present invention is not limited to the respective embodiments and the modified examples as they are, and at the embodiment, the gist of the invention is not deviated. The components can be transformed and embodied with. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments and modifications. For example, some components may be deleted from all the components described in each embodiment or modification. Further, the components described in different embodiments and modifications may be combined as appropriate. In this way, various modifications and applications are possible within a range that does not deviate from the gist of the invention. In addition, a term described at least once in the specification or drawing together with a different term having a broader meaning or a synonym may be replaced with the different term at any part of the specification or drawing.

10 Endoscope device, 100 control device, 110 processing circuit, 140 light source unit, 141 light source unit, 150 light source controller, 151 light amount ratio storage unit, 152 light amount ratio control circuit, 160 light source device, 200 scope, 210 insertion unit, 211 Illumination lens, 212 Illumination lens, 213 Imaging unit, 214 Light guide, 215 Image signal line, 220 Operation unit, 230 Connection cable, 240 connector, 300 Display unit, 600 Input unit, BA, BB, BG1, BG2, BR, BV wavelength region, HBA, HBB hemoglobin light absorption spectrum, IA, IB, IG, IR, IV light, LDA, LDB, LDG, LDR, LDV light source, NVA, NVB, NVD, NVE, NVF, NVG, NVH, NVI , NVJ non-visibility improvement area, RA-RF wavelength range, VA, VB, VC, VE, VF, VH, VJ, VK visibility improvement area

