WO2017141415A1 - Endoscope light source device - Google Patents

Abstract

This endoscope light source device is constituted by: a light source unit that is provided with a first solid state light-emitting element and a first and a second fluorescent body, and that projects illumination light comprising light within a first wavelength band projected from the first solid state light-emitting element, first fluorescent light emitted by the first fluorescent body, and second fluorescent light emitted by the second fluorescent body; a wavelength-limiting filter that transmits only light within a specific wavelength band from among the illumination light; and a filter inserting/removing means that supports the wavelength-limiting filter such that the filter can be inserted and removed with respect to the light path of the illumination light. When the wavelength-limiting filter is inserted into the light path, the illumination light is supplied to the endoscope filtered into light which comprises the light in the first wavelength band and the second fluorescent light. When the wavelength-limiting filter is removed from the light path, the illumination light is supplied to the endoscope without filtering.

Description

Endoscope light source device

The present invention relates to an endoscope light source device for irradiating a subject with light.

An endoscope system that can change the spectral intensity characteristics of irradiated light and take a special image is known. For example, Japanese Unexamined Patent Application Publication No. 2009-165889 (hereinafter referred to as “Patent Document 1”) describes a specific configuration of a light source device used in this type of endoscope system.

The endoscope system described in Patent Document 1 includes a light source device equipped with a xenon lamp and a plurality of band switching filters that limit the wavelength band of illumination light emitted from the xenon lamp. The band switching filter is a normal light observation filter that transmits light in the visible light band, an infrared observation filter that transmits only light in the infrared region, and transmits light in a specific wavelength band among light in the visible light band. A special light observation filter. By inserting one of the plurality of band switching filters into the optical path of the illumination light, it is possible to switch the spectral intensity characteristic of the illumination light irradiated on the subject. For example, when a normal light observation filter is inserted in the optical path of illumination light, the subject is illuminated with white normal light, and a normal color photographed image can be obtained. In addition, when the special light observation filter is inserted into the optical path of the illumination light, it is possible to obtain a captured image in which a specific tissue is emphasized among subjects in the living body.

The light source device described in Patent Document 1 uses a xenon lamp as a light source. On the other hand, in recent years, solid-state light-emitting elements such as light-emitting diodes (LEDs: Light Emitting Diodes) have been increasing in brightness, and there is a demand for using a solid-state light-emitting element having a longer life as a light source. The wavelength band of a solid state light emitting device is narrower than that of a xenon lamp. Therefore, for example, pseudo white light is generated by combining an LED emitting blue LED light and a phosphor emitting yellow fluorescence. However, there is a problem that the spectral intensity distribution of normal light does not become flat in the visible light band and the color reproducibility of the photographed image of the photographed subject is poor only by combining the LED and the phosphor in this way.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope light source device that uses a solid light emitting element as a light source and can improve the color reproducibility of a captured image of a subject. Is to provide.

An endoscope light source device according to an embodiment of the present invention includes a first solid-state light emitting element, first and second phosphors, and a first wavelength band emitted from the first solid-state light emitting element. Light emitted from the first fluorescent material, the first fluorescent light emitted from the first fluorescent material, and the second fluorescent material emitted from the second fluorescent material, the second fluorescent light having a peak wavelength different from the peak wavelength of the first fluorescent light. A light source unit, a wavelength limiting filter that transmits only light in a specific wavelength band of the illumination light, and a filter insertion / extraction unit that supports the wavelength limitation filter so that it can be inserted into and extracted from the optical path of the illumination light. In this configuration, when the wavelength limiting filter is inserted into the optical path of the illumination light by the filter insertion / extraction means, the illumination light is filtered into the light including the first wavelength band and the second fluorescence and supplied to the endoscope. Is done. When the wavelength limiting filter is removed from the optical path of the illumination light by the filter insertion / extraction means, the illumination light is supplied to the endoscope without being filtered by the wavelength limiting filter.

According to such a configuration, by inserting / removing the wavelength limiting filter into / from the optical path of the illumination light, the illumination light has a narrow wavelength band as compared with normal light having a wide wavelength band in the visible light band and normal light. Can switch between special light. In addition, since the endoscope light source device includes the first solid-state light emitting element and the two phosphors, the spectral intensity distribution of normal light can be made flat in the visible light band. Thereby, a captured image with high color reproducibility can be obtained.

In one embodiment of the present invention, the light source unit further includes, for example, a second solid state light emitting element. In this case, the illumination light further includes light in the second wavelength band emitted from the second solid state light emitting device.

In one embodiment of the present invention, the light source unit further includes, for example, an excitation solid-state light emitting element that emits excitation light. In this case, the first phosphor is excited by light in the first wavelength band emitted from the first solid state light emitting device, and the second phosphor is excited by excitation light emitted from the excitation solid state light emitting device. Excited.

In one embodiment of the present invention, the first phosphor and the second phosphor are excited by, for example, light in the first wavelength band emitted from the first solid state light emitting device.

Also, in one embodiment of the present invention, the first phosphor and the second phosphor are excited by, for example, light in the second wavelength band emitted from the second solid state light emitting device.

In one embodiment of the present invention, the light source unit includes, for example, a third phosphor that emits third fluorescence having a peak wavelength different from the peak wavelength of the first fluorescence and the peak wavelength of the second fluorescence. Also have. In this case, the illumination light further includes third fluorescence.

In one embodiment of the present invention, the light source unit includes, for example, a first light source unit having a first solid state light emitting element and a first phosphor, and a second light source unit having a second phosphor. And an optical path combining means for combining the optical path of the light emitted from the first light source unit and the optical path of the light emitted from the second light source unit to supply illumination light to the endoscope.

In one embodiment of the present invention, the first light source unit includes, for example, a phosphor inserting / removing unit that supports the first phosphor so that the first phosphor can be inserted into and removed from the optical path of light emitted from the first solid state light emitting device. It has further. In this case, when the wavelength limiting filter is inserted into the optical path of the illumination light by the filter insertion / extraction means, the phosphor insertion / extraction means extracts the first phosphor from the optical path of the light emitted from the first solid state light emitting device, and the filter When the wavelength limiting filter is removed from the optical path of the illumination light by the insertion / extraction means, the phosphor insertion / extraction means inserts the first phosphor into the optical path of the light emitted from the first solid state light emitting device.

According to an embodiment of the present invention, there is provided an endoscope light source device that can improve the color reproducibility of a captured image of a subject using a solid light emitting element as a light source.

