JP4855728B2 - Illumination device and observation device - Google Patents

Description

  The present invention relates to an illumination device and an observation device that can prevent an optical member from being damaged by illumination light emitted from a light source.

  Conventionally, by inserting an electronic endoscope (hereinafter referred to as a scope) into a body cavity, digestive tracts such as the esophagus, stomach, small intestine, and large intestine, trachea such as lungs, and abdominal cavity can be observed. As an observation apparatus, an electronic endoscope apparatus is widely used. As a lamp of an illuminating device for supplying illumination light to a scope, a lamp that emits strong light even in the near-infrared light band such as a xenon lamp or a halogen lamp is often used.

  In recent years, in addition to normal observation using visible light as illumination light and displaying a color image similar to that observed with the naked eye on a monitor, special light observation using light of various wavelengths different from visible light has been performed. There has been proposed an electronic endoscope apparatus capable of performing the above (for example, see Patent Document 1). Examples of special light observation include autofluorescence observation, narrow-band light observation, infrared light observation, and infrared fluorescence observation.

  Autofluorescence observation is an observation method that uses autofluorescence of biological tissue. In autofluorescence observation, observation and diagnosis are performed using the fact that the spectrum of autofluorescence emitted from living tissue when irradiated with ultraviolet to blue excitation light is different between normal tissue and tumor. is there. An autofluorescence image obtained by autofluorescence observation is an image in which different colors are assigned to lesions such as tumors and normal tissues, along with a reflected light image based on the reflected light from living tissue obtained by irradiating irradiation light. Are generated by superimposing. Hereinafter, the illumination light applied to the subject to obtain the reflected light image is referred to as reference light. Therefore, in the autofluorescence image displayed on the monitor, the lesioned part and the normal tissue can be clearly identified as a color difference.

  Narrow band imaging (Narrow Band Imaging) is to perform observation by irradiating a subject with light having a narrower wavelength band than normal observation light. In narrow-band light observation, it is possible to observe blood vessels on the surface of the mucosa with good contrast. In addition, infrared light observation is performed by irradiating a subject with near infrared light. In infrared light observation, prior to observation, for example, indocyanine green (ICG) is injected into the blood vessel with a drug having an absorption peak in the near-infrared light wavelength band, so that the submucosal deep region that cannot be seen in normal observation is injected. It becomes possible to observe the hemodynamics of.

Infrared fluorescence observation is an observation method utilizing the fact that infrared fluorescent materials such as ICG and other related substances emit near-infrared fluorescence when excited by red to near-infrared light. In recent years, examination methods for early detection of neoplastic lesions have been studied by observing near-infrared fluorescence emitted from an ICG derivative-labeled antibody (ICG-related substance) that specifically accumulates in neoplastic lesions. . In addition, sentinel lymph that injects ICG into blood vessels and observes hemodynamics, administers ICG around the cancer nest, identifies the lymph node into which ICG has been taken up, considers it as a sentinel lymph node, and performs biopsy Infrared fluorescence observation is also effective for nodal biopsy.
Japanese Patent Laying-Open No. 2005-13611 (FIG. 1)

  In the conventional autofluorescence observation, a fluorescence observation filter having the characteristics shown in FIG. 20 is arranged on the optical path of the illumination light, and three excitation filters, G ′ filters, and R ′ filters having the characteristics shown in FIG. The rotating filter plate on which the filter is arranged is rotated, and the subject is irradiated with illumination light while sequentially inserting these three filters onto the optical path of the illumination light. FIG. 20 is a characteristic diagram of a fluorescence observation filter in a conventional illumination device. FIG. 21 is a characteristic diagram of each filter arranged in a rotary filter in a conventional lighting device.

  The autofluorescence emitted from the living tissue is very weak. Therefore, in order to make the brightness of the fluorescence and the brightness of the reflected light comparable, the amount of illumination light irradiated to obtain the reflected light image is excited. It may be very small compared to the amount of light. Therefore, in order to detect both fluorescence and reflected light using the same detector, the light transmittance of the G ′ filter and R ′ filter that generate the reference light for obtaining the reflected light image is reduced to about 1%. It is necessary to suppress. For this reason, in the conventional observation apparatus, an ND filter (Neutral Density filter) is bonded to the G ′ filter and the R ′ filter to adjust the transmittance to a desired level.

  On the other hand, the filter for fluorescence observation has a characteristic of transmitting light with a high transmittance over the entire wavelength band required for fluorescence observation. For this reason, it is necessary to use an expensive member having high heat resistance as an optical member such as a lens and its peripheral member installed between the fluorescence observation filter and the rotary filter plate.

  In conventional infrared fluorescence observation, it is common to display only the fluorescence image on the monitor without using the reflected light image. However, as in the case of autofluorescence observation, the reflected light image and the fluorescence image are displayed. It is also possible to superimpose and display on the monitor. In the infrared fluorescence observation, when a reflected light image is acquired, it is necessary to use light in a wide wavelength band from visible light to near infrared light. Compared with autofluorescence observation using light in a relatively narrow wavelength band of visible light, the amount of light transmitted through the filter for fluorescence observation increases, so in an illuminator using a filter configuration similar to autofluorescence observation, Therefore, further heat countermeasures are required.

  In addition, when the rotary filter plate is out of the optical path, light in all wavelength bands emitted from the illuminating device is transmitted to the scope tip, so that heat is generated at the scope tip and the optical member is damaged. There was a problem. In particular, in the xenon lamp and the halogen lamp, the amount of light in the near-infrared light band is larger than that in the visible light band. Therefore, in infrared fluorescence observation, damage to optical members due to heat tends to be more severe than in autofluorescence observation. Therefore, heat countermeasures were a very important issue.

  Accordingly, an object of the present invention is to provide an illuminating device and an observation device that can prevent the optical member from being damaged by heat caused by light emitted from the light source.

The illuminating device of the present invention is a near-infrared band for infrared fluorescence observation, which is arranged on the optical path of the illuminating light and configured to be detachable with respect to the optical path. A first filter that includes a first filter that transmits a wavelength band of infrared fluorescence excitation light including: a second filter that transmits a wavelength band of reference light; and an optical path of the illumination light; and A second filter disposed between the light source means and the first filter means and configured to transmit a wavelength band including a wavelength band of the infrared fluorescence excitation light and a wavelength band of the reference light; Filter means, and in the third filter, the transmittance of the reference light in the wavelength band is lower than the transmittance of the infrared fluorescence excitation light.

