Endoscopic Devices

Abstract

To acquire desired information of a biological tissue in a further clear state suited for a diagnosis when observing the biological tissue by white light and special light.SOLUTION: An endoscope apparatus includes: a first light source 51 defining a semiconductor light-emitting element as a light-emitting source; a second light source 53 defining a semiconductor light-emitting element having a different light emission wavelength from that of the first light source 51, as a light-emitting source; a wavelength conversion member 57 excitingly emitting light by outgoing light from at least one of the first light source 51 and the second light source 53; and light quantity rate change means 55 for changing a light quantity rate of the outgoing light from the first light source 51 and the outgoing light from the second light source 53. The endoscope apparatus optionally generates the outgoing light from the first light source 51 and the outgoing light from the second light source 53 to provide illumination light suited for the diagnosis according to absorption characteristics and scatter characteristics of a biological tissue. This configuration can thus acquire desired tissue information of the biological tissue in a further clear state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention provides Endoscopic Devices Regarding. [Background technology]

[0002] In a typical endoscope, light from a lamp in a light source device is guided to the tip of the endoscope through a light guide installed inside the endoscope's insertion tube, which is inserted into the subject, and then emitted from an illumination window at the tip to illuminate the subject's observation area. While white light is typically used for observing biological tissue, in recent years, endoscopes capable of special light observation, such as irradiating biological tissue with light of a specific narrow-band wavelength to highlight the state of mucosal tissue or observing autofluorescence from pre-administered fluorescent substances, have been utilized (Patent Documents 1 and 2). By irradiating biological tissue with special light, these types of endoscopes enable observation of, for example, neovascularization occurring in the mucosal layer or submucosal layer, and enable depiction of the fine structure of the mucosal surface, which cannot be obtained with conventional observation images.

[0003] In the above Patent Documents 1 and 2, only a specific wavelength band is extracted from the light emitted from a white light source such as a xenon lamp using a color filter, and the light is used as special light. Note that, in addition to xenon lamps, laser light sources can also be used as white light sources, and for example, a light-emitting device that generates white light by combining a blue laser light source with a phosphor that is excited and emits light using the blue laser as excitation light has been proposed (Patent Document 3).

[0004] However, in the endoscope devices of Patent Documents 1 and 2, light from a white light source is time-divided using color filters, and light of different wavelength bands (e.g., R, G, B light) is emitted in a frame-sequential manner. Therefore, to obtain a full-color observation image, multiple frames (R, G, B) of captured images must be synthesized, which hinders increasing the frame rate of the observation image. Furthermore, because illumination light is generated by absorbing light using color filters, a decrease in the amount of light is unavoidable, which increases the noise component of the observation image. While it is possible to increase sensitivity by lowering the frame rate, this makes the image more susceptible to blurring.

[0005] On the other hand, in special optical diagnosis, tissue information from the superficial and deep layers of biological tissue is an important observation target. For example, in gastrointestinal cancer, tumor blood vessels appear in the superficial layers of the mucosa early on, and compared to normal blood vessels visible in the superficial layers, tumor blood vessels are observed to be dilated, tortuous, and have increased vascular density. Therefore, by carefully examining the characteristics of the blood vessels, it is possible to differentiate the type of tumor. However, with endoscopic devices using the above-mentioned color filters, it is difficult to limit the transmission wavelength band of the color filter to a specific narrow band when observing tissue information, especially in the superficial layers of biological tissue. Moreover, illumination light limited to a narrow band does not provide sufficient light intensity, which has the disadvantage of causing deterioration in the quality of the observed image. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3583731 [Patent Document 2] Special Publication No. 6-40174 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-173324 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention makes it possible to obtain desired tissue information of a living tissue in a clearer state suitable for diagnosis when observing the living tissue with white light or special light. Endoscopic Devices The purpose is to provide the following. [Means for solving the problem]

[0008] The present invention comprises the following configurations. an endoscope having an endoscope insertion section and an operation section; Multiple from semiconductor light emitting devices Illumination using emitted light from the distal end side of the endoscope insertion part, and outputs an observation image of the observation area. And, violet Semiconductor light emitting device and, a first semiconductor light emitting element that emits light with a wavelength longer than that of the violet semiconductor light emitting element; Semiconductor light emitting device and, a second semiconductor light emitting element that emits light with a longer wavelength than the first semiconductor light emitting element; a light intensity ratio setting means for sequentially setting a light intensity ratio between the light emitted from the violet semiconductor light emitting element, the light emitted from the first semiconductor light emitting element, and the light emitted from the second semiconductor light emitting element to a plurality of different preset ratios each time a user operates the light intensity ratio; an imaging element mounted in the endoscope insertion section, which captures light reflected from the observation region irradiated with the illumination light and outputs an image signal of an observation image including blood vessel information; a light source control unit that controls the amount of light emitted from the purple semiconductor light emitting element, the amount of light emitted from the first semiconductor light emitting element, and the amount of light emitted from the second semiconductor light emitting element by pulse modulation control that controls drive waveforms of the purple semiconductor light emitting element, the first semiconductor light emitting element, and the second semiconductor light emitting element within one frame of the image signal of the image sensor based on the light amount ratio set by the light amount ratio setting unit, and that switches and lights up the purple semiconductor light emitting element, the first semiconductor light emitting element, and the second semiconductor light emitting element on a frame-by-frame basis; an image processing unit that performs image calculations using the image signal obtained in a frame in which the violet semiconductor light emitting element is lit, the image signal obtained in a frame in which the first semiconductor light emitting element is lit, and the image signal obtained in a frame in which the second semiconductor light emitting element is lit; An endoscope apparatus comprising: [Effects of the Invention]