1 is a block diagram illustrating a configuration of an electronic endoscope system according to a first embodiment of the present invention. It is a block diagram of the light source device for endoscopes concerning a 1st embodiment of the present invention. It is a figure which shows the spectral transmission characteristic of the wavelength limiting filter which concerns on the 1st Embodiment of this invention. It is a block diagram of the light source device for endoscopes concerning a 1st embodiment of the present invention. It is a figure which shows the spectral intensity distribution of the irradiation light inject | emitted from the light source device for endoscopes which concerns on the 1st Embodiment of this invention. It is a block diagram of the light source device for endoscopes which concerns on the 2nd Embodiment of this invention. It is a figure which shows the spectral intensity distribution of the irradiated light inject | emitted from the light source device for endoscopes which concerns on the 2nd Embodiment of this invention. It is a block diagram of the light source device for endoscopes which concerns on the 3rd Embodiment of this invention. It is a figure which shows the spectral intensity distribution of the irradiation light inject | emitted from the light source device for endoscopes which concerns on the 3rd Embodiment of this invention. It is a block diagram of the light source device for endoscopes which concerns on the 4th Embodiment of this invention. It is a figure which shows the spectral intensity distribution of the irradiated light inject | emitted from the light source device for endoscopes which concerns on the 4th Embodiment of this invention. It is a block diagram of the light source device for endoscopes which concerns on the 5th Embodiment of this invention. It is a figure which shows the spectral intensity distribution of the irradiated light inject | emitted from the light source device for endoscopes which concerns on the 5th Embodiment of this invention. It is a block diagram of the light source device for endoscopes which concerns on the 6th Embodiment of this invention. It is a figure which shows the spectral intensity distribution of the irradiated light inject | emitted from the light source device for endoscopes which concerns on the 6th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, an electronic endoscope system including an endoscope light source device will be described as an embodiment of the present invention.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of an electronic endoscope system 1 including an endoscope light source device 201 according to the first embodiment of the present invention. As shown in FIG. 1, the electronic endoscope system 1 is a system specialized for medical use, and includes an electronic scope 100, a processor 200, and a monitor 300.

The processor 200 includes a system controller 21 and a timing controller 22. The system controller 21 executes various programs stored in the memory 23 and controls the entire electronic endoscope system 1 in an integrated manner. The system controller 21 is connected to the operation panel 24. The system controller 21 changes each operation of the electronic endoscope system 1 and parameters for each operation in accordance with an instruction from the operator input from the operation panel 24. The input instruction by the operator includes, for example, an instruction to switch the observation mode of the electronic endoscope system 1. The observation mode includes a normal observation mode and a special observation mode. Details of each observation mode will be described later. The timing controller 22 outputs a clock pulse for adjusting the operation timing of each unit to each circuit in the electronic endoscope system 1.

The processor 200 includes a light source device 201. FIG. 2 is a block diagram of the light source device 201 according to the first embodiment of the present invention. The light source device 201 includes a first light source unit 111 and a second light source unit 112. The first and second light source units 111 and 112 are individually controlled to emit light by the first and second light source drive circuits 141 and 142, respectively.

The first light source unit 111 includes a purple light emitting diode (LED: Light Emitting Diode) 111a that emits light in a purple wavelength band (for example, a wavelength of 395 to 435 nm) and a blue phosphor 111b. The blue phosphor 111b is excited by the purple LED light emitted from the purple LED 111a and emits fluorescence in a blue wavelength band (for example, a wavelength of 430 to 550 nm).

The blue phosphor 111b is supported by the phosphor insertion / extraction mechanism 151 so that it can be inserted into and removed from the optical path. Specifically, the blue phosphor 111b is inserted into or removed from the optical path of the purple LED light emitted from the purple LED 111a according to the observation mode. As shown by a solid line in FIG. 2, when the blue phosphor 111b is inserted on the optical path of the purple LED light, the blue phosphor 111b emits blue fluorescence. Thereby, both the purple LED light and the blue fluorescence are emitted from the light source unit 111. Further, as shown by the dotted line in FIG. 2, when the blue phosphor 111b is removed from the optical path of the purple LED light, the blue phosphor 111b is not excited and does not emit fluorescence. Therefore, only the purple LED light is emitted from the light source unit 111.

The second light source unit 112 includes a blue LED 112a that emits light in a blue wavelength band (for example, a wavelength of 420 to 480 nm), and a yellow phosphor 112b. The yellow phosphor 112b is excited by the blue LED light emitted from the blue LED 112a, and emits fluorescence in a yellow wavelength band (for example, a wavelength is 420 to 700 nm). The yellow phosphor 112b is attached on the light emitting surface of the blue LED 112a, and unlike the blue phosphor 111b, it cannot be inserted into and removed from the optical path of the blue LED light.

Collimating lenses 121 and 122 are arranged in front of the light source units 111 and 112 in the light emission direction, respectively. The light emitted from the first light source unit 111 is converted into parallel light by the collimator lens 121 and is incident on the dichroic mirror 131. The light emitted from the second light source unit 112 is converted into parallel light by the collimator lens 122 and is incident on the dichroic mirror 131. The dichroic mirror 131 combines the optical path of the light emitted from the first light source unit 111 and the optical path of the light emitted from the second light source unit 112. Specifically, the dichroic mirror 131 has a cutoff wavelength in the vicinity of a wavelength of 520 nm, transmits light having a wavelength shorter than the cutoff wavelength, and reflects light having a wavelength longer than the cutoff wavelength. Yes. Therefore, the purple LED light and the blue fluorescence emitted from the first light source unit 111 are transmitted through the dichroic mirror 131. Further, the yellow fluorescence emitted from the second light source unit 112 is reflected by the dichroic mirror 131. Thereby, the optical path of the light emitted from the first light source unit 111 and the light emitted from the second light source unit 112 is combined. The light whose optical path is synthesized by the dichroic mirror 131 is emitted as the irradiation light L toward the wavelength limiting filter 161.

The wavelength limiting filter 161 has a characteristic of transmitting only light in a specific wavelength band. FIG. 3 shows the spectral transmission characteristic T161 of the wavelength limiting filter 161. The horizontal axis of the graph shown in FIG. 3 indicates the wavelength (nm), and the vertical axis indicates the transmittance. As shown in FIG. 3, the wavelength limiting filter 161 has a transmittance of about 1 (100%) for light in the vicinity of a wavelength of 415 nm and a wavelength of about 550 nm, and has a transmittance of about 0 (0) for light in other wavelength bands. %).

The wavelength limiting filter 161 is supported by the filter insertion / extraction mechanism 171 so that it can be inserted into and removed from the optical path of the irradiation light L. When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 161 is removed from the optical path of the irradiation light L as indicated by a dotted line in FIG. In this case, the irradiation light L is emitted from the light source device 201 without being limited in wavelength by the wavelength limiting filter 161. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 161 is inserted in the optical path of the irradiation light L as indicated by a solid line in FIG. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 201.

FIG. 4 is a block diagram conceptually showing only the light source units 111 and 112, the dichroic mirror 131, and the wavelength limiting filter 161 in the light source device 201. Since the blue phosphor 111b is a separate body from the purple LED 111a, the blue phosphor 111b and the purple LED 111a are shown as separate blocks in FIG. On the other hand, since the yellow phosphor 112b is attached to the light emitting surface of the blue LED 112a and is configured integrally with the blue LED 112a, the yellow phosphor 112b and the blue LED 112a are shown in one block in FIG. Yes.