In addition, the observation apparatus of the present invention includes a light source means for generating illumination light, a light source means arranged on the optical path of the illumination light , configured to be detachable from the optical path, and a near red for infrared fluorescence observation. first filter and the first filter means and a second filter for transmitting a wavelength band of the reference light, an optical path of the illumination light that transmits the wavelength band of infrared fluorescence excitation light including an outer band, And a third filter disposed between the light source means and the first filter means and transmitting a wavelength band including a wavelength band of the infrared fluorescence excitation light and a wavelength band of the reference light. Two filter means, an imaging means for capturing an image of a subject by the infrared fluorescence excitation light and the reference light, and an excitation that is disposed between the subject and the imaging means and blocks the infrared fluorescence excitation light A light blocking filter, In the filter, the transmittance of the wavelength band of the reference light is made lower than the transmittance of the infrared fluorescence excitation light.

  It is possible to realize an illumination device and an observation device that can prevent the optical member from being damaged by the heat caused by the light emitted from the light source.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
First, based on FIG. 1, the structure of the endoscope apparatus using the light source device 2 as an illuminating device concerning the 1st Embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram illustrating the configuration of an endoscope apparatus using the light source device 2 according to the first embodiment of the present invention.

  As shown in FIG. 1, an endoscope apparatus according to an embodiment of the present invention includes a light source device 2 that generates illumination light for a subject 1 and a subject 1 such as an affected part in the body cavity that can be inserted into the body cavity. An imaging scope 3, a scope 3 is detachably connected, a processor 4 that performs signal processing on an image signal captured by the scope 3, and a monitor 5 that displays an image for a video signal output from the processor 4. It is configured.

  The light source device 2 emits light in the near-infrared to visible light wavelength band, and is provided on the optical path of illumination light emitted from the xenon lamp 11 as a light source means, and limits the transmission wavelength band. The band switching filter plate 12 as the second filter means and the motor 13 for switching the band switching filter plate 12 are provided. The light source device 2 includes a rotary filter plate 14 as a first filter means provided with a plurality of filters having different wavelength bands of light to be transmitted, a motor 15 for driving the rotary filter plate 14 to rotate, A motor 16 for moving the rotary filter plate 14 in a direction perpendicular to the optical axis of the illumination light (a direction indicated by an arrow A in FIG. 1) is also provided. That is, the rotary filter plate 14 can be inserted into and removed from the optical path of the illumination light. Further, on the optical path of the illumination light, lenses 18 and 19 as light refracting means for condensing and entering the illumination light emitted from the xenon lamp 11 on the end face of the light guide fiber 17 are arranged. ing.

  As shown in FIG. 2, the band switching filter plate 12 includes a normal observation filter 21, an infrared fluorescence observation filter 22 as a third filter, a narrowband light observation filter 23, and an infrared light observation filter. A filter 24 is arranged. FIG. 2 is a diagram illustrating the structure of the band switching filter plate 12. The transmission characteristics of the filters 21 to 24 arranged on the band switching filter plate 12 are as shown in FIGS. 3 is a transmission characteristic diagram of the normal observation filter 21 and the infrared light observation filter 24, FIG. 4 is a transmission characteristic diagram of the infrared fluorescence observation filter 22, and FIG. 6 is a diagram of the narrowband light observation filter 23. It is a transmission characteristic figure.

  As shown in FIG. 3, the normal observation filter 21 has a transmission characteristic 21 a that transmits light in a wavelength band of 400 nm to 660 nm. Further, the infrared light observation filter 24 has bimodal transmission characteristics 24a and 24b that allow light of two discrete wavelength bands to pass through by one filter. That is, the infrared light observation filter 24 has transmission characteristics 24a and 24b that transmit light in the wavelength bands of 790 nm to 850 nm and 860 nm to 980 nm. As described above, the infrared light observation filter 24 has the bimodal transmission characteristics 24a and 24b in which the transmittance of light in the wavelength band of 820 nm to 900 nm which is not used for observation is reduced, and thus transmits through the filter. The energy of the emitted light can be reduced, and deterioration or breakage of the optical member such as the lens 18, its antireflection film, or the member supporting the lens can be prevented.

  As shown in FIG. 4, the infrared fluorescence observation filter 22 transmits light in a wavelength band of 500 nm to 920 nm, and in particular has a high transmittance close to 100% in the wavelength band of 650 nm to 800 nm, which is excitation light. It has a transmission characteristic 22a that has a low transmittance of about 1% in other wavelength bands that become ', IR' light. The infrared fluorescence observation filter 22 having the transmission characteristic 22a as shown in FIG. 4 is configured by combining two filters 22A and 22B having different transmission characteristics 22A ′ and 22B ′ as shown in FIG. . FIG. 5 is a transmission characteristic diagram of the filters 22A and 22B constituting the infrared fluorescence observation filter 22. FIG.

  As described above, the infrared fluorescence observation filter 22 according to the present embodiment has the transmission characteristic 22a so as to have the minimum transmittance necessary for observation for each wavelength. Compared to the case where the IR ′ light wavelength band, that is, all the wavelength bands that transmit the filter have high transmittance, the energy of the transmitted light can be significantly reduced. Therefore, the influence of heat on the lens 18 by the light transmitted through the infrared fluorescence observation filter 22 can be suppressed, and deterioration or damage of the optical member such as the lens 18, its antireflection film, or the member supporting the lens can be prevented. Can be prevented.

  Basically, when the infrared fluorescence observation filter 22 is inserted on the optical path of the illumination light, the rotary filter plate 14 is controlled by a control circuit (not shown) so as to be arranged on the optical path. In a medical device used for inspection / treatment in a body cavity, such as an endoscope apparatus, it is important to ensure safety even when a control circuit breaks down. In the light source device 3 of the present embodiment, since the energy of light transmitted through the infrared fluorescence observation filter 22 is suppressed, the infrared fluorescence observation filter 22 is inserted in the optical path of the illumination light. Even if the rotary filter plate 14 is removed from the optical path, it is possible to suppress deterioration or damage of members in the optical path of the illumination light such as the distal end portion of the scope 3 due to heat.

  As shown in FIG. 6, the narrowband light observation filter 23 has three-peak transmission characteristics 23a, 23b, and 23c that allow light of three discrete wavelength bands to pass through with one filter. That is, the narrowband light observation filter 23 has transmission characteristics 23a, 23b, and 23c that transmit light in the wavelength bands of 400 nm to 430 nm, 530 nm to 560 nm, and 600 nm to 630 nm.