[0009] The present invention Endoscopic Devices According to the present invention, when observing biological tissue using white light or special light in a specific wavelength band, desired tissue information of the biological tissue can be obtained in a clearer state suitable for diagnosis. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of an endoscope apparatus using a light source device for an endoscope for explaining an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram illustrating the configuration of the endoscope apparatus shown in FIG. [Figure 3] 1 is a graph showing the emission spectra of laser light from a violet laser light source, blue laser light from a blue laser light source, and light after the blue laser light has been wavelength-converted by a phosphor. [Figure 4] FIG. 2 is a detailed block diagram of an image processing unit. [Figure 5] FIG. 1 is an explanatory diagram showing a schematic diagram of blood vessels in the mucosal surface layer of biological tissue. [Figure 6] FIG. 1 is an explanatory diagram showing a schematic display example of an observation image obtained by an endoscope device. [Figure 7a] This is a magnified image of the inside of the lip observed using an endoscope under white light. [Figure 7b] This is a magnified image of the inside of the lip observed with an endoscopic device at a light intensity ratio of 50:50. [Figure 7c] This is a magnified image of the inside of the lip observed using an endoscopic device with a light intensity ratio of 75:25. [Figure 8] 3 is an explanatory diagram showing an example of a display screen of a display unit that displays an observed image by the endoscope device. FIG. [Figure 9] 10 is an explanatory diagram showing another example of the display screen of the display unit that displays an observed image by the endoscope device. FIG. [Figure 10] 10 is a graph showing the relationship between the current applied to the light source and the amount of light emitted. [Figure 11] 10 is a graph showing a pulse current superimposed waveform of an applied current. [Figure 12] 1A, 1B, and 1C are explanatory diagrams showing various drive waveforms under pulse modulation control. [Figure 13] 10 is a graph showing an example of control in which the light emission amounts of the light sources are alternately maximized. [Figure 14] 1 is a graph showing a schematic relationship between the absorption wavelength band of hemoglobin and the emission wavelength of each light source. [Figure 15] FIG. 10 is an explanatory diagram showing the outline of the image displayed on the display unit when an endoscope operator moves the endoscope insertion portion inside the subject, performs observation using narrowband light at a desired observation position, and then moves it to the next observation position. [Figure 16] 10 is an explanatory diagram showing an example in which a normal image and a narrowband light image are simultaneously displayed by arranging them in separate regions within the same screen. FIG. [Figure 17] 10A and 10B are explanatory diagrams showing an example in which a narrowband light image of a desired range is superimposed on a normal image and simultaneously displayed. [Figure 18] FIG. 10 is an explanatory diagram showing a light intensity ratio table in which light intensity ratios for endoscope operators are registered. [Figure 19] 10 is an explanatory diagram showing an example of displaying a preset light amount ratio on a display unit. FIG. [Figure 20] FIG. 4 is an explanatory diagram of the operation of the changeover switch. [Figure 21] FIG. 10 is an explanatory diagram showing a color conversion coefficient table for a light amount ratio. [Figure 22] 1 is a graph showing the absorption spectra of hemoglobin Hb with a low oxygen concentration and oxygen-saturated oxyhemoglobin HbO2. [Figure 23] 1 is a block diagram showing an example of the configuration of a light source device equipped with a plurality of laser light sources and an endoscope. [Figure 24]FIG. 1 is a block diagram showing an example of the configuration of a light source device and an endoscope in which optical paths are integrated. [Figure 25] 25 is a graph showing an example of an emission spectrum of the light source device and phosphor shown in FIG. 24. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of an endoscope apparatus using a light source device for an endoscope for explaining an embodiment of the present invention, and FIG. 2 is a block diagram of the endoscope apparatus shown in FIG. 1 includes an endoscope 11 and a control device 13 connected to the endoscope 11. A display unit 15 that displays image information and the like, and an input unit 17 that accepts input operations are connected to the control device 13. The endoscope 11 is an electronic endoscope that includes an illumination optical system that emits illumination light from the tip of an endoscope insertion portion 19, and an imaging optical system that includes an imaging element that images the region to be observed.

[0012] The endoscope 11 includes an endoscope insertion section 19 that is inserted into the subject, an operation section 23 that performs operations such as bending the tip of the endoscope insertion section 19 and performing suction, air supply, and water supply from the tip of the endoscope insertion section 19, a connector section 25 that detachably connects the endoscope 11 to the control device 13, and a universal cord section 27 that connects the operation section 23 and the connector section 25. Although not shown, various channels are provided inside the endoscope 11, such as a forceps channel for inserting a tissue sampling treatment tool and the like, and channels for air and water supply.

[0013] The endoscope insertion section 19 is composed of a flexible soft section 31, a bending section 33, and a tip section (hereinafter also referred to as the endoscope tip section) 35. The endoscope tip section 35 is provided with irradiation ports 37A and 37B that irradiate the observation area with light, and an imaging element 21 such as a CCD (charge coupled device) image sensor or a CMOS (complementary metal-oxide semiconductor) image sensor that acquires image information of the observation area. An imaging member 39 such as an objective lens is attached to the imaging element 21.

[0014] The bending section 33 is provided between the flexible section 31 and the tip section 35, and can be bent freely by wire manipulation from the operation section 23, actuator operation, etc. This bending section 33 can be bent in any direction and at any angle depending on the part of the subject on which the endoscope 11 is used, etc., and the observation direction of the irradiation ports 37A, 37B of the endoscope tip section 35 and the image sensor 21 can be directed to the desired observation part. Furthermore, although not shown, a cover glass or a lens is disposed in the irradiation ports 37A, 37B of the endoscope insertion section 19.

[0015] The control device 13 includes a light source device 41 that generates illumination light to be supplied to the irradiation ports 37A and 37B of the endoscope tip 35, and a processor 43 that performs image processing on the image signal from the image sensor 21, and is connected to the display unit 15 and input unit 17. The processor 43 performs image processing on the image signal transmitted from the endoscope 11 based on instructions from the operation unit 23 of the endoscope 11 and the input unit 17, and generates and supplies an image to be displayed to the display unit 15.