Further, the dichroic mirror 131 synthesizes optical paths of light having different wavelengths. Therefore, in FIG. 4, the dichroic mirror 131 is indicated by an addition symbol “+”. In FIG. 4, the collimating lenses 121 and 122 disposed in front of the light source units 111 and 112 are omitted.

In FIG. 4, each arrow indicates an optical path of light. In the example shown in FIG. 4, the purple LED light emitted from the purple LED 111a of the first light source unit 111 and the blue fluorescence emitted from the blue phosphor 111b are emitted in the same optical path. Further, the blue LED light emitted from the blue LED of the second light source unit 112 and the yellow fluorescence emitted from the yellow phosphor are emitted in the same optical path. The optical path of the light emitted from the first light source unit 111 and the optical path of the light emitted from the second light source unit 112 are combined by the dichroic mirror 131. The light whose optical path is synthesized by the dichroic mirror 131 is emitted as the irradiation light L from the light source device 201.

As shown in FIG. 1, the irradiation light L emitted from the light source device 201 is condensed on the incident end face of the LCB (Light Carrying Bundle) 11 by the condenser lens 25 and enters the LCB 11.

The irradiation light L incident on the LCB 11 propagates in the LCB 11. The irradiation light L propagating through the LCB 11 is emitted from the emission end surface of the LCB 11 disposed at the tip of the electronic scope 100 and is irradiated onto the subject via the light distribution lens 12. The return light from the subject irradiated with the irradiation light L from the light distribution lens 12 forms an optical image on the light receiving surface of the solid-state imaging device 14 via the objective lens 13.

The solid-state imaging device 14 is a single-plate color CCD (Charge Coupled Device) image sensor having a Bayer pixel arrangement. The solid-state imaging device 14 accumulates an optical image formed by each pixel on the light receiving surface as a charge corresponding to the amount of light, and generates R (Red), G (Green), and B (Blue) image signals. Output. The solid-state imaging device 14 is not limited to a CCD image sensor, and may be replaced with a CMOS (Complementary Metal Oxide Semiconductor) image sensor or other types of imaging devices. The solid-state image sensor 14 may also be one having a complementary color filter mounted thereon.

In the connection part of the electronic scope 100, a driver signal processing circuit 15 is provided. An image signal of a subject irradiated with light from the light distribution lens 12 is input to the driver signal processing circuit 15 from the solid-state imaging device 14 at a frame period. The frame period is, for example, 1/30 seconds. The driver signal processing circuit 15 performs a predetermined process on the image signal input from the solid-state imaging device 14 and outputs the processed image signal to the upstream signal processing circuit 26 of the processor 200.

The driver signal processing circuit 15 also accesses the memory 16 and reads the unique information of the electronic scope 100. The unique information of the electronic scope 100 recorded in the memory 16 includes, for example, the number and sensitivity of the solid-state imaging device 14, an operable frame rate, a model number, and the like. The driver signal processing circuit 15 outputs the unique information read from the memory 16 to the system controller 21.

The system controller 21 performs various calculations based on the unique information of the electronic scope 100 and generates a control signal. The system controller 21 uses the generated control signal to control the operation and timing of various circuits in the processor 200 so that processing suitable for the electronic scope 100 connected to the processor 200 is performed.

The timing controller 22 supplies clock pulses to the driver signal processing circuit 15 according to the timing control by the system controller 21. The driver signal processing circuit 15 drives and controls the solid-state imaging device 14 at a timing synchronized with the frame rate of the video processed on the processor 200 side in accordance with the clock pulse supplied from the timing controller 22.

The pre-stage signal processing circuit 26 performs predetermined signal processing such as demosaic processing, matrix calculation, and Y / C separation on the image signal input from the driver signal processing circuit 15 in one frame period, and outputs it to the image memory 27. To do.

The image memory 27 buffers the image signal input from the upstream signal processing circuit 26 and outputs it to the downstream signal processing circuit 28 according to the timing control by the timing controller 22.

The post-stage signal processing circuit 28 processes the image signal input from the image memory 27 to generate screen data for monitor display, and converts the generated screen data for monitor display into a predetermined video format signal. The converted video format signal is output to the monitor 300. Thereby, the image of the subject is displayed on the display screen of the monitor 300.

The electronic endoscope system 1 of the present embodiment has a plurality of observation modes including a normal observation mode and a special observation mode. Each observation mode is switched manually or automatically depending on the subject to be observed. For example, when it is desired to observe the subject illuminated with normal light, the observation mode is switched to the normal observation mode. The normal light is, for example, white light or pseudo white light. White light has a flat spectral intensity distribution in the visible light band. The pseudo-white light has a spectral intensity distribution that is not flat, and light in a plurality of wavelength bands is mixed. For example, when it is desired to obtain a captured image in which a specific living tissue is emphasized by illuminating the subject with special light, the observation mode is switched to the special observation mode. In addition, special light is light with a high light absorbency with respect to a specific biological tissue, for example. Hereinafter, a case where the biological tissue emphasized in the special observation mode is a surface blood vessel will be described.

血液 Blood containing hemoglobin flows in the surface blood vessels. It is known that hemoglobin has absorbance peaks near wavelengths of 415 nm and 550 nm. Therefore, by irradiating the subject with special light suitable for emphasizing the superficial blood vessels (specifically, light having a higher intensity near the wavelength of 415 nm where the absorbance of hemoglobin is peak than other wavelength bands). A captured image in which the superficial blood vessels are emphasized can be obtained. Further, by irradiating special light having a high intensity near the wavelength of 550 nm, which is another peak of the absorbance of hemoglobin, together with the light near the wavelength of 415 nm, the brightness of the photographed image is maintained while maintaining the state where the surface blood vessels are emphasized. Can be brightened.

FIG. 5 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 201 in each observation mode. 5A shows a spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 5B shows a spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. The horizontal axis of the spectral intensity distribution shown in FIG. 5 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, the first light source unit 111 and the second light source unit 112 are driven to emit light after the blue phosphor 111b is inserted in the optical path. At this time, the wavelength limiting filter 161 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D111 of light emitted from the first light source unit 111 has peaks at a wavelength of about 415 nm and a wavelength of about 470 nm. In the present application, a wavelength having the highest intensity among the specific wavelengths is referred to as a peak wavelength. For example, when there are two or more intensity peaks, the wavelength having the highest intensity is called the peak wavelength. The two wavelengths that are the intensity peaks of the spectral intensity distribution D111 are the peak wavelength of the light emitted from the purple LED 111a and the peak wavelength of the spectral intensity distribution of the fluorescence emitted from the blue phosphor 111b.

The spectral intensity distribution D112 of light emitted from the second light source unit 112 has peaks at a wavelength of about 450 nm and a wavelength of about 600 nm. These two wavelengths are respectively the peak wavelength of the intensity distribution of the light emitted from the blue LED 112a and the peak wavelength of the spectral intensity distribution of the fluorescence emitted from the yellow phosphor 112b.