  As shown in FIG. 7, the rotary filter plate 14 is provided with an R filter 25, a G filter 26, and a B filter 27 that transmit light of red, green, and blue wavelengths on the outer periphery. FIG. 7 is a view for explaining the structure of the rotary filter plate 14. Further, on the inner periphery of the rotary filter plate 14, excitation light in a wavelength band of 670 nm to 785 nm is transmitted, excitation light 28 as a first filter is transmitted, and light in a wavelength band of 540 nm to 560 nm is transmitted. A G ′ filter 29 as a filter and an IR ′ filter 30 as a second filter that transmits light in a wavelength band of 890 nm to 900 nm are arranged.

  The transmission characteristics of the outer and inner filters are as shown in FIGS. 8 and 9, respectively. 8 is a transmission characteristic diagram of the R filter 25, the G filter 26, and the B filter 27, and FIG. 9 is a transmission characteristic diagram of the excitation filter 28, the G ′ filter 29, and the IR ′ filter 30. That is, as shown in FIG. 8, the R filter 25, the G filter 26, and the B filter 27 arranged on the outer periphery have transmission characteristics indicated by filter characteristics 25a, 26a, and 27a, respectively. In addition, each of the filters 25 to 27 arranged on the outer periphery has a characteristic of partially transmitting not only the wavelength band of visible light but also the wavelength band of near infrared light. Specifically, the R filter 25 and the G filter 26 have a characteristic of transmitting light in a wavelength band of 750 nm to 820 nm, and the B filter 27 has a characteristic of transmitting light in a wavelength band of 900 nm or more.

  The scope 3 transmits an elongated insertion portion 41 that can be inserted into a body cavity, an operation portion 42 provided on the proximal end side of the insertion portion 41, and illumination light emitted from the light source device 2 to the distal end of the insertion portion 41. And a light guide fiber 17 to be configured. The illumination light transmitted by the light guide fiber 17 is emitted toward the subject 1 through the objective optical system 43 provided at the distal end of the insertion portion 41. At the distal end of the insertion portion 41, an objective optical system 44a for infrared fluorescence observation is provided adjacent to the illumination objective optical system 43, and an optical image of the subject 1 is captured at the imaging position. A highly sensitive solid-state imaging device for infrared fluorescence observation (hereinafter referred to as CCD) 45a that performs photoelectric conversion is disposed. An excitation light cut filter 46 for removing excitation light and extracting fluorescence is disposed on the optical path between the objective optical system 44a and the infrared fluorescence observation CCD 45a.

  As shown in FIG. 10, the excitation light cut filter 46 has a transmission characteristic 46 a that transmits the infrared fluorescence wavelength band of 825 nm to 950 nm and the light of the wavelength band of 600 nm or less, and the wavelength band is the excitation filter. 28 so as not to overlap with the wavelength band of the light transmitted through 28. FIG. 10 is a transmission characteristic diagram of the excitation light cut filter 46.

  At the tip of the insertion portion 41, an objective optical system 44b for normal observation, narrowband light observation, and infrared light observation is provided adjacent to the objective optical system 44a for infrared fluorescence observation. At the position, a high-resolution CCD 45b for normal observation that picks up an optical image of the subject 1 and performs photoelectric conversion is arranged. Imaging signals generated by the CCDs 45 a and 45 b are output to the selector 47. In the selector 47, the imaging signal received from either one of the CCD 45 a and the CCD 45 b is selected and output to the processor 4.

  The operation unit 42 is provided with a filter switch 48 that instructs switching of illumination light by filter switching, and a scope ID memory 49 in which information related to the scope 3 is recorded. The scope ID memory 49 and the CPU 51 are electrically connected so that information recorded in the scope ID memory 49 can be read and written from the CPU 51 provided in the processor 4.

  The processor 4 includes a preprocess circuit 52, an A / D conversion circuit 53, a white balance correction circuit 54, a synchronization memory 55, a color matrix circuit 56, a color adjustment circuit 57, which perform preprocessing on the imaging signal output from the selector 47, A gamma circuit 58 and a D / A conversion circuit 59 are provided, and a video signal flows in this order. The imaging signal digitized by the A / D conversion circuit 53 is also output to the photometric circuit 60, and a photometric value is calculated. The photometric value calculated by the photometric circuit 60 is output to the CPU 51. The CPU 51 is electrically connected to external devices such as the light source device 2 and the scope 3 and each circuit inside the processor 4 such as the white balance correction circuit 54, the color matrix circuit 56, and the color adjustment circuit 57.

  Next, the operation of the endoscope apparatus configured as described above will be described. First, the light source device 2, the scope 3, the processor 4, and the monitor 5 are connected and these power supplies are turned on. Then, from the scope ID memory 49 to the CPU 51, an observation mode that can be handled by the scope 3, an applicable part of the scope 3 (for example, upper digestive tract, lower digestive tract, bronchus, etc.), correction parameters related to variation among individuals in the scope 3, etc. Is output. In addition, during observation, even when the scope 3 connected to the processor 4 is removed and another scope is attached, these pieces of information are output from the scope ID memory 49 to the CPU 51.

  The scope 3 in the present embodiment is capable of observation in four observation modes: normal observation, narrow band light observation, infrared light observation, and infrared fluorescence observation, and the filter switch 48 of the scope 3 is pressed. Thus, the observation mode can be switched. That is, each time the filter changeover switch 48 is pressed, the CPU 51 supplies the light source so that the observation light is sequentially switched in the order of normal observation → infrared fluorescence observation → narrow band light observation → infrared light observation → normal observation →. A filter switching instruction signal is output to the motors 13 and 16 of the apparatus 2.

  Next, in order to illuminate the subject, illumination light having a spectral radiation characteristic 11a as shown in FIG. 11 is emitted from the xenon lamp 11 of the light source device 2, for example. FIG. 11 is a radiation characteristic diagram of the xenon lamp 11. As shown in FIG. 11, the xenon lamp 11 has a strong emission line in the wavelength band of 800 nm to 1000 nm. The illumination light emitted from the xenon lamp 11 passes through the band switching filter plate 12, the lens 18, the rotary filter plate 14, and the lens 19 in order, and then enters the end face of the light guide fiber 17 of the scope 3.