[0016] Optical fibers 45A and 45B for introducing illumination light from the light source device 41 and a scope cable 47 connecting the image pickup element 21 and the processor 43 are inserted inside the endoscope 11. Although not shown, various signal lines from the operation unit 23 and tubes such as air and water supply channels are also connected to the control device 13 and the like via the universal cord unit 27 and the connector unit 25. This connector 25 on the endoscope 11 side is detachably connected to connector units 26A and 26B provided on the light source device 41 and the processor 43, respectively, as shown in FIG.

[0017] 2, light source device 41 includes, as light sources, a blue laser light source (first light source) 51 with a central wavelength of 445 nm and a violet laser light source (second light source) 53 with a central wavelength of 405 nm. Light emitted from the semiconductor light-emitting elements of light sources 51 and 53 is individually controlled by light source control unit 55, and the light intensity ratio between the light emitted from blue laser light source 51 and the light emitted from violet laser light source 53 is freely changeable.

[0018] A broad-area InGaN laser diode can be used for the blue laser light source 51, which is the first light source, and the violet laser light source 53, which is the second light source. Alternatively, an InGaNAs laser diode or a GaNAs laser diode can be used. Furthermore, the light sources may be configured to use light emitters such as light-emitting diodes.

[0019] The laser light emitted from each of these light sources 51, 53 is input into an optical fiber by a condenser lens (not shown) and propagates through connector portion 26A and connector 25 (see FIG. 1) on the endoscope 11 side to endoscope tip portion 35 (see FIG. 1) of endoscope 11 by optical fibers 45A, 45B. The laser light from blue laser light source 51 is irradiated onto phosphor 57, which is a wavelength conversion member arranged in endoscope tip portion 35, and the laser light from violet laser light source 53 is irradiated onto light deflection / diffusion member 59.

[0020] The optical fibers 45A and 45B are multimode fibers, and as an example, a small diameter cable with a core diameter of 105 μm, a cladding diameter of 125 μm, and a diameter of 0.3 to 0.5 mm including a protective layer serving as an outer covering can be used.

[0021] The phosphor 57 is made of a plurality of types of phosphors (for example, YAG phosphors or BAM (BaMgAl)) that absorb part of the blue laser light from the blue laser light source 51 and emit light in a range of green to yellow when excited. 10 O 17 ) and the like). As a result, green to yellow excitation light, which uses blue laser light from the blue laser light source 51 as excitation light, and the blue laser light that is not absorbed by the phosphor 57 and is transmitted through the phosphor 57 are combined to produce white (quasi-white) illumination light. If a semiconductor light-emitting element is used as the excitation light source as in this configuration example, high-intensity white light can be obtained with high luminous efficiency, and the intensity of the white light can be easily adjusted. Moreover, changes in the color temperature and chromaticity of the white light are reduced.

[0022] The blue laser light source 51, the phosphor 57, and the optical fiber 45A connecting them may be, for example, "Micro White" (product name) manufactured by Nichia Corporation.

[0023] Furthermore, light deflection / diffusion member 59 may be made of any material that transmits the laser light from violet laser light source 53, such as a light-transmitting resin material or glass. Furthermore, light deflection / diffusion member 59 may be made of a resin material or glass surface on which a light diffusion layer containing minute irregularities or particles (fillers, etc.) with different refractive indices is provided, or may be made of a translucent material. As a result, the transmitted light emitted from light deflection / diffusion member 59 becomes illumination light with a narrow wavelength band in which the amount of light is uniform within a predetermined irradiation area.

[0024] The phosphor 57 and light deflection / diffusion member 59 can prevent phenomena such as superimposition of noise that interferes with imaging and flickering when displaying moving images, which are caused by speckles generated by the coherence of laser light. Furthermore, taking into consideration the difference in refractive index between the fluorescent substance that makes up the phosphor and the fixing / solidifying resin that serves as the filler, it is preferable that the particle size of the fluorescent substance itself and the filler be made of a material that has low absorption and high scattering for light in the infrared range. This enhances the scattering effect without reducing the light intensity of red and infrared light, eliminates the need for optical path changing means such as a concave lens, and reduces optical loss.

[0025] 3 is a graph showing the emission spectra of laser light from violet laser light source 53, blue laser light from blue laser light source 51, and light after the blue laser light has been wavelength-converted by phosphor 57. The violet laser light from violet laser light source 53 is represented by an emission line with a central wavelength of 405 nm (profile A). The blue laser light from blue laser light source 51 is represented by an emission line with a central wavelength of 445 nm, and the excited emission light from phosphor 57 by the blue laser light has a spectral intensity distribution in which the emission intensity increases in the wavelength band of approximately 450 nm to 700 nm (profile B). The above-mentioned white light is formed by profile B of this excited emission light and the blue laser light.

[0026] Here, the white light referred to in this specification is not limited to light that strictly includes all wavelength components of visible light, but may include light in a specific wavelength band, such as R, G, or B, and is broadly intended to include, for example, light that includes wavelength components from green to red, or light that includes wavelength components from blue to green, etc.

[0027] That is, in this endoscope device 100, illumination light is generated by relatively increasing or decreasing the emission intensity of profile A and profile B, so illumination light with different characteristics can be obtained depending on the mixture ratio of profiles A and B.

[0028] Returning to Figure 2 for further explanation, the illumination light formed by the blue laser light source 51, phosphor 57, and violet laser light source 53 as described above is irradiated from the tip of the endoscope 11 toward the observation area of ​​the subject. Then, an image of the observation area irradiated with the illumination light is formed on the imaging element 21 by the imaging lens 61, and an image is taken.