The spectral intensity distribution D111 shown in FIG. 5A has substantially the same peak intensity of purple LED light and blue fluorescence, but the present invention is not limited to this. The ratio of the intensity of the purple LED light emitted from the first light source unit 111 to the intensity of blue fluorescence can be freely changed by changing the type and amount of use of the blue phosphor 111b. Further, the spectral intensity distribution D112 shown in FIG. 5A has a larger ratio of the intensity of yellow fluorescence than the blue LED light, but the present invention is not limited to this. The ratio between the blue LED light emitted from the second light source unit 112 and the yellow fluorescence can be freely changed by changing the type and amount of use of the yellow phosphor 112b.

In the spectral intensity distributions D111 and D112 shown in FIG. 5A, the maximum intensity is set to 1, but the present invention is not limited to this. The intensity ratio of the light emitted from the light source units 111 and 112 can be arbitrarily set according to the subject to be observed, the photographing mode, and the operator's preference.

Further, in FIG. 5A, the cutoff wavelength λ 131 of the dichroic mirror 131 is indicated by a dotted line. The dichroic mirror 131 has a cutoff wavelength λ131 of about 520 nm, transmits light in a wavelength band shorter than the cutoff wavelength λ131, and reflects light in a wavelength band longer than the cutoff wavelength λ131. Therefore, in the spectral intensity distribution D111 shown in FIG. 5A, light in the wavelength band indicated by the solid line is transmitted through the dichroic mirror 131, and light in the wavelength band indicated by the broken line is reflected by the dichroic mirror 131. Also, in the spectral intensity distribution D112 shown in FIG. 5A, light in the wavelength band equal to or greater than the cutoff wavelength λ131 indicated by the solid line is reflected by the dichroic mirror 131, and the wavelength is longer than the cutoff wavelength λ131 indicated by the broken line. Band light passes through the dichroic mirror 131.

As a result, the optical paths of the light emitted from the light source units 111 and 112 are synthesized by the dichroic mirror 131, and the light source device 201 emits light having a wide wavelength band from the ultraviolet region (part of the near ultraviolet) to the red region. Light L (normal light) is emitted. The spectral intensity distribution of the irradiation light L (normal light) is the sum of the areas indicated by the solid lines in the spectral intensity distributions D111 and D112 shown in FIG.

In the present embodiment, two phosphors 111b and 112b having a wide wavelength band and different wavelength bands are provided. Therefore, the spectral intensity distribution of the irradiation light L (normal light) is closer to flat in the visible light band than when no phosphor is used or when only one type of phosphor is used. Thereby, the subject is illuminated with the irradiation light L (normal light) close to natural white light, and a color photographed image with high color reproducibility can be obtained.

Further, when the electronic endoscope system 1 is in the special observation mode, the first light source unit 111 and the second light source unit 112 are driven to emit light after the blue phosphor 111b is removed from the optical path. At this time, the wavelength limiting filter 161 is inserted on the optical path of the irradiation light L.

FIG. 5B shows the intensity distribution of light emitted from the light source units 111 and 112 and the spectral transmission characteristic T161 of the wavelength limiting filter 161. Light emitted from the light source device 201 as irradiation light L (special light) is light whose optical path is combined by the dichroic mirror 131 and transmitted through the wavelength limiting filter 161. Therefore, the spectral intensity distribution of the irradiation light L (special light) is the sum of the areas indicated by the solid lines in the spectral intensity distributions D111 and D112 shown in FIG.

When the electronic endoscope system 1 is in the special observation mode, since the blue phosphor 111b is removed from the optical path, the light emitted from the purple LED 111a is not used to excite the blue phosphor 111b. It is possible to increase the intensity of light in the vicinity of a wavelength of 415 nm, which is the peak of the absorbance. Also, the wavelength limiting filter 161 irradiates the subject with only light having a wavelength of about 550 nm, which is another peak of hemoglobin absorbance, out of light emitted from the second light source unit 112. Thereby, the brightness | luminance of a picked-up image can be raised, maintaining the state by which the surface blood vessel was emphasized.

Further, the light paths of the light emitted from the light source units 111 and 112 are combined by the dichroic mirror 131. At this time, since the wavelength bands of the light emitted from the light source units 111 and 112 are different from each other, the loss of the light amount can be minimized when the optical paths in the dichroic mirror 131 are combined.

In this embodiment, the spectral intensity distribution of the irradiation light L emitted from the light source device 201 is switched by inserting and extracting the wavelength limiting filter 161 on the optical path of the illumination light L. Thereby, the processor 200 does not need to have the plurality of light source devices 201 in accordance with the spectral intensity distribution of the desired irradiation light L, and the configuration of the processor 200 can be simplified and downsized.

When the electronic endoscope system 1 is in the special observation mode, as shown in FIG. 5 (b), the peak intensities of the spectral intensity distributions D111 and D112 are all set to 1, but the present invention is not limited to this. It is not limited to. For example, in the special observation mode, the second light source unit 112 may be driven to emit light so that the drive current is smaller and the intensity is lower than that in the normal observation mode. As a result, the intensity near the wavelength of 415 nm at which the absorbance of hemoglobin is absorbed is relatively higher than the intensity in other wavelength bands, and a captured image in which the surface blood vessels are emphasized can be obtained.

In the present embodiment, the blue phosphor 111b is supported by the phosphor insertion / extraction mechanism 151 so that it can be inserted into and removed from the optical path. However, the present invention is not limited to this. For example, the blue phosphor 111b is not insertable / removable on the optical path, and may be attached on the light emitting surface of the purple LED 111a. In this case, when the electronic endoscope system 1 is in the special observation mode, blue fluorescence is also emitted from the first light source unit 111. However, since the blue fluorescence is cut by the wavelength limiting filter 161, the enhancement effect of the surface blood vessels is not reduced by the blue fluorescence.

(Second Embodiment)
Next, an endoscope light source device according to a second embodiment of the present invention will be described. The light source device according to the second embodiment is also used in the electronic endoscope system 1 in the same manner as the light source device 201 according to the first embodiment.

FIG. 6 is a block diagram conceptually showing only a light source unit, a dichroic mirror, and a wavelength limiting filter in the light source device 202 according to the second embodiment. The light source device 202 includes a first light source unit 211, a second light source unit 212, a dichroic mirror 231, and a wavelength limiting filter 261. The light source units 211 and 212 are individually controlled to emit light by a first light source drive circuit and a second light source drive circuit (not shown).

The first light source unit 211 has a purple LED 211a that emits light in a purple wavelength band (for example, a wavelength of 395 to 435 nm) and a blue phosphor 211b. The blue phosphor 211b is excited by the purple LED light emitted from the purple LED 211a and emits fluorescence in a blue wavelength band (for example, a wavelength of 430 to 550 nm). The blue phosphor 211b is supported by an unillustrated phosphor insertion / extraction mechanism so that the blue phosphor 211b can be inserted into and removed from the optical path of the purple LED light emitted from the purple LED 211a.