  The band switching filter plate 12 is rotationally driven by a motor 13 in accordance with a filter switching instruction signal received from the CPU 51, and is a normal observation filter 21 for normal observation, an infrared fluorescence observation filter 22 for infrared fluorescence observation, and a narrow band light observation. A narrowband light observation filter 23 and an infrared light observation filter 24 are inserted on the optical path of the illumination light during infrared light observation.

  According to the filter switching instruction signal received from the CPU 51, the rotating filter plate 14 is inserted with an outer peripheral filter on the optical axis of the illumination light by the motor 16 during normal observation, narrowband light observation, and infrared light observation. Further, the R filter 25, the G filter 26, and the B filter 27 are sequentially inserted into the optical path by being rotationally driven at a predetermined speed by the motor 15.

  Due to the combination with the band switching filter plate 12, red, green and blue lights are normally observed during observation, light in wavelength bands of 400 nm to 430 nm, 530 nm to 560 nm, and 600 nm to 630 nm are observed during narrow band light observation, and during infrared light observation. , 790 nm to 820 nm, 790 nm to 820 nm, and 900 nm to 980 nm are transmitted through the rotary filter plate 14 and sequentially emitted from the light source device 2.

  Further, at the time of infrared fluorescence observation, the rotary filter plate 14 is moved in a direction orthogonal to the optical axis of the illumination light by the motor 16 in accordance with a filter switching instruction signal received from the CPU 51, so that the inner peripheral filter is illuminated. It is inserted on the optical axis of light. Furthermore, the excitation filter 28, the G ′ filter 29, and the IR ′ filter 30 are sequentially inserted into the optical path by being rotationally driven at a predetermined speed by the motor 15. In order to capture weak fluorescence with a long exposure time, the motor 15 filters at a half speed during infrared fluorescence observation compared to other observation modes (normal observation, narrow-band light observation, infrared light observation). The plate 14 is rotated.

  By combination with the band switching filter plate 12, as shown in FIG. 4, during infrared fluorescence observation, 540 nm to 560 nm (filter characteristic 29a ′ in FIG. 4), 670 nm to 785 nm (filter characteristic 28a ′ in FIG. 4), 890 nm. The light in the wavelength band of ˜900 nm (filter characteristic 30a ′ in FIG. 4) is transmitted through the rotary filter plate 14 and sequentially emitted from the light source device 2.

  Here, the light in the wavelength band of 670 nm to 785 nm is excitation light for exciting an agent such as an ICG derivative-labeled antibody administered into the body of the subject 1 to generate infrared fluorescence. Is a reference light for obtaining a reflected light image of the subject 1. As shown in FIG. 12, the ICG derivative-labeled antibody is a drug capable of generating fluorescence with excitation light of 670 nm to 785 nm. FIG. 12 is an excitation / fluorescence spectrum diagram of an ICG derivative-labeled antibody.

  Note that the light source device 2 in the present embodiment can also be used by being connected to a fiberscope that guides an optical image of the subject 1 to the eyepiece by using an image guide. When observing using a fiberscope, a normal observation filter 21 of the band switching filter plate 12 is inserted in the optical path of the illumination light by pressing a switch (not shown) provided in the light source device 2, and a rotating filter. The plate 14 is removed from the optical path, and the subject 1 is continuously irradiated with light in the entire wavelength band of visible light.

  In addition, the light source device 2 in the present embodiment can be used by being connected to an electronic scope on which a CCD is mounted. When observing using an electronic scope, a transmission illumination switch (not shown) provided in the light source device 2 is pushed, so that the normal observation filter 21 of the band switching filter plate 12 is inserted into the optical path of the illumination light, and The rotary filter plate 14 is removed from the optical path, and strong light is irradiated from the tip of the electronic scope. The observer can know the position where the electronic scope is inserted by viewing this light from outside the subject 1. Thus, the light source device 2 in the present embodiment is designed to be usable even when the rotary filter plate 14 is removed from the optical path of the illumination light depending on the type and operation of the connected scope.

  The light incident on the end face of the light guide fiber 17 of the scope 3 is irradiated to the subject 1 such as the digestive tract via the objective optical system 43 at the distal end of the scope 3. Light scattered, reflected, and radiated from the subject 1 is imaged and photoelectrically converted on the imaging surfaces of the fluorescence observation CCD 45a and the normal observation CCD 45b by the objective optical systems 44a and 44b provided at the distal end of the scope 3. To be imaged. An excitation light cut filter 46 is inserted between the objective optical system 44a and the fluorescence observation CCD 45a, and only infrared fluorescence is extracted by blocking excitation light of 670 nm to 785 nm. Further, the fluorescence observation CCD 45a has an electronic shutter function, and it is possible to adjust the color balance of the image by manually or automatically changing the exposure time of the fluorescence image and the reflected light image. It has become.

  The fluorescence observation CCD 45 a and the normal observation CCD 45 b are driven by a CCD drive circuit (not shown) in synchronization with the rotation of the rotary filter plate 14. As a result, imaging signals corresponding to the irradiation light transmitted through the filters of the rotary filter plate 14 such as the R filter 25, the G filter 26, and the B filter 27 are sequentially input to the selector 47. The selector 47 selects one of the imaging signals received from the fluorescence observation CCD 45 a or the normal observation CCD 45 b according to the control signal from the CPU 51 and outputs the selected image pickup signal to the processor 4. That is, the imaging signal received from the fluorescence observation CCD 45a is output to the processor 4 at the time of infrared fluorescence observation, and the imaging signal received from the normal observation CCD 45b at the time of normal observation, narrow-band light observation, and infrared light observation. Output to.

  The imaging signal output from the selector 47 is input to the preprocessing circuit 52 in the processor 4. In the preprocess circuit 52, processing such as CDS (correlated double sampling) is performed, and an image signal is extracted. The image signal output from the preprocess circuit 52 is converted from an analog signal to a digital signal by the A / D conversion circuit 53. The image signal output from the A / D conversion circuit 53 is input to the white balance correction circuit 54. In the white balance correction circuit 54, a WB (white balance) correction coefficient that differs for each irradiation wavelength is added to the image signal in synchronization with the rotation of the rotary filter 14 in order to correct the variation between the connected scope 3 individuals. Is multiplied. As the WB correction coefficient used in the white balance correction circuit 54, a value stored in the scope ID memory 49 is read out via the CPU 51, and is used by switching for each observation mode.