[0029] After capturing an image, the image signal output from the image sensor 21 is converted into a digital signal by an A / D converter 63 and input to an image processing unit 65 of the processor 43. The image processing unit 65 converts the input image signal into image data and performs appropriate image processing to generate desired image information for output. The obtained image information is then displayed on the display unit 15 as an endoscopic observation image via a control unit 67. If necessary, the image information is also recorded in a recording device 69, which is made up of a memory or a storage device.

[0030] The recording device 69 may be built into the processor 43 or may be connected to the processor 43 via a network. Information about the endoscopic observation image recorded in the recording device 69 also records information about the light intensity ratio at the time of capture. This allows accurate interpretation of the recorded endoscopic observation image after endoscopic observation, and also allows appropriate image processing such as image standardization to be performed according to the light intensity ratio, thereby expanding the range of uses for the endoscopic observation image. In particular, if spectral reflectance estimation is performed by pseudo-increasing the number of bands (R, G, B) based on information from multiple images with different spectral light intensity ratios, it becomes possible to separate even subtler color differences.

[0031] A detailed block diagram of the image processing unit is shown in Figure 4. The image signal from the image sensor 21 that is input to the image processing unit 65 is first input to the luminance calculation unit 65a. The luminance calculation unit 65a calculates luminance information such as the maximum luminance, minimum luminance, and average screen luminance of the image signal, and normalizes the luminance. If the luminance of the image signal is too low or too high, a correction signal is output to the light source control unit 55, which increases or decreases the amount of light emitted by each light source 51, 53 so that the image signal reaches the desired luminance level.

[0032] Next, color matching unit 65b adjusts the normalized image data so that the color tone of the image becomes the desired color tone. For example, if the image signal is composed of R, G, and B color signals, the intensity balance of the R, G, and B color signals is adjusted. In light source device 41, light source control unit 55 controls the light emission amounts of blue laser light source 51 and violet laser light source 53, respectively, so that the light intensity ratio between the light emitted by blue laser light source 51 and the light emitted by violet laser light source 53 can be arbitrarily changed. Therefore, the color tone and total illuminance of the illumination light may change depending on the set light intensity ratio. Therefore, brightness calculation unit 65a and color matching unit 65b correct the image signal depending on the set light intensity ratio to maintain the color tone and brightness of the observed image at a predetermined constant level.

[0033] Then, the image calculation unit 65c performs a predetermined or requested image calculation, and the display image generation unit 65d generates output image information based on the result and outputs it to the control unit 67.

[0034] Next, an example in which the above-described endoscope device 100 is used to observe blood vessel images on the surface of living tissue will be described. Figure 5 is a schematic diagram illustrating blood vessels in the mucosal surface layer of biological tissue. The mucosal surface layer of biological tissue is formed from blood vessels B1 in the deep mucosal layer to capillaries B2, such as a resinous vascular network, and it has been reported that lesions in biological tissue appear in the fine structures of capillaries B2 and other blood vessels. Therefore, in recent years, attempts have been made to use endoscopic devices to enhance the images of capillaries in the mucosal surface layer using light with a specific narrowband wavelength, thereby enabling early detection of minute lesions and diagnosis of the extent of lesions.

[0035] When illumination light is incident on biological tissue, the incident light propagates diffusely within the tissue. However, the absorption and scattering characteristics of biological tissue are wavelength-dependent, with shorter wavelengths tending to exhibit stronger scattering. In other words, the penetration depth of light varies depending on the wavelength of the illumination light. Meanwhile, blood flowing through blood vessels has a maximum absorption wavelength near 400 to 420 nm, providing high contrast. For example, illumination light in the wavelength range λa near 400 nm can provide vascular information from capillaries in the mucosal surface, while illumination light in the wavelength range λb near 500 nm can provide vascular information including that of deeper blood vessels. Therefore, for observing blood vessels in the surface layer of biological tissue, a light source with a central wavelength of 360 to 800 nm, preferably 365 to 515 nm, and more preferably 400 to 470 nm, is used.

[0036] Therefore, as shown in Fig. 6, an example of an observation image obtained by an endoscope device, an observation image obtained using white light as illumination light provides an image of blood vessels in a relatively deep layer of the mucosa, but the fine capillaries in the surface layer of the mucosa appear blurred. On the other hand, an observation image obtained using narrow-band illumination light with only short wavelengths provides a clear view of the fine capillaries in the surface layer of the mucosa.

[0037] In this configuration example, the light source control unit 55 (see FIG. 2) of the endoscope device 100 can freely change the light intensity ratio between the light emitted by the blue laser light source 51 with a center wavelength of 445 nm and the violet laser light source 53 with a center wavelength of 405 nm. The light intensity ratio can be changed, for example, by operating a switch 89 provided on the operation unit 23 of the endoscope 11 shown in FIG. 1, and the image can be enhanced to make it easier to observe the capillaries in the surface layer of the mucosa. In other words, when the blue laser light component from the blue laser light source 51 is abundant, the illumination light has a large white light component due to this blue laser light and the excited emission light from the phosphor 57, and an observation image such as the white light observation image in FIG. 6 can be obtained. However, because the blue laser light, which is narrow-band light, is mixed in the illumination light, the capillaries in the surface layer are enhanced in the observation image.

[0038] Furthermore, when there is a large amount of violet laser light component from violet laser light source 53, an observation image like the narrowband light observation image in Fig. 6 can be obtained. Then, by increasing or decreasing the ratio of the light intensity of the light emitted from blue laser light source 51 and violet laser light source 53, that is, by increasing or decreasing the proportion of the violet laser light component to the total illumination light component, it is possible to perform observation in which the fine capillaries in the mucosal surface layer are continuously highlighted.