The second light source unit 212 includes a blue LED, a green phosphor, and a red phosphor that emit light in a blue wavelength band (for example, a wavelength of 420 to 480 nm). The green phosphor is excited by blue LED light emitted from the blue LED, and emits fluorescence in a green wavelength band (for example, a wavelength of 510 to 630 nm). The red phosphor is excited by the blue LED light emitted from the blue LED and emits fluorescence in the red wavelength band (for example, the wavelength is 550 to 750 nm). The green phosphor and the red phosphor may be arranged side by side along the emission direction of the blue LED light, or may be arranged side by side in a direction perpendicular to the emission direction of the blue LED light. The green phosphor and the red phosphor may be prepared as a single phosphor by mixing the materials.

A collimating lens (not shown) is arranged in front of the light source units 211 and 212 in the emission direction. The light emitted from the first light source unit 211 is converted into parallel light by the collimator lens and is incident on the dichroic mirror 231. The light emitted from the second light source unit 212 is converted into parallel light by the collimator lens and is incident on the dichroic mirror 231. The dichroic mirror 231 combines the optical path of the light emitted from the first light source unit 211 and the optical path of the light emitted from the second light source unit 212. The light whose optical path is synthesized by the dichroic mirror 231 is emitted as the irradiation light L toward the wavelength limiting filter 261. The spectral transmission characteristic of the wavelength limiting filter 261 is the same as the spectral transmission characteristic of the wavelength limiting filter 161 of the first embodiment.

When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 261 is removed from the optical path of the irradiation light L. In this case, the irradiation light L is emitted from the light source device 202 without the wavelength being limited by the wavelength limiting filter 261. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 261 is inserted in the optical path of the irradiation light L. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 202.

FIG. 7 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 202 in each observation mode. FIG. 7A shows the spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 7B shows the spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. In FIG. 7B, the spectral transmission characteristic T261 of the wavelength limiting filter 261 is also shown. The horizontal axis of the spectral intensity distribution shown in FIG. 7 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, both the first light source unit 211 and the second light source unit 212 are driven to emit light after the blue phosphor 211b is inserted in the optical path. At this time, the wavelength limiting filter 261 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D211 of light emitted from the first light source unit 211 has peaks at a wavelength of about 415 nm and a wavelength of about 470 nm. These two wavelengths are the peak wavelength of the intensity distribution of the light emitted from the purple LED 211a and the peak wavelength of the spectral intensity distribution of the fluorescence emitted from the blue phosphor 211b.

The spectral intensity distribution D212 of light emitted from the second light source unit 212 has peaks at wavelengths of about 450 nm, about 550 nm, and about 650 nm. These three wavelengths are respectively the peak wavelengths of the intensity distribution of the blue LED light, the fluorescence emitted by the green phosphor, and the fluorescence emitted by the red phosphor.

In FIG. 7A, the cutoff wavelength λ231 of the dichroic mirror 231 is indicated by a dotted line. The dichroic mirror 231 has a cutoff wavelength λ231 of about 510 nm, transmits light in a wavelength band shorter than the cutoff wavelength λ231, and reflects light in a wavelength band longer than the cutoff wavelength λ231. Therefore, in the spectral intensity distribution D211 shown in FIG. 7A, light in the wavelength band indicated by the solid line passes through the dichroic mirror 231 and light in the wavelength band indicated by the broken line is reflected by the dichroic mirror 231. In the spectral intensity distribution D212 shown in FIG. 7A, light in the wavelength band indicated by the solid line is reflected by the dichroic mirror 231 and light in the wavelength band indicated by the broken line passes through the dichroic mirror 231.

Thereby, the optical path of the light emitted from each of the light source units 211 and 212 is synthesized by the dichroic mirror 231, and the light source device 202 emits light having a wide wavelength band from the ultraviolet region (part of near ultraviolet) to the red region. Light L (normal light) is emitted. The spectral intensity distribution of the irradiation light L (normal light) is the sum of the areas indicated by the solid lines in the spectral intensity distributions D211 and D212 shown in FIG. By irradiating the subject with the irradiation light L (normal light), a normal color photographed image can be obtained.

Further, when the electronic endoscope system 1 is in the special observation mode, both the first light source unit 211 and the second light source unit 212 are driven to emit light after the blue phosphor 211b is removed from the optical path. . At this time, the wavelength limiting filter 261 is inserted on the optical path of the irradiation light L. As a result, the ratio of light in the vicinity of the wavelength of 415 nm, which is the peak of the absorbance of hemoglobin, in the irradiation light L (special light) is relatively high, and a captured image in which the surface blood vessels are emphasized can be obtained.

The second light source unit 212 has two phosphors, green and red. Therefore, the spectral intensity distribution of the irradiation light L (normal light) when the electronic endoscope system 1 is in the normal observation mode is more visible than when the second light source unit 212 has one phosphor. It approaches flat in the area. Thereby, in the normal observation mode, the subject can be illuminated with the irradiation light L (normal light) close to natural white light.

(Third embodiment)
Next, an endoscope light source device according to a third embodiment of the present invention will be described. The light source device according to the third embodiment is also used in the electronic endoscope system 1 in the same manner as the light source device 201 according to the first embodiment.

FIG. 8 is a block diagram conceptually showing only a light source unit, a dichroic mirror, and a wavelength limiting filter in the light source device 203 according to the third embodiment. The light source device 203 includes a first light source unit 311, a second light source unit 312, a dichroic mirror 331, and a wavelength limiting filter 361. The light source units 311 and 312 are individually controlled to emit light by a first light source drive circuit and a second light source drive circuit (not shown).

The first light source unit 311 is a purple LED that emits light in a purple wavelength band (for example, a wavelength of 395 to 435 nm). The second light source unit 312 includes a phosphor LED 312a and a red phosphor 312b. The phosphor LED 312a includes a blue LED that emits light in a blue wavelength band (for example, a wavelength of 430 to 490 nm), and a green phosphor that is attached on the light emitting surface of the blue LED. This green phosphor is excited by blue LED light emitted from a blue LED, and emits fluorescence in a green wavelength band (for example, a wavelength of 460 to 600 nm). The red phosphor 312b is excited by the blue LED light emitted from the blue LED, and emits fluorescence in the red wavelength band (for example, the wavelength is 550 to 750 nm). The red phosphor 312b is supported by an unillustrated phosphor insertion / extraction mechanism so that the red phosphor 312b can be inserted into and removed from the optical path of light emitted from the blue LED.

A collimator lens (not shown) is arranged in front of the light source units 311 and 312 in the emission direction. The purple LED light emitted from the first light source unit 311 is converted into parallel light by the collimator lens and is incident on the dichroic mirror 331. The light emitted from the second light source unit 312, that is, the blue LED light and the green and red fluorescence are converted into parallel light by the collimator lens and are incident on the dichroic mirror 331. The dichroic mirror 331 combines the optical path of the light emitted from the first light source unit 311 and the optical path of the light emitted from the second light source unit 312. The light whose optical path is synthesized by the dichroic mirror 331 is emitted as irradiation light L toward the wavelength limiting filter 361. The spectral transmission characteristic of the wavelength limiting filter 361 is the same as the spectral transmission characteristic of the wavelength limiting filter 161 of the first embodiment.