  The image signal output from the white balance correction circuit 54 is input to the synchronization memory 55, and frame-sequential synchronization is performed. The image signal output from the synchronization memory 55 is input to the color matrix circuit 56. In the color matrix circuit 56, some matrix coefficients are registered in advance, and are selected and used according to the observation mode. In addition, the observer can select one of several matrix coefficients even in the same observation mode. The image signal input to the color matrix circuit 56 is subjected to matrix color conversion using the selected matrix coefficient and output to the color adjustment circuit 57.

Matrix color conversion is a process of multiplying the image signal output from the synchronization memory 55 by the selected matrix coefficient. For example, in infrared fluorescence observation, a G ′ reflected light image signal (hereinafter referred to as G ′ signal), an infrared fluorescent image signal (hereinafter referred to as F signal), an IR ′ reflected light image signal (hereinafter referred to as IR ′). Is multiplied by the selected matrix coefficient, converted to a color signal (R, G, B signal) and output to the color adjustment circuit 57 (see equation (1)).

In the color matrix circuit 56, for example, four different matrix coefficients are registered for infrared fluorescence observation. The processor 4 is provided with a matrix selection switch (not shown) so that an arbitrary matrix coefficient can be selected from the four matrix coefficients. The matrix coefficient selected by the matrix selection switch is notified to the color matrix circuit 56 via the CPU 51. The color matrix circuit 56 performs matrix color conversion by substituting the received matrix coefficient into the equation (1) and calculating. Note that the matrix coefficients registered for infrared fluorescence observation are four types of matrices shown in Tables 1 to 4.

The matrix coefficients shown in Table 1 display the G ′ reflected light image as the R component on the monitor 5, the infrared fluorescent image as the G component on the monitor 5, and the IR ′ reflected light image as the B component on the monitor 5. Used when

The matrix coefficients shown in Table 2 are used when the G ′ reflected light image is displayed as the R and B components on the monitor 5 and the infrared fluorescent image is displayed as the G component on the monitor 5.

The matrix coefficients shown in Table 3 are used when the infrared fluorescent image is displayed as the G component on the monitor 5 and the IR ′ reflected light image is displayed as the R and B components on the monitor 5.

  The matrix coefficients shown in Table 4 are used when only the infrared fluorescent image is displayed on the monitor 5 in monochrome (black and white).

  In the color adjustment circuit 57, each color signal output from the color matrix circuit 56 is adjusted based on a color setting value set by an adjustment switch (not shown) or the like. The color setting value is used for the purpose of making the observation image displayed on the monitor 5 a color tone desired by the observer.

  The image signals Rin, Gin, Bin input to the white balance correction circuit 54 are subjected to various image processing as described above in the white balance correction circuit 54, the color matrix circuit 56, and the color adjustment circuit 57, and the image signals Rout, Gout. , Bout and output from the color adjustment circuit 57. The image signals Rin, Gin, and Bin are image signals obtained when the R filter 25, the G filter 26, and the B filter 27 of the rotary filter plate 14 are inserted into the optical path, respectively, during normal observation, for example. For example, during infrared fluorescence observation, these are image signals obtained when the excitation filter 28, the G ′ filter 29, and the IR ′ filter 30 of the rotary filter plate 14 are inserted into the optical path. Image signals Rout, Gout, and Bout output from the color adjustment circuit 57 are expressed by equations (2), (3), and (4), respectively.

Rout = Pr · α11 · Wr · Rin + Pr · β12 · Wg · Gin + Pr · γ13 · Wb · Bin (2)
Gout = Pg · α21 · Wr · Rin + Pg · β22 · Wg · Gin + Pg · γ23 · Wb · Bin (3)
Bout = Pb · α31 · Wr · Rin + Pb · β32 · Wg · Gin + Pb · γ33 · Wb · Bin (4)
Here, Wr, Wg, and Wb are white balance correction coefficients used in the white balance correction circuit 54, and Pr, Pg, and Pb are color adjustment coefficients used in the color adjustment circuit 57. In addition, α11, α21, α31, β12, β22, β32, γ13, γ23, and γ33 are matrix coefficients used in the color matrix circuit 56 (see equation (1)).

  The image signals Rout, Gout, and Bout output from the color adjustment circuit 57 are input to the gamma correction circuit 58, and a conversion process for correcting the gamma characteristic of the monitor 5 is performed. The image signal output from the gamma correction circuit 58 is input to the D / A conversion circuit 59 and converted from a digital signal to an analog signal. The image signal output from the D / A conversion circuit 59 is output to the monitor 5 and displayed as an observation image.

  In the photometry circuit 60, the value of the image signal output from the A / D conversion circuit 53 to the white balance correction circuit 54 is sampled, and a photometric value such as luminance is calculated. In the photometry circuit 60, as shown in the equation (5), the three correction coefficients Cr, Cg, and Cb and the image signals Rin, Gin, and the like that are output from the A / D conversion circuit 53 and input to the white balance correction circuit 54 are shown. The photometric value Ys is calculated using the Bin sampling values Sr, Sg, and Sb.

Ys = Cr.Sr + Cg.Sg + Cb.Sb (5)
Here, the three correction coefficients Cr, Cg, and Cb are the values of various coefficients used in the white balance correction circuit 54, the color matrix circuit 56, and the color adjustment circuit 57, such as the luminance of the observation image displayed on the monitor 5. This coefficient is used to remove the influence of the value, and is calculated by the CPU 51. During normal observation, narrowband light observation, and infrared light observation, correction coefficients Cr, Cg, and Cb are calculated using the following equations (6), (7), and (8).

Cr = (0.3 · Pr · α11 + 0.6 · Pg · α21 + 0.1 · Pb · α31) · Wr (6)
Cg = (0.3 · Pr · β12 + 0.6 · Pg · β22 + 0.1 · Pb · β32) · Wg (7)
Cb = (0.3 · Pr · γ13 + 0.6 · Pg · γ23 + 0.1 · Pb · γ33) · Wb (8)
In infrared fluorescence observation, unlike these other observation modes, if a drug such as an ICG derivative-labeled antibody is not present in the subject, the display channel to which infrared fluorescence is assigned becomes black. . Therefore, when the correction coefficient is calculated using the equations (6), (7), and (8), the color to which the reflected light image by the G ′ light and IR ′ light other than the infrared fluorescence is assigned is saturated on the monitor 5. Therefore, an observation image with appropriate brightness cannot be obtained. Accordingly, in the infrared fluorescence observation, the above-described influence is taken into consideration, and correction coefficients different from those in other observation modes are calculated using the equations (9), (10), and (11).