Claims

A light source unit that emits light having peak wavelengths different from each other and includes four or more light sources that can independently control the amount of light of each light source and generates illumination light to irradiate an observation object.
A light source controller that controls the amount of light of the four or more light sources based on the light amount ratio setting value that sets the light amount ratio of the four or more light sources.
Including
The light amount ratio setting value is a value for setting a first light amount ratio regarding the color balance of the illumination light and a second light amount ratio regarding the degree of emphasis that the illumination light emphasizes the observation object in the region of interest. ,
The four or more light sources include a first light source that emits light having a peak wavelength in the first wavelength region and a second light source that emits light having a peak wavelength in the second wavelength region.
The first wavelength region and the second wavelength region belong to any one of the blue region, the green region, and the red region, which is the first same color region.
In the first same color region, the absorption intensity of the light absorption spectrum of the observation object in the first wavelength region is relatively larger than the absorption intensity of the light absorption spectrum of the observation object in the second wavelength region.
The first light amount ratio is the amount of blue light which is the amount of illumination light in the blue region, the amount of green light which is the amount of light of the illumination light in the green region, and the amount of red light which is the amount of light of the illumination light in the red region. A light source device for an endoscope characterized by having a light intensity ratio.
In claim 1,
The light amount ratio setting value is a value for setting the first light amount ratio corresponding to the white illumination light and the second light amount ratio in which the light amount of the first light source is larger than the light amount of the second light source. ,
The second light amount ratio is a light amount ratio of the first light source and the second light source determined based on the magnitude relationship in the light absorption spectrum of the observation object.
In claim 2,
A light source device for an endoscope, wherein (the amount of light of the first light source) / (the amount of light of the second light source) set as the second light amount ratio is 1.5 or more and 2.2 or less.
In claim 2,
The four or more light sources are a purple light source that emits purple light, a blue light source that emits blue light, a green light source that emits green light, an amber light source that emits amber light, and a red light source that emits red light. And, including
When the light amounts of the purple light source, the blue light source, the green light source, the amber light source, and the red light source are Vp, Bp, Gp, Ap, and Rp, respectively.
(Vp + Bp): Gp :( Ap + Rp) set as the first light amount ratio is a light amount ratio that turns white, and
A light source device for an endoscope, wherein both Vp / Bp and Ap / Rp set as the second light amount ratio are larger than 1.
In claim 4,
A light source device for an endoscope, wherein Vp / Bp and Ap / Rp set as the second light amount ratio are both 1.5 or more and 2.2 or less.
In claim 4,
The light source controller sets the light amount ratio set value to the first normal light observation set value when the first normal light observation mode is set, and the light amount ratio set value when the second normal light observation mode is set. Is set to the second normal light observation setting value,
In the first normal light observation set value and the second normal light observation set value, (Vp + Bp): Gp :( Ap + Rp) is a light amount ratio that makes white.
In the first normal light observation set value, both Vp / Bp and Ap / Rp are larger than 1.
A light source device for an endoscope, wherein Vp / Bp and Ap / Rp are both smaller than 1 in the second normal light observation set value.
In claim 6,
The first normal light observation mode is a light source device for an endoscope, characterized in that the degree of emphasis of the region of interest is higher than that of the second normal light observation mode.
In claim 2,
The four or more light sources are a purple light source that emits purple light, a blue light source that emits blue light, a first green light source that emits first green light, and a second green light having a wavelength longer than that of the first green light. A second green light source that emits light, an amber light source that emits amber light, and a red light source that emits red light are included.
When the light amounts of the purple light source, the blue light source, the first green light source, the second green light source, the amber light source, and the red light source are Vp, Bp, G1p, G2p, Ap, and Rp, respectively.
(Vp + Bp) :( G1p + G2p) :( Ap + Rp) set as the first light amount ratio is a light amount ratio that turns white, and
A light source device for an endoscope, wherein Vp / Bp, G2p / G1p, and Ap / Rp, which are set as the second light amount ratio, are all larger than 1.
In claim 1,
The light source controller sets the light amount ratio setting value to the normal light observation setting value when the normal light observation mode is set, and sets the light amount ratio setting value to the special light observation setting value when the special light observation mode is set. Set to a value
The ratio of the blue light amount, the green light amount, and the red light amount in the normal light observation set value is relatively 1 than the ratio of the blue light amount, the green light amount, and the red light amount in the special light observation set value. A light source device for an endoscope characterized by being close to 1: 1.
In claim 1,
The light source unit includes first to nth light sources (n is an integer of 4 or more) as the 4 or more light sources.
When the first normal light observation mode is set, the light source controller sets the light amount ratio set value to the first normal light observation set value, causes the first to nth light sources to emit light, and observes the second normal light. When the mode is set, the light amount ratio setting value is set to the second normal light observation setting value to cause the first to nth light sources to emit light, and when the special light observation mode is set, the light amount ratio setting value is set. In addition to setting the set value for observing special light, a plurality of light sources corresponding to the special light among the first to nth light sources are made to emit light.
In the first normal light observation set value and the second normal light observation set value, the ratio of the blue light amount, the green light amount, and the red light amount is the white light amount ratio.
The light amount ratio of the plurality of light sources in the first normal light observation set value is a set value for special light observation relative to the light amount ratio of the plurality of light sources in the second normal light observation set value. A light source device for an endoscope, which is characterized by being close to the light intensity ratio of a plurality of light sources in the above.
In claim 1,
When any of a plurality of normal light observation modes having different degrees of emphasis stepwise or continuously is set, the light source controller sets the light amount ratio of the second light amount ratio corresponding to the set observation mode. A light source device for an endoscope, characterized in that a value is set.
In claim 1,
The light source controller
A light amount ratio storage unit that stores a plurality of the light amount ratio set values corresponding to a plurality of observation modes, and a light amount ratio storage unit.
The light amount ratio set value corresponding to the set observation mode among the plurality of observation modes is read out from the light amount ratio storage unit, and the light amount ratio of the four or more light sources is controlled based on the read out light amount ratio set value. Light intensity ratio control circuit and
A light source device for an endoscope, which comprises.
In claim 12,
The light source controller
Even when the amount of illumination light changes, the first light amount ratio and the second light amount ratio can be maintained by synchronizing the light amounts of the four or more light sources based on the light amount ratio set value. A featured light source device for endoscopes.
In claim 1,
The third wavelength region and the fourth wavelength region belong to the second same color region different from the first same color region among the blue region, the green region, and the red region, and in the second same color region, the said When the light absorption spectrum of the observation object in the third wavelength region is relatively larger than the light absorption spectrum of the observation object in the fourth wavelength region.
The four or more light sources are
A third light source that emits light having a peak wavelength in the third wavelength region and a fourth light source that emits light having a peak wavelength in the fourth wavelength region are included.
Alternatively, an endoscope light source device including the third light source and not including the fourth light source.
In claim 14,
When the four or more light sources include the third light source and do not include the fourth light source.
A light source device for an endoscope, wherein the skirt of a spectrum of light emitted by the third light source overlaps the fourth wavelength region.
In claim 14,
The light source unit
A light source device for an endoscope, which is arranged on an optical path of the illumination light and has an optical filter that reduces light in the fourth wavelength region.
In claim 1,
The observation object is a light source device for an endoscope, which is a substance or a drug contained in a living body.
In claim 1,
The object to be observed is a light source device for an endoscope, which is at least one of hemoglobin, indocyanine green, indigo carmine, crystal violet, and Lugol's solution.
The light source device for an endoscope according to any one of claims 1 to 18.
An imaging unit that images the observation object irradiated with the illumination light,
An endoscopic device comprising.
In claim 19.
It has a first normal light observation mode and a second normal light observation mode.
When the first normal light observation mode is set, the light source controller sets the second light amount ratio, which has a higher degree of emphasis than the second normal light observation mode, to display an image of the endoscope device. An endoscope device characterized in that the visibility of the region of interest in the above is higher than that of the second normal light observation mode.