When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 361 is removed from the optical path of the irradiation light L. In this case, the irradiation light L is emitted from the light source device 203 without being limited in wavelength by the wavelength limiting filter 361. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 361 is inserted into the optical path of the irradiation light L. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 203.

FIG. 9 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 203 in each observation mode. 9A shows the spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 9B shows the spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. FIG. 9B also shows the spectral transmission characteristic T361 of the wavelength limiting filter 361. The horizontal axis of the spectral intensity distribution shown in FIG. 9 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, both the light source unit 311 and the light source unit 312 are driven to emit light after the red phosphor 312b is inserted in the optical path. At this time, the wavelength limiting filter 361 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D311 of light emitted from the first light source unit 311 has a steep intensity distribution having a peak wavelength of about 415 nm. The spectral intensity distribution D312 of light emitted from the second light source unit 312 has peaks at wavelengths of about 470 nm, about 550 nm, and about 630 nm. These three wavelengths are respectively the peak wavelengths of the intensity distribution of blue LED light, green fluorescence, and red fluorescence.

Further, in FIG. 9A, the cutoff wavelength λ331 of the dichroic mirror 331 is indicated by a dotted line. The dichroic mirror 331 has a cutoff wavelength λ331 of about 430 nm, transmits light in a wavelength band shorter than the cutoff wavelength λ331, and reflects light in a wavelength band greater than or equal to the cutoff wavelength λ331. Therefore, in the spectral intensity distribution D311 shown in FIG. 9A, light in the wavelength band indicated by the solid line passes through the dichroic mirror 331, and light in the wavelength band indicated by the broken line is reflected by the dichroic mirror 331. In the spectral intensity distribution D312 shown in FIG. 9A, light in the wavelength band indicated by the solid line is reflected by the dichroic mirror 331, and light in the wavelength band indicated by the broken line passes through the dichroic mirror 331.

In this way, by combining the optical paths of the light emitted from the light source units 311 and 312 by the dichroic mirror 331, the light source device 203 has a wide wavelength from the ultraviolet region (part of the near ultraviolet) to the red region. Irradiation light L (normal light) having a band is emitted. The spectral intensity distribution of the irradiation light L (normal light) is the sum of the areas indicated by the solid lines in the spectral intensity distributions D311 and D312 shown in FIG. By irradiating the subject with the irradiation light L (normal light), a normal color photographed image can be obtained.

Further, when the electronic endoscope system 1 is in the special observation mode, both the first light source unit 311 and the second light source unit 312 are driven to emit light after the red phosphor 312b is removed from the optical path. . At this time, the wavelength limiting filter 361 is inserted on the optical path of the irradiation light L. As a result, in the irradiation light L (special light), the intensity near the wavelength of 415 nm, which is the peak of the absorbance of hemoglobin, is relatively higher than the intensity of other wavelength bands, and the captured image in which the surface blood vessels are emphasized is obtained. Obtainable.

The second light source unit 312 has two phosphors, green and red. Therefore, the spectral intensity distribution of the irradiation light L (normal light) when the electronic endoscope system 1 is in the normal observation mode is more visible than when the second light source unit 312 has one phosphor. It approaches flat in the area. Accordingly, the subject can be illuminated with the irradiation light L (normal light) close to natural white light.

In the present embodiment, the red phosphor 312b is supported by the phosphor insertion / removal mechanism so that it can be inserted / removed on the optical path, but the present invention is not limited to this. For example, the red phosphor 312b is not insertable / removable on the optical path, and may be attached together with the green LED on the light emitting surface of the blue LED. In this case, when the electronic endoscope system 1 is in the special observation mode, red fluorescence is also emitted from the second light source unit 312. However, since the red fluorescence is cut by the wavelength limiting filter 361, the enhancement effect of the surface blood vessels is not reduced by the red fluorescence.

(Fourth embodiment)
FIG. 10 is a block diagram conceptually showing only the light source unit, the dichroic mirror, and the wavelength limiting filter in the light source device 204 according to the fourth embodiment of the present invention. Similarly to the light source device 201 according to the first embodiment, the light source device 204 according to the fourth embodiment is used in the electronic endoscope system 1, for example.

As shown in FIG. 10, the light source device 204 includes first to third light source units 411 to 413, first and second dichroic mirrors 431 and 432, and a wavelength limiting filter 461. The light source units 411 to 413 are individually controlled to emit light by first to third light source driving circuits (not shown).

The first light source unit 411 emits light in a purple wavelength band (for example, a wavelength of 395 to 435 nm) and is excited by the purple LED light to emit blue (for example, a wavelength of 430 to 490 nm) fluorescence. It has a blue phosphor that emits light. The second light source unit 412 is excited by a blue LED that emits light in a blue wavelength band (for example, a wavelength of 430 to 470 nm) and a blue LED light emitted from the blue LED, and a yellow wavelength band (for example, It has a yellow phosphor that emits fluorescence having a wavelength of 500 to 720 nm. The third light source unit 413 is a red LED that emits light in a red wavelength band (for example, a wavelength of 620 to 680 nm).

A collimator lens (not shown) is arranged in front of each of the light source units 411 to 413 in the emission direction. Purple LED light and blue fluorescence emitted from the first light source unit 411 are converted into parallel light by a collimating lens and are incident on a dichroic mirror 431. Further, the blue LED light and the yellow fluorescence emitted from the second light source unit 412 are converted into parallel light by the collimator lens and are incident on the dichroic mirror 431. The dichroic mirror 431 combines the optical path of the light emitted from the first light source unit 411 and the optical path of the light emitted from the second light source unit 412. The light whose optical path is synthesized by the dichroic mirror 431 enters the dichroic mirror 432.

Also, the red LED light emitted from the third light source unit 413 is converted into parallel light by the collimating lens and is incident on the dichroic mirror 432. The dichroic mirror 432 combines the optical path of the light incident from the dichroic mirror 431 and the optical path of the light emitted from the third light source unit 413. The light whose optical path is synthesized by the dichroic mirror 432 is emitted as irradiation light L toward the wavelength limiting filter 461. The spectral transmission characteristic of the wavelength limiting filter 461 is the same as the spectral transmission characteristic of the wavelength limiting filter 161 of the first embodiment.

When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 461 is removed from the optical path of the irradiation light L. In this case, the irradiation light L is emitted from the light source device 204 without being limited in wavelength by the wavelength limiting filter 461. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 461 is inserted in the optical path of the irradiation light L. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 204.