[0039] Therefore, the more the violet laser light component is present, the clearer the fine capillaries contained in the thin depth region of the mucosal surface will be displayed in the observation image, and the fewer the violet laser light component is present, the more vascular information contained in a wide depth region extending from the mucosal surface to the deeper layers will be displayed. This allows a pseudo-display of the vascular distribution in the depth direction from the mucosal surface, and vascular information in the depth direction of the observation site can be extracted as continuous information corresponding to each depth range. In particular, in this configuration example, vascular information obtained with the blue laser light and vascular information in the more superficial layers obtained with the violet laser light are both extracted, and these pieces of information can be compared by displaying them as images, allowing vascular information, including more superficial blood vessels, that could not be observed with blue laser light, to be observed with improved visibility.

[0040] Furthermore, in the tip 35 (see FIG. 1) of the electronic endoscope where the image sensor 21 is located, the amount of heat generated is increasing along with the increase in power consumption due to the recent trend toward higher pixel counts and faster frame rates, which places a limit on the light that can be emitted from the tip 35. Under these circumstances, by changing the light intensity ratio of each light source, it is possible to increase the required amount of light emitted while suppressing the total amount of illumination light, thereby solving problems such as relying solely on image processing and only obtaining images with a lot of noise.

[0041] 7a, 7b, and 7c show enlarged images of the inside of the lip observed with the endoscope device 100 under the same light intensity and similar image processing conditions. The figures show an observation image (Fig. 7a) using white illumination light consisting of blue laser light with a central wavelength of 445 nm and excitation emission light from a phosphor. Also shown are an observation image (Fig. 7b) obtained when the light intensity ratio between violet laser light with a central wavelength of 405 nm and blue laser light with a central wavelength of 445 nm was 50:50, and an observation image (Fig. 7c) obtained when the light intensity ratio between violet laser light with a central wavelength of 405 nm and blue laser light with a central wavelength of 445 nm was 75:25. Note that both Figs. 7b and 7c also include excitation emission light from a phosphor excited by blue laser light with a central wavelength of 445 nm.

[0042] In the observation images shown in Figure 7, the observation depth from the surface decreases in the order a → b → c depending on the wavelength of the illumination light, and the amount of minute capillaries that are visible increases. In other words, the more the proportion of violet laser light in the illumination light is increased, the more the capillaries in the surface layer are emphasized, allowing for higher contrast and clearer observation of the capillaries in the mucosal surface and the fine mucosal patterns. Furthermore, because the light intensity ratio between the blue and violet laser lights can be freely changed in a stepless manner, it is easy to infer the three-dimensional vascular structure in the mucosal surface from the changes in the observation image when the light intensity ratio is continuously changed, or to selectively and clearly display the desired observation target.

[0043] For violet and blue light, which have wavelength bands close to each other, it is difficult to increase or decrease the amount of light in the violet region separately from the light in the blue region using conventional wavelength-limiting means such as a halogen lamp or xenon lamp and a color filter. If a wavelength-limiting means is used in the optical path to narrow the emission spectrum, not only is the amount of light from the original halogen lamp or xenon lamp low, but the amount of light in the violet region becomes even more insufficient. Furthermore, if an attempt is made to widen the half-width of the emission spectrum to increase the amount of light in the violet region, the narrowing of the illumination light band cannot be achieved, resulting in insufficient image enhancement of the desired blood vessels.

[0044] When the amount of illumination light is insufficient, this can generally be addressed by increasing the sensitivity of the image sensor or by lowering the frame rate. However, increasing the sensitivity of the image sensor during image capture has the disadvantage of increasing the noise component of the captured image. Furthermore, lowering the frame rate and increasing the sensitivity increases blurring, making the observed image more difficult to see. In this configuration example, laser light is used as the light source, so high-intensity illumination light can be obtained consistently and stably, resulting in brighter observed images with low noise and good image quality. Furthermore, sufficient illumination is obtained even when capturing distant scenes.

[0045] The light intensity ratio is changed by the light source control unit 55 shown in FIG. 2 controlling the light sources 51 and 53. Next, a method for the surgeon to change this light intensity ratio while viewing the observation image will be explained with reference to FIGS. 8 and 9. 8 shows an example of a display screen 71 of the display unit 15 that displays an observation image obtained by the endoscopic device 100. The display screen 71 is provided with an endoscopic image area 73 that displays an observation image obtained by the endoscopic device, a normal image switch button 75 that displays an observation image obtained by normal white light illumination in the endoscopic image area 73, and a narrowband light image switch button 77 that displays an observation image obtained by narrowband illumination light of violet laser light, as well as an adjustment bar 79 and knob 81 for adjusting the light intensity ratio. Then, based on instructions from the input unit 17 such as a mouse or keyboard, the knob 81 is slid within the adjustment bar 79 to adjust the light intensity ratio so as to obtain a desired observation image.

[0046] The control unit 67 determines the light intensity ratio according to the position of the knob 81 of the adjustment bar 79, and drives each of the light sources 51, 53 so that the light intensity of each of the light sources 51, 53 corresponds to this light intensity ratio. Here, the relationship between the light intensity ratio and the light intensity of each of the light sources 51, 53 is stored in the storage unit 83 (see FIG. 2) as a light intensity ratio correspondence table, and the control unit 67 determines the light intensity of each of the light sources 51, 53 by referring to the light intensity ratio correspondence table in the storage unit 83.

[0047] As described above, when increasing or decreasing the light intensity of each of the light sources 51, 53 (see FIG. 1) to set the desired light intensity ratio, the control unit 67 determines the light intensity of each of the light sources 51, 53 by referring to a pre-stored light intensity ratio correspondence table based on the light intensity ratio set on the display screen 71. This allows the endoscope operator to set the light intensity of each of the light sources 51, 53 to the desired light intensity ratio with a simple operation, without having to directly set it.

[0048] 9, the light intensity ratio may be changed by using a setting unit 85 for adjusting the intensity balance, brightness, and contrast of the R, G, and B color components of the image signal, or may be used in combination with the adjustment of the light intensity ratio changing knob 81. This allows the image to be displayed with any desired image enhancement, such as by expressing the desired observation subject in pseudocolor, and increases the flexibility in changing the displayed image, making it easier to diagnose.