Cr = (0.3 · Pr · α11 + 0.9 · Pg · α21 + 0.3 · Pb · α31) · Wr (9)
Cg = (0.3 · Pr · β12 + 0.9 · Pg · β22 + 0.3 · Pb · β32) · Wg (10)
Cb = (0.3 · Pr · γ13 + 0.9 · Pg · γ23 + 0.3 · Pb · γ33) · Wb (11)
Note that when only the infrared fluorescent image is displayed in monochrome (black and white) on the monitor 5, the above-mentioned problem does not occur, and therefore the correction coefficient is calculated using equations (12), (13), and (14).

Cr = (0.0 · Pr · α11 + 1.2 · Pg · α21 + 0.0 · Pb · α31) · Wr (12)
Cg = (0.0 · Pr · β12 + 1.2 · Pg · β22 + 0.0 · Pb · β32) · Wg (13)
Cb = (0.0 · Pr · γ13 + 1.2 · Pg · γ23 + 0.0 · Pb · γ33) · Wb (14)
In the infrared fluorescent image, since the medicine is often present only on a part of the screen of the monitor 5, it is necessary to suppress the brightness of the screen so that the screen is not saturated even in such a case. (13) In the formula (14), the coefficient of Pg is set to 1.2 instead of 1.0. In an AGC (auto gain control) circuit (not shown), the photometric value is calculated by substituting the correction coefficients Cr, Cg, and Cb calculated as described above into the equation (5).

  As described above, the photometric circuit 60 calculates the photometric value Ys corresponding to the observation mode and the display method in consideration of the white balance correction coefficient, the matrix coefficient, and the color adjustment coefficient. The photometric value Ys calculated by the photometric circuit 60 is output to the light source device 2 via the CPU 51, and a light amount stop (not shown) provided in the light source device 2 so that the photometric value Ys is always kept at an appropriate level. And an AGC circuit (not shown) is controlled.

  As described above, in the light source device 2 of the present embodiment, the transmission characteristics are such that the infrared fluorescence observation filter 22 provided on the band switching filter plate 12 has the minimum transmittance necessary for observation for each wavelength. Therefore, the influence of heat on the lens 18 by the light emitted from the xenon lamp 11 that is a light source and transmitted through the infrared fluorescence observation filter 22 can be suppressed, and the lens 18 and its antireflection film, Deterioration or breakage of an optical member such as a member that supports the lens can be prevented. In addition, since the energy of light transmitted through the infrared fluorescence observation filter 22 of the band switching filter plate 12 is suppressed, even if the rotary filter plate 14 is removed from the optical path during observation, illumination of the distal end portion of the scope 4 is performed. It can suppress that the member in the optical path of light deteriorates or is damaged by heat.

  In the present embodiment, the transmittance in the wavelength band of G ′ light to IR ′ light in the infrared fluorescence observation filter 22 is about 1%, but it is not necessarily required to be 1%. What is necessary is just to set to the transmittance | permeability which can suppress the energy of the light after permeate | transmitting the filter 22 for infrared fluorescence observation to the desired value. For example, if the transmittance is in the range of 0.1% to 50%, a considerable reduction in the amount of light can be expected as compared with the conventional light source device.

  When the transmission characteristic 22a of the infrared fluorescence observation filter 22 is changed as described above, the balance of the brightness of the fluorescence emitted from the subject 1 and the reflected light also changes. By changing the transmission characteristics 29a and 30a of the G ′ filter 29 and the IR ′ filter 30 and shortening the exposure time when the reflected light is received using the electronic shutter function of the CCD, the fluorescence and reflected light can be reduced. It is desirable to adjust the brightness balance. For example, when the transmittance of the G ′ light wavelength band to the IR ′ light wavelength band in the infrared fluorescence observation filter 22 is 50%, the transmittance of the G ′ filter 29 and the IR ′ filter 30 of the rotary filter plate 14. May be about 2%. When observing the subject 1 with low fluorescence brightness, it may be preferable to set the transmittance of the G ′ filter 29 and the IR ′ filter 30 of the rotary filter plate 14 to less than 1%.

  Further, in the present embodiment, the rotary filter is used for both the band switching filter plate 12 and the rotary filter plate 14, but a reflective filter such as a mirror having a predetermined reflection characteristic may be used.

  Furthermore, in the present embodiment, the light amount diaphragm (not shown) of the light source device 2 is automatically controlled according to the photometric value Ys calculated by the photometric circuit 60, but the amount of fluorescence on the desk is quantified. In the case of performing an evaluation, a switch for manually adjusting the gain by disabling AGC (auto gain control) may be provided, and the aperture position of the xenon lamp 11 may be fixed in conjunction with the operation of the switch. . When the manual gain is selected by the switch, the aperture position can be fixed by causing the photometric circuit 60 to output a sufficiently small value as the photometric value Ys.

(Second Embodiment)
Next, the configuration of an endoscope apparatus using the light source device 71 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 13 is a schematic configuration diagram illustrating the configuration of the light source device 71 and the scope 74 according to the second embodiment of the present invention. In the endoscope apparatus according to the first embodiment, an observation image composed of an infrared fluorescence observation image and a reflected light image is displayed on the monitor 5 during infrared fluorescence observation. In the endoscope apparatus of this form, at the time of infrared fluorescence observation, in addition to the infrared fluorescence observation image and the reflected light image, the autofluorescence image is displayed on the monitor 5 together.

  The overall configuration of the endoscope apparatus is different in the configuration of filters provided on the band switching filter plate 72 and the rotary filter plate 73 of the light source device 71, and between the light guide fiber 17 of the scope 74 and the objective optical system 43. The second embodiment is the same as the first embodiment except that the second excitation filter 75 is provided and the transmission characteristic 76a of the excitation light cut filter 76 of the scope 74 is different. Accordingly, only the above-described points that are different from the first embodiment will be described here, and the same components are denoted by the same reference numerals and description thereof will be omitted.

  As shown in FIG. 14, the band switching filter plate 72 provided in the light source device 71 of the present embodiment includes a normal observation filter 21, a fluorescence observation filter 81, a narrowband light observation filter 23, and a red color. An external light observation filter 24 is disposed. FIG. 14 is a view for explaining the structure of the band switching filter plate 72. As shown in FIG. 15, the fluorescence observation filter 81 arranged on the band switching filter plate 72 transmits light in a wavelength band of 390 nm to 785 nm, and in particular, has a wavelength band of 390 nm to 440 nm that becomes autofluorescence excitation light. The transmission characteristic 81a has a high transmittance close to 100% in the wavelength band of 670 nm to 785 nm serving as infrared fluorescence excitation light, and a low transmittance of about 1% in the wavelength band serving as G ′ light. FIG. 15 is a transmission characteristic diagram of the fluorescence observation filter 81.