FIG. 11 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 204 in each observation mode. FIG. 11A shows the spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 11B shows the spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. FIG. 11B also shows the spectral transmission characteristic T461 of the wavelength limiting filter 461. The horizontal axis of the spectral intensity distribution shown in FIG. 11 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, the first to third light source units 411 to 413 are all driven to emit light. At this time, the wavelength limiting filter 461 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D411 of the first light source unit 411 has peaks at wavelengths of about 415 nm and 470 nm. These two wavelengths are the peak wavelengths of purple LED light and blue fluorescence, respectively. Here, in the spectral intensity distribution D411, the height of the peak at the wavelength of about 415 nm is set to be higher than the height of the peak at the wavelength of about 470 nm. The spectral intensity distribution D412 of the second light source unit 412 has peaks at about 450 nm and 600 nm. These two wavelengths are the peak wavelengths of blue LED light and yellow fluorescence, respectively. The spectral intensity distribution D413 of the third light source unit 413 has a steep intensity distribution having a peak wavelength of about 650 nm.

In FIG. 11A, the cutoff wavelengths λ431 and λ432 of the dichroic mirrors 431 and 432 are indicated by dotted lines. Cutoff wavelengths λ431 and λ432 are 520 nm and 630 nm, respectively. Any of the dichroic mirrors 431 and 432 transmits light having a wavelength band shorter than the cutoff wavelength, and reflects light having a wavelength band equal to or greater than the cutoff wavelength. By the dichroic mirrors 431 and 432, the optical paths of the light emitted from the light source units 411 to 413 are combined. Of the light emitted from the second light source unit 412, the blue LED light having a peak wavelength of about 450 nm is shorter than the cutoff wavelength λ431, and thus is included in the light whose optical path is synthesized by the dichroic mirror 431. I can't.

As described above, the light paths emitted from the respective light source units 411 to 413 are synthesized by the dichroic mirrors 431 and 432, so that the light source device 204 can emit light from the ultraviolet region (part of near ultraviolet) to the red region. Irradiation light L (normal light) having a wide wavelength band is emitted. The spectral intensity distribution of the irradiation light L (normal light) is the sum of the areas indicated by the solid lines in the spectral intensity distributions D411 to D413 shown in FIG. By irradiating the subject with the irradiation light L (normal light), a normal color photographed image can be obtained.

In addition, when the electronic endoscope system 1 is in the special observation mode, the first light source unit 411 and the second light source unit 412 are driven to emit light, and the third light source unit 413 is not driven to emit light. At this time, the wavelength limiting filter 461 is inserted on the optical path of the irradiation light L. As a result, in the irradiation light L (special light), the intensity around the wavelength of 415 nm at which the absorbance of hemoglobin is absorbed is relatively higher than the intensity in other wavelength bands, and a captured image in which the surface blood vessels are emphasized is obtained. Obtainable.

In addition, the biological tissue in the body cavity imaged by the electronic endoscope system 1 is generally reddish due to blood. For this reason, when red light is irradiated onto the living tissue in the special observation mode, the entire captured image is reddish, and it is difficult to obtain an effect of enhancing the superficial blood vessels. In the present embodiment, since the red LED (third light source unit 413) is not driven to emit light in the special observation mode, it is possible to prevent the enhancement effect of the superficial blood vessels from being reduced.

In the fourth embodiment, the second light source unit 412 has a yellow phosphor, but the present invention is not limited to this. For example, the second light source unit 412 may include a green phosphor having a peak wavelength near 550 nm, instead of the yellow phosphor.

(Fifth embodiment)
Next, an endoscope light source device according to a fifth embodiment of the present invention will be described. The light source device according to the fifth embodiment is also used in the electronic endoscope system 1 in the same manner as the light source device 201 according to the first embodiment.

FIG. 12 is a block diagram conceptually showing only a light source unit, a dichroic mirror, and a wavelength limiting filter in the light source device 205 according to the fifth embodiment. The light source device 205 includes a first light source unit 511, a second light source unit 512, a dichroic mirror 531, and a wavelength limiting filter 561. The light source units 511 and 512 are individually controlled to emit light by first and second light source driving circuits (not shown).

The first light source unit 511 includes a purple LED that emits light in a purple wavelength band (for example, a wavelength of 395 to 435 nm), and a green phosphor and a blue phosphor that are mounted on the light emitting surface of the purple LED. ing. The green phosphor is excited by the purple LED light emitted from the purple LED, and emits fluorescence in the green wavelength band (for example, the wavelength is 510 to 630 nm). The blue phosphor is excited by the violet LED light emitted from the violet LED, and emits fluorescence in a blue wavelength band (for example, the wavelength is 430 to 550 nm).

The second light source unit 512 is a red LED that emits light in a red wavelength band (for example, a wavelength of 620 to 680 nm). The dichroic mirror 531 combines the optical path of the light emitted from the first light source unit 511 and the optical path of the light emitted from the second light source unit 512. The light whose optical path is synthesized by the dichroic mirror 531 is emitted toward the wavelength limiting filter 561 as the irradiation light L. The spectral transmission characteristic of the wavelength limiting filter 561 is the same as the spectral transmission characteristic of the wavelength limiting filter 161 of the first embodiment.

When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 561 is removed from the optical path of the irradiation light L. In this case, the irradiation light L is emitted from the light source device 205 without the wavelength being limited by the wavelength limiting filter 561. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 561 is inserted in the optical path of the irradiation light L. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 205.

FIG. 13 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 205 in each observation mode. 13A shows the spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 13B shows the spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. FIG. 13B also shows the spectral transmission characteristic T561 of the wavelength limiting filter 561. The horizontal axis of the spectral intensity distribution shown in FIG. 13 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, the first and second light source units 511 and 512 are driven to emit light. At this time, the wavelength limiting filter 561 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D511 of light emitted from the first light source unit 511 has peaks at wavelengths of about 415 nm, about 470 nm, and about 550 nm. These three wavelengths are respectively the peak wavelengths of the purple LED light emitted from the purple LED, the fluorescence emitted by the blue phosphor, and the fluorescence emitted by the green phosphor. The spectral intensity distribution D512 of light emitted from the second light source unit 512 has an intensity distribution with a peak wavelength of about 650 nm.

In FIG. 13A, the cutoff wavelength λ 531 of the dichroic mirror 531 is indicated by a dotted line. The cutoff wavelength λ531 is 620 nm. The dichroic mirror 531 transmits light in a wavelength band shorter than the cutoff wavelength, and reflects light in a wavelength band equal to or greater than the cutoff wavelength. By this dichroic mirror 531, the optical paths of the light emitted from the first light source unit 511 and the second light source unit 512 are combined and emitted as irradiation light L. By irradiating the subject with the irradiation light L (normal light), a normal color photographed image can be obtained.

Further, when the electronic endoscope system 1 is in the special observation mode, only the first light source unit 511 is driven to emit light, and the second light source unit 512 is not driven to emit light. At this time, the wavelength limiting filter 561 is inserted on the optical path of the irradiation light L. As a result, the ratio of light in the vicinity of the wavelength of 415 nm, which is the peak of the absorbance of hemoglobin, in the irradiation light L (special light) is relatively high, and a captured image in which the surface blood vessels are emphasized can be obtained.

(Sixth embodiment)
Next, an endoscope light source device according to a sixth embodiment of the present invention will be described. The light source device according to the sixth embodiment is also used in the electronic endoscope system 1 in the same manner as the light source device 201 according to the first embodiment.