[0049] Next, a method for driving the light sources 51 and 53 by the light source control unit 55 will be described. The light source control unit 55 shown in Fig. 2 controls the amount of light emitted from each of the light sources 51 and 53 based on instructions from the input unit 17. Each of the light sources 51 and 53 has a relationship R1 between the applied current and the amount of light emitted, as shown in Fig. 10, and a desired amount of light emitted is obtained by controlling the current applied to each of the light sources 51 and 53. For example, to obtain the amount of light emitted La, the applied current is set to Ib, and the amount of light emitted Lb based on the relationship R1 is ensured. Furthermore, the difference ΔL between the amounts of light emitted Lb and La is obtained as a fine adjustment by superimposing a pulse-modulated pulse current on the applied current.

[0050] For example, the light emission amount La can be obtained by a pulse current with the applied current Ib as a bias, as shown in Figure 11. Such bias current control and pulse modulation control ensure a wide dynamic range of the light emission amount that can be set.

[0051] In this case, various drive waveforms can be used for pulse modulation control. For example, using a pulse waveform, as shown in FIG. 12(a), that repeatedly switches on and off in synchronization with the light accumulation time of one image frame of the image sensor reduces the influence of dark current in the CCD or CMOS image sensor, improving image sharpness. Furthermore, using a pulse waveform with a sufficiently fast period relative to the light accumulation time, as shown in FIG. 12(b), can reduce the occurrence of flicker related to image display and also reduce image noise due to laser speckle. Furthermore, using a mixed pulse waveform, as shown in FIG. 12(c), in which the on period of the pulse waveform of FIG. 12(a) is replaced with the fast-period pulse waveform of FIG. 12(b), can achieve the above-mentioned effects in addition to flicker reduction.

[0052] 13, by alternately lighting up the light sources 51 and 53 and controlling them so that the light emission amount alternately reaches its maximum, the maximum driving power of the light source device 41, which is the combination of the light sources 51 and 53, can be reduced, and the burden on the living body as the subject can also be reduced. Also, it is possible to individually acquire images captured by the illumination light of each light source 51 and 53, in which case inter-image calculations of the acquired images become possible, improving the flexibility of image processing.

[0053] FIG. 14 shows a schematic relationship between the absorption wavelength band of hemoglobin and the emission wavelength of each of the light sources 51 and 53. As mentioned above, hemoglobin contained in blood has a maximum absorption at wavelengths around 400 to 420 nm, and light emitted from each of the light sources 51, 53 with an emission wavelength that is within or close to the hemoglobin absorption wavelength band can capture blood vessel information with high contrast. Furthermore, by setting the emission wavelengths of the light sources 51, 53 to have similar absorption rates on either side of the hemoglobin absorption wavelength band, the intensity of blood vessel information is not affected by the light intensity ratio of the light sources 51, 53. In other words, even if the light intensity ratio of the light sources 51, 53 is changed, the detection sensitivity of the blood vessel image itself remains constant.

[0054] By avoiding the maximum peak wavelength of the hemoglobin absorption wavelength band and using light in a wavelength range that has an appropriate absorption rate in the base region of the absorption wavelength band as illumination light, it is possible to prevent the observed image from becoming dark due to the influence of absorption by blood that has seeped into the surface layer of the tissue when bleeding occurs from biological tissue in the observation area.

[0055] The observation images obtained by illumination with the narrowband violet laser light described above and illumination with white light can be switched instantaneously for each frame. Figure 15 shows a schematic diagram of the image displayed on the display unit 15 (see Figures 1 and 2) when the endoscope operator moves the insertion portion of the endoscope inside the subject, performs observation with narrowband light at the desired observation position, and then moves it to the next observation position.

[0056] Switching from a normal display image using white light observation to a display image using narrowband light observation, and vice versa, is possible even in units of one frame of the image captured by the image sensor 21 (a full-color image using three colors: R, G, and B). This allows images to be displayed in real time without color shift, even when observing while moving the endoscope insertion portion, eliminating any discomfort for the surgeon. This means that a good observation image that reliably tracks even rapid movements of the endoscope can be provided, improving the operability of the endoscope device.

[0057] Furthermore, the display pattern of the observation image on the display unit 15 can be freely arranged between a normal image during white light observation and a narrow-band light image during narrow-band light observation. For example, as shown in Fig. 16, the normal image and the narrow-band light image are arranged in separate regions on the same screen and displayed simultaneously, making it easy to compare the normal image with the narrow-band light image in which specific information is emphasized. In this case, the blue laser light source 51 is turned on to capture the normal image using white light, and in the next frame, the blue laser light source 51 and the violet laser light source 53 are turned on simultaneously to capture the narrow-band light image. This process is repeated, and the resulting normal image and narrow-band light image are displayed in their respective display regions.

[0058] 17 shows a display screen of the so-called P in P (Picture in Picture) function, which simultaneously displays a narrowband light image of a desired range superimposed on a normal image. The display range of the narrowband light image can be set to any position and any size within the normal image by instructions from the input unit 17 (see FIGS. 1 and 2). Within the display range of the narrowband light image, an image of the subject at the same position as the display position in the normal image is displayed. This makes comparative observation at the same position even easier. Note that the above display pattern is merely an example, and it goes without saying that a display form in which the normal image is embedded in the narrowband light image may also be used, or any other combination of displays may be used.

[0059] Next, the setting of the light intensity ratio between the blue laser light and the violet laser light will be described. In the above description, it has been stated that the light intensity ratio of the light emitted from blue laser light source 51 and violet laser light source 53 shown in Fig. 2 can be arbitrarily set by light source control unit 55 in response to an instruction from input unit 17. Here, a case will be described in which a plurality of light intensity ratios are registered in advance, and one of the light intensity ratios is designated from input unit 17.