  As described above, the fluorescence observation filter 81 according to the present embodiment has the transmission characteristic 81a so as to obtain the minimum transmittance necessary for observation for each wavelength. Compared with the case where the transmittance is high in the wavelength band of the external fluorescence excitation light, that is, in all the wavelength bands that transmit the filter, the energy of the transmitted light can be greatly reduced.

  As shown in FIG. 16, the rotary filter plate 73 provided in the light source device 71 has an R filter 25, a G filter 26, and a B filter 27 that transmit light of red, green, and blue wavelengths on the outer periphery. Yes. FIG. 16 is a view for explaining the structure of the rotary filter plate 73. In addition, on the inner periphery of the rotary filter plate 73, as shown in FIG. 17, excitation filter 28 that transmits light in the wavelength band of 670 nm to 785 nm that is infrared fluorescence excitation light, light in the wavelength band of 540 nm to 560 nm. A G ′ filter 29 that transmits light and an autofluorescence excitation filter 82 that transmits light in a wavelength band of 390 nm to 440 nm, which is autofluorescence excitation light that excites autofluorescence of the biological mucous membrane, are disposed. FIG. 17 is a transmission characteristic diagram of the excitation filter 28, the G ′ filter 29, and the autofluorescence excitation filter 82.

  The second excitation filter 75 provided in the scope 74 is a filter for blocking fluorescence in a wavelength band of 800 nm or more, which is a noise component caused by impurities contained in the light guide fiber 17. By providing the second excitation filter 75, the contrast of the infrared fluorescent image becomes better. As shown in FIG. 18, the second excitation filter 75 has a transmission characteristic indicated by a filter characteristic 75a. FIG. 18 is a transmission characteristic diagram of the second excitation filter 75.

  As shown in FIG. 19, the excitation light cut filter 76 transmits light having a wavelength band of 390 nm to 440 nm that is transmitted through the autofluorescence excitation filter 82 and becomes autofluorescence excitation light, and transmits the excitation filter 28 and infrared fluorescence excitation light. By blocking the light in the wavelength band of 670 nm to 785 nm and transmitting the wavelength band of infrared fluorescence of 825 nm to 950 nm and the wavelength band of autofluorescence of 480 nm to 600 nm, infrared fluorescence and autofluorescence are obtained. It has bimodal transmission characteristics 76a and 76b so that it can be extracted. FIG. 19 is a transmission characteristic diagram of the excitation light cut filter 76.

  Next, the operation of the endoscope apparatus configured as described above will be described. Except for the action at the time of infrared fluorescence observation, the operation is the same as that of the first embodiment, so only the action at the time of infrared fluorescence observation will be described here.

  In order to illuminate the subject, the illumination light emitted from the xenon lamp 11 of the light source device 2 sequentially passes through the fluorescence observation filter 81, the lens 18, the rotary filter plate 73, and the lens 19 of the band switching filter plate 72. The light enters the end face of the light guide fiber 17 of the scope 74.

  During infrared fluorescence observation, the inner filter of the rotary filter plate 73 is inserted on the optical axis of the illumination light. Further, the excitation filter 28, the G ′ filter 29, and the autofluorescence excitation filter 82 are sequentially inserted into the optical path by being rotationally driven at a predetermined speed by the motor 15. By combination with the band switching filter plate 72, light in the wavelength bands of 540 nm to 560 nm, 670 nm to 785 nm, and 390 nm to 440 nm are respectively transmitted through the rotary filter plate 73 and sequentially emitted from the light source device 71 during infrared fluorescence observation. The

  The light incident on the end face of the light guide fiber 17 of the scope 74 passes through the second excitation filter 75 at the distal end of the scope 74 and is blocked from light having a wavelength band of 800 nm or more. Through the subject 1 such as the digestive tract. The light scattered, reflected, and emitted from the subject 1 is imaged on the imaging surface of the fluorescence observation CCD 45a by the objective optical system 44a provided at the tip of the scope 74, and is photoelectrically converted and imaged. An excitation light cut filter 76 is inserted between the objective optical system 44a and the fluorescence observation CCD 45a, and only infrared fluorescence and autofluorescence are extracted.

  The image signal picked up by the fluorescence observation CCD 45a is output to the processor 4 through the selector 47, subjected to the same image processing as in the first embodiment, and then output to the monitor 5 to be displayed as an observation image. Is done. In addition, by giving an appropriate matrix coefficient to the color matrix circuit 56, for example, an infrared fluorescent image is an R component of the monitor 5, an autofluorescent image is a G component of the monitor 5, and a G ′ reflected light image is a B component of the monitor 5. Can be displayed. Further, by giving another matrix coefficient, it is also possible to display only the autofluorescence image in green and monochrome, or display only the infrared fluorescence image in monochrome.

  As described above, in the light source device 71 of the present embodiment, the fluorescence observation filter 81 provided on the band switching filter plate 72 has transmission characteristics such that the minimum transmittance necessary for observation is obtained for each wavelength. Therefore, the influence of heat applied to the lens 18 by the light emitted from the xenon lamp 11 that is a light source and transmitted through the fluorescence observation filter 81 can be suppressed, and the lens 18, its antireflection film, and the lens are supported. Deterioration or breakage of an optical member such as a member can be prevented. In addition, since the energy of the light transmitted through the fluorescence observation filter 81 of the band switching filter plate 72 is suppressed, even if the rotary filter plate 73 is removed from the optical path during observation, illumination light such as the distal end portion of the scope 74 is not affected. It can suppress that the member etc. in an optical path deteriorate or break with heat.

  From the above embodiment, there is a feature in the points described in the following additional items.

  (Additional Item 1) Light source means for generating illumination light, a first filter that is disposed on the optical path of the illumination light and that passes the wavelength band of the excitation light, and a second filter that passes the wavelength band of the reference light A first filter means having an optical path of the illumination light and between the light source means and the first filter means, and passing the wavelength band of the excitation light and the wavelength band of the reference light, And a second filter means having a third filter for reducing the amount of light in the wavelength band of the reference light.

  (Additional Item 2) The illuminating device according to Additional Item 1, wherein a light refracting unit is provided between the first filter unit and the second filter unit.