FIG. 14 is a block diagram conceptually showing only the light source unit and the wavelength limiting filter in the light source device 206 according to the sixth embodiment. The light source device 206 includes a light source unit 611 and a wavelength limiting filter 661. The light source unit 611 is controlled to emit light by a light source driving circuit (not shown).

The light source unit 611 includes a purple LED, a blue phosphor, a green phosphor, and a red phosphor that emit light in a purple wavelength band (for example, a wavelength of 395 to 435 nm). The blue phosphor is excited by the violet LED light emitted from the violet LED, and emits fluorescence in a blue wavelength band (for example, the wavelength is 430 to 550 nm). The green phosphor is excited by the purple LED light emitted from the purple LED, and emits fluorescence in the green wavelength band (for example, the wavelength is 510 to 630 nm). The red phosphor is excited by the violet LED light emitted from the violet LED, and emits fluorescence in a red wavelength band (for example, the wavelength is 550 to 750 nm). The light emitted from the light source unit 611 is emitted toward the wavelength limiting filter 661 as the irradiation light L. The spectral transmission characteristic of the wavelength limiting filter 661 is the same as the spectral transmission characteristic of the wavelength limiting filter 161 of the first embodiment.

When the electronic endoscope system 1 is in the normal observation mode, the wavelength limiting filter 661 is removed from the optical path of the irradiation light L. In this case, the irradiation light L is emitted from the light source device 206 without being limited in wavelength by the wavelength limiting filter 661. On the other hand, when the electronic endoscope system 1 is in the special observation mode, the wavelength limiting filter 661 is inserted into the optical path of the irradiation light L. In this case, of the irradiation light L, only light having a wavelength near 415 nm and a wavelength near 550 nm is emitted from the light source device 205.

FIG. 15 shows the spectral intensity distribution of the irradiation light L emitted from the light source device 206 in each observation mode. FIG. 15A shows the spectral intensity distribution of the irradiation light L (normal light) in the normal observation mode, and FIG. 15B shows the spectral intensity distribution of the irradiation light L (special light) in the special observation mode. Yes. FIG. 15B also shows the spectral transmission characteristic T661 of the wavelength limiting filter 661. The horizontal axis of the spectral intensity distribution shown in FIG. 15 indicates the wavelength (nm), and the vertical axis indicates the intensity of the irradiation light L. Note that the vertical axis is standardized so that the maximum intensity value is 1.

When the electronic endoscope system 1 is in the normal observation mode, the light source unit 611 is driven to emit light after the wavelength limiting filter 661 is removed from the optical path of the irradiation light L.

The spectral intensity distribution D611 of light emitted from the light source unit 611 has peaks at wavelengths of about 415 nm, about 470 nm, about 550 nm, and about 650 nm. These four wavelengths are the peak wavelengths of the purple LED light emitted from the purple LED, the fluorescence emitted by the blue phosphor, the fluorescence emitted by the green phosphor, and the fluorescence emitted by the red phosphor. The light emitted from the light source unit 611 is irradiated to the subject as irradiation light L (normal light). Thereby, a normal color photographed image can be obtained.

When the electronic endoscope system 1 is in the special observation mode, the light source unit 611 is driven to emit light after the wavelength limiting filter 661 is inserted in the optical path of the irradiation light L. As a result, the ratio of light in the vicinity of the wavelength of 415 nm, which is the peak of the absorbance of hemoglobin, in the irradiation light L (special light) is relatively high, and a captured image in which the surface blood vessels are emphasized can be obtained.

This completes the description of the exemplary embodiment of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of the present invention. For example, the embodiment of the present invention also includes contents appropriately combined with embodiments or the like clearly shown in the specification or obvious embodiments. For example, in each of the above embodiments, an LED is assumed as the solid state light emitting device. The present invention is not limited to this, and it is also possible to employ LD (Laser Diode) as a solid state light emitting device.

Claims (8)

1. A first solid-state light-emitting element, first and second phosphors, a first wavelength band emitted from the first solid-state light-emitting element; a first light emitted from the first phosphor; A light source unit that emits illumination light including fluorescence and second fluorescence emitted from the second phosphor and having a peak wavelength different from the peak wavelength of the first fluorescence;
   A wavelength limiting filter that transmits only light in a specific wavelength band of the illumination light; and
   Filter insertion / extraction means for supporting the wavelength limiting filter so as to be insertable / removable with respect to the optical path of the illumination light,
   With
   When the wavelength limiting filter is inserted into the optical path of the illumination light by the filter insertion / extraction means, the illumination light is filtered into the light containing the first wavelength band and the light containing the second fluorescence, and the endoscope Supplied to
   When the wavelength limiting filter is extracted from the optical path of the illumination light by the filter insertion / extraction means, the illumination light is supplied to the endoscope without being filtered by the wavelength limiting filter,
   Endoscope light source device.
2. The light source unit is
   A second solid state light emitting device;
   The illumination light is
   Further comprising light of a second wavelength band emitted from the second solid state light emitting device,
   The endoscope light source device according to claim 1.
3. The light source unit is
   It further has an excitation solid-state light emitting element that emits excitation light,
   The first phosphor is
   Excited by light of the first wavelength band emitted from the first solid state light emitting device,
   The second phosphor is
   Excited by the excitation light emitted from the excitation solid-state light emitting device,
   The endoscope light source device according to claim 1 or 2.
4. The first phosphor and the second phosphor are:
   Excited by light in the first wavelength band emitted from the first solid state light emitting device.
   The endoscope light source device according to claim 2.
5. The first phosphor and the second phosphor are:
   Excited by light of the second wavelength band emitted from the second solid state light emitting device,
   The endoscope light source device according to claim 2.
6. The light source unit is
   A third phosphor that emits a third fluorescence having a peak wavelength different from the peak wavelength of the first fluorescence and the peak wavelength of the second fluorescence;
   The illumination light is
   Further comprising the third fluorescence,
   The endoscope light source device according to claim 1.
7. The light source unit is
   A first light source unit having the first solid state light emitting device and the first phosphor;
   A second light source unit having the second phosphor;
   Optical path combining means for supplying the illumination light to the endoscope by combining the optical path of the light emitted from the first light source unit and the optical path of the light emitted from the second light source unit;
   Further comprising
   The endoscope light source device according to any one of claims 1 to 3.
8. The first light source unit is
   A phosphor insertion / extraction means for supporting the first phosphor so as to be insertable / removable with respect to an optical path of light emitted from the first solid state light emitting device;
   When the wavelength limiting filter is inserted into the optical path of the illumination light by the filter insertion / extraction means, the phosphor insertion / extraction means extracts the first phosphor from the optical path of the light emitted from the first solid state light emitting device. And
   When the wavelength limiting filter is removed from the optical path of the illumination light by the filter insertion / extraction means, the phosphor insertion / extraction means inserts the first phosphor into the optical path of light emitted from the first solid state light emitting device. To
   The endoscope light source device according to any one of claims 1 to 3 or claim 7.

Images