[0060] For example, in endoscopic observation of blood vessel images, different endoscope operators may have different preferences for the light intensity ratio of blue laser light to violet laser light. For example, operator A may prefer an observation image with a light intensity ratio of violet laser light λa to blue laser light λb of 60:40, while operator B may prefer a light intensity ratio of 75:25. In this case, as shown in FIG. 18 , light intensity ratio information associating the operator's name, which serves as key information, with the operator's preferred light intensity ratio is pre-registered in the storage unit 83 (see FIG. 2 ) or the like as a light intensity ratio table. Then, when information corresponding to the operator's name is input from the input unit 17, the control unit 67 automatically sets the desired light intensity ratio by referring to the light intensity ratio table in the storage unit 83. This allows the light intensity ratio to be set according to the operator's preference.

[0061] Furthermore, since the optical characteristics may differ depending on the individual endoscope, individual identification information that identifies the individual endoscope may be used as key information instead of the surgeon's name, which is the key information described above. In this case, the number, model name, etc. assigned to each individual endoscope is used, and information on the corresponding light intensity ratio is registered in advance as a light intensity ratio table. This makes it possible to set the optimal light intensity ratio according to the type and characteristics of each individual endoscope.

[0062] Furthermore, a configuration may be adopted in which multiple light intensity ratios are preset, allowing the surgeon to freely select one by simple operation. For example, as shown in an example of display on the display unit 15 in FIG. 19, multiple preset light intensity ratios are displayed as "selection buttons" 87 on a GUI (Graphical User Interface), allowing the surgeon or assistant to freely select one by looking at the display unit 15 (see FIGS. 1 and 2) and operating the input unit 17. Furthermore, if the display unit 15 is a touch panel, the surgeon can directly touch the selection button 87 on the display unit 15 while gazing at the display unit 15 during observation, allowing for more intuitive and quick switch operation. Furthermore, the surgeon can compare each observation image that changes as the light intensity ratio is changed without taking his or her eyes off the image, allowing for more reliable recognition of subtle image changes.

[0063] Furthermore, the light intensity ratio can be changed not only from the display pattern on the display unit 15, but also by operating a switch 89 provided on the operation unit 23 of the endoscope 11 shown in Fig. 1 as a changeover switch. By providing the switch 89 on the operation unit 23, the surgeon can quickly and easily change the light intensity ratio without removing his or her hands from the endoscope 11, improving the operability of the endoscope.

[0064] Various types of switches such as a toggle switch, push switch, slide switch, rotary switch, etc. can be used as this switch 89, and different preset light intensity ratios are set sequentially with each press or depending on the contact position of a multi-contact switch, as shown in Fig. 20. For example, it is possible to sequentially select observation light modes with multiple light intensity ratios, such as normal light observation using white light from blue laser light source 51 and phosphor 57 in Fig. 2, narrow-band light observation A, B, C, etc. in which narrow-band light from violet laser light source 53 is superimposed on white light at a predetermined ratio, or narrow-band light observation using only narrow-band light.

[0065] If the switch operation is a repeated pressing operation or the like, there is no need to visually check the switch 89, and the switch can be operated while watching the display unit 15. This allows for easy switching to illumination light suitable for diagnosis. Note that the switch 89 for switching the light intensity ratio is not limited to switching between preset light intensity ratios, and may be a volume switch or slide switch that continuously changes the light intensity ratio. In this case, it becomes easy to optimally adjust the light intensity ratio depending on the observation target. Furthermore, by continuously changing the light intensity ratio through switch operation, continuous changes in the observation image can be observed, allowing for a more accurate understanding of the vascular structure.

[0066] Next, correction of color changes in the observed image that occur as the light intensity ratio is changed will be described. Image signals R, G, and B are input to the image processing unit 65 shown in Fig. 4, and these image signals R, G, and B are normalized in luminance by a luminance calculation unit 65a and converted into image data of Rnorm, Gnorm, and Bnorm. The normalized image data Rnorm, Gnorm, and Bnorm are corrected to a color tone according to the light intensity ratio by a color matching unit 65b. That is, the color matching unit 65b calculates the image data Radj, Gadj, and Badj after color tone correction by calculation as shown in equation (1).

[0067]

number

[0068] where k R , k G , k B are color conversion coefficients for each color, and are determined according to the light intensity ratio set at the time of image capture. Figure 21 shows a color conversion coefficient table that determines the color conversion coefficients for each color corresponding to the light intensity ratio. The color conversion coefficient k R , k G , k B are set as R00 to R100, G00 to G100, and B00 to B100 corresponding to each light intensity ratio, and are stored in the storage unit 83 (see FIG. 2). By substituting the color conversion coefficients corresponding to the light intensity ratios used during image capture into equation (1), color-corrected image data Radj, Gadj, and Badj are obtained.

[0069] The color conversion coefficients may be expressed as a mathematical formula instead of the table shown in Fig. 21, or only the representative points may be digitized and the other points may be calculated by interpolation. In this case, the amount of information stored in the storage unit 83 can be reduced.

[0070] According to the endoscope device 100 described above, by using violet laser light (and blue laser light), i.e., illumination light in a short wavelength band particularly suited to observing blood vessels, it is possible to observe microvessels on the surface of biological tissue with enhanced image enhancement, facilitating observation of the microstructure of blood vessels. Furthermore, by continuously changing the light intensity ratio of the emitted violet laser light and blue laser light (white light), it is possible to easily observe the blood vessel structure that changes in the depth direction from the surface of biological tissue, and the blood vessel structure in the more superficial layers of biological tissue can be clearly grasped. Therefore, when observing biological tissue with white light or special light, desired tissue information of the biological tissue can be obtained in a clearer state suited to diagnosis, enabling smooth endoscopic diagnosis.

[0071] Furthermore, if the endoscope device 100 is configured as a so-called magnifying endoscope equipped with an imaging optical system that can magnify and observe the observation area, the separation between the microvessels in the surface layer of biological tissue and the mucosal micropattern can be improved, enabling more advanced endoscopic diagnosis. In other words, magnified observation can confirm the presence of abnormalities such as variations in microvessel diameter, uneven shape, dilation, and tortuosity, as well as the disappearance or irregular miniaturization of the mucosal micropattern, providing useful information for diagnosing the type of adenocarcinoma, for example.

[0072] Next, another example of the configuration of the endoscope apparatus will be described. First, an endoscope apparatus that utilizes the difference in absorption characteristics between hemoglobin and oxyhemoglobin to determine the oxygen concentration distribution of blood within an observation image will be described. The absorption spectra of hemoglobin Hb with low oxygen concentration and oxygen-saturated oxyhemoglobin HbO2 at wavelengths from 450 nm to 700 nm are shown in Figure 22. As illumination light for observation, wavelength λ1, the isosbestic point where the absorption of hemoglobin Hb and oxyhemoglobin HbO2 is equal, and wavelength λ2, where the absorption of the two is different, are selected, and the luminance Ab1 of the observed image obtained by illumination light of wavelength λ1 and the luminance Ab2 of the observed image obtained by illumination light of wavelength λ2 are determined.

[0073] The ratio of the brightnesses Ab1 and Ab2 of these images is an index of the oxygen concentration in the blood, and can be used to monitor changes in the metabolic state of living tissue. It is generally said that cancerous areas have low oxygen concentrations, and oxygen concentration is useful information for endoscopic diagnosis.

[0074] 23 shows an example of the configuration of the light source device 41 and endoscope 11 in an endoscope device 200 for determining the oxygen concentration distribution. In this example, blue-green laser light from a blue-green laser light source 91 with a center wavelength of 515 nm is used as the isosbestic illumination light, and red laser light from a red laser light source 93 with a center wavelength of 630 nm is used as the illumination light with a different absorption wavelength. Of course, if the primary focus is on measuring the oxygen concentration distribution, the violet laser light source 53 can be omitted. Note that the same reference numerals in the figure denote the same members as in FIG. 2, and their explanations will be omitted.

[0075] It is preferable that the optical fibers 45A, 45B, 45C, and 45D having the above-described configuration are each selected and used optimally according to the wavelength to be used. - The transmission loss is wavelength dependent and changes depending on the concentration, and the absorption rate at specific wavelengths in the infrared range is different from that at wavelengths in the visible range. Therefore, when the wavelength of the light source is 650 nm or less, an optical fiber with a core with a high hydroxyl group concentration is used, and when the wavelength is over 650 nm, an optical fiber with a core with a low hydroxyl group concentration is used.

[0076] To obtain the oxygen concentration distribution, first, an image of the observation area is captured using blue-green laser light from a blue-green laser light source 91 as illumination light, and then an image of the observation area is captured using red laser light from a red laser light source 93 as illumination light. During imaging, the light output from each light source 91, 93 is adjusted so that the average luminance value of the observation image data is constant. Then, from the luminances Ab1, Ab2 of the obtained observation images, the oxygen concentration index Oindx is obtained for each pixel using equation (2). Oindx = k (Ab2 / Ab1) (2) where k is a coefficient.

[0077] This allows a distribution image of the oxygen concentration index Oindx to be obtained, and the distribution state of the oxygen concentration within the observed image can be grasped.

[0078] Similarly to the blue laser light source 51 and the violet laser light source 53, the light source control unit 55 can individually change the intensity of the emitted light from the blue-green laser light source 91 and the red laser light source 93, and the light intensity ratio of the emitted light is adjusted depending on the object of observation, the procedure, etc. Each laser light source 91, 93 may be caused to emit light within one frame of an imaging signal, and the light intensity ratio may be adjusted as appropriate. The blue-green laser light is suitable for observing microvessels and redness in biological tissue, and the red laser light is suitable for observing deep blood vessels in biological tissue. Therefore, by changing the light intensity ratio of the emitted light from these laser lights, information from different regions in the depth direction or information from different objects can be displayed in an emphasized manner, as described above.

[0079] Furthermore, even if each light source emits light simultaneously within one frame of the imaging signal, the light component from the blue-green laser light source 91, the light component from the red laser light source 93, or the amount of excitation light can be detected separately from each of the R, G, and B image signals output from the imaging element 21.

[0080] In this way, the ratio of the intensity of blue-green laser light to white light, the ratio of the intensity of red laser light to white light, or the ratio of the intensity of blue-green laser light and red laser light can be arbitrarily and continuously changed, thereby improving the visibility of the desired observation target. Furthermore, by increasing the number of illumination light types and making the endoscope more multifunctional, even if an unexpected observation becomes necessary during endoscopic diagnosis, observation can be performed quickly with the appropriate illumination light for the observation target without removing the endoscope from the subject. Note that instead of generating white light using blue laser light and excitation light from a phosphor, a white light source such as a halogen lamp can be used. In this case, the intensity of the blue laser light and the intensity of the white light can be controlled separately, allowing for more precise adjustment of the light intensity ratio.

[0081] Next, an endoscope device in which the optical path from the light source device 41 to the endoscope 11 is configured by a single optical fiber 45 will be described. 24 shows an example of the configuration of the light source device 41 and the endoscope 11. In the endoscope device 300, blue laser light from a blue laser light source 51 with a central wavelength of 445 nm is converged with violet laser light from a violet laser light source 53 with a central wavelength of 405 nm on the optical path before being introduced into an optical fiber 45A via a condenser lens (not shown). Optical Coupling Means The dichroic prism 95 is provided as a

[0082] Phosphor 97 arranged on the light emission side of optical fiber 45A has the property of absorbing a portion of the blue laser light from blue laser light source 51 and emitting excitation light in green to yellow, forming white light together with the blue laser light that is not absorbed and transmitted, and transmitting the violet laser light from