  (Additional Item 3) The illuminating device according to Additional Item 1 or Additional Item 2, wherein the first filter unit is detachably disposed in an optical path of the illumination light.

  (Additional Item 4) In any one of Additional Item 1 to Additional Item 3, wherein at least a part of the wavelength band of the excitation light or the wavelength band of the reference light is a near infrared light band. The lighting device described.

  (Additional Item 5) The illumination device according to any one of Additional Items 1 to 4, wherein the third filter reduces the light amount of the wavelength band of the reference light to 50% or less. .

  (Additional Item 6) Imaging means for imaging a subject, excitation light cut filter provided between the subject and the imaging means, for cutting excitation light, and light source means for generating illumination light for illuminating the subject A first filter means disposed on the optical path of the illumination light and having a first filter that passes the wavelength band of the excitation light and a second filter that passes the wavelength band of the reference light; and the illumination light Is disposed between the light source unit and the first filter unit, and passes the wavelength band of the excitation light and the wavelength band of the reference light, and reduces the amount of light in the wavelength band of the reference light. An observation apparatus comprising: second filter means having a third filter.

  (Additional Item 7) The observation apparatus according to Additional Item 6, wherein a light refraction unit is provided between the first filter unit and the second filter unit.

  (Additional Item 8) The observation apparatus according to Additional Item 6 or Additional Item 7, wherein the first filter unit is detachably disposed in the optical path of the illumination light.

  (Additional Item 9) In any one of Additional Items 6 to 8, wherein at least part of the wavelength band of the excitation light or the wavelength band of the reference light is a near-infrared light band. The observation apparatus described.

  (Additional Item 10) The observation apparatus according to any one of Additional Items 6 to 9, wherein the third filter reduces the amount of light in the wavelength band of the reference light to 50% or less. .

It is a schematic block diagram explaining the structure of the endoscope apparatus using the light source device 2 concerning the 1st Embodiment of this invention. It is a figure explaining the structure of the band switching filter board. It is a transmission characteristic figure of filter 21 for normal observation, and filter 24 for infrared light observation. It is a transmission characteristic figure of filter 22 for infrared fluorescence observation. It is a transmission characteristic figure of filters 22A and 22B which constitute filter 22 for infrared fluorescence observation. It is a transmission characteristic figure of filter 23 for narrow-band light observation. It is a figure explaining the structure of the rotation filter board. FIG. 6 is a transmission characteristic diagram of an R filter 25, a G filter 26, and a B filter 27. 4 is a transmission characteristic diagram of an excitation filter 28, a G ′ filter 29, and an IR ′ filter 30. FIG. 7 is a transmission characteristic diagram of an excitation light cut filter 46. FIG. 2 is a radiation characteristic diagram of a xenon lamp 11. FIG. It is an excitation and fluorescence spectrum figure of an ICG derivative labeled antibody. It is a schematic block diagram explaining the structure of the light source device 71 and the scope 74 concerning the 2nd Embodiment of this invention. It is a figure explaining the structure of the band switching filter board. It is a transmission characteristic figure of filter 81 for fluorescence observation. It is a figure explaining the structure of the rotation filter board 73. FIG. 7 is a transmission characteristic diagram of an excitation filter 28, a G ′ filter 29, and an autofluorescence excitation filter 82. FIG. FIG. 10 is a transmission characteristic diagram of the second excitation filter 75. It is a transmission characteristic figure of excitation light cut filter 76. It is a characteristic view of the filter for fluorescence observation in the conventional illuminating device. It is a characteristic view of each filter arrange | positioned at the rotation filter in the conventional illuminating device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Light source device, 3 ... Scope, 4 ... Processor, 5 ... Monitor, 11 ... Xenon lamp, 12 ... Band change filter board, 13, 15, 16 ... Motor, 14 ... Rotation filter board, 18, 19 ... Lens, 22 ... Infrared fluorescence observation filter, 28 ... Excitation filter, 29 ... G 'filter, 30 ... IR' filter, 22a, 28a ', 29a', 30a '... Transmission characteristics

Claims (8)

Light source means for generating illumination light;
A first light beam disposed on the optical path of the illumination light and configured to be detachable with respect to the optical path and transmitting a wavelength band of infrared fluorescence excitation light including a near infrared band for infrared fluorescence observation . first filter means and a second filter transmitting a filter, the wavelength band of the reference beam,
It is disposed on the optical path of the illumination light and between the light source means and the first filter means, and transmits a wavelength band including the wavelength band of the infrared fluorescence excitation light and the wavelength band of the reference light. Second filter means having a third filter,
In the third filter, the illumination device is characterized in that a transmittance in a wavelength band of the reference light is lower than a transmittance of the infrared fluorescence excitation light. The lighting device according to claim 1, wherein the transmittance of the second filter is lower than the transmittance of the first filter. The illumination apparatus according to claim 1, further comprising a light refracting unit provided between the first filter unit and the second filter unit. The lighting device according to any one of claims 1 to 3, wherein the third filter reduces the amount of light in the wavelength band of the reference light to 50% or less. Light source means for generating illumination light;
A first light beam disposed on the optical path of the illumination light and configured to be detachable with respect to the optical path and transmitting a wavelength band of infrared fluorescence excitation light including a near infrared band for infrared fluorescence observation . first filter means and a second filter transmitting a filter, the wavelength band of the reference beam,
It is disposed on the optical path of the illumination light and between the light source means and the first filter means, and transmits a wavelength band including the wavelength band of the infrared fluorescence excitation light and the wavelength band of the reference light. A second filter means having a third filter;
Imaging means for capturing an image of a subject by the infrared fluorescence excitation light and the reference light;
An excitation light blocking filter disposed between the subject and the imaging means and blocking the infrared fluorescence excitation light;
In the third filter, the observation device is characterized in that a transmittance in a wavelength band of the reference light is lower than a transmittance of the infrared fluorescence excitation light. The observation apparatus according to claim 5, wherein the transmittance of the second filter is lower than the transmittance of the first filter. The first filter means further includes a fourth filter that transmits a wavelength band of autofluorescence excitation light, and the third filter transmits a wavelength band of the autofluorescence excitation light. Item 2. The lighting device according to Item 1. The first filter means further includes a fourth filter that transmits a wavelength band of autofluorescence excitation light, and the third filter transmits a wavelength band of the autofluorescence excitation light. Item 6. The observation device according to Item 5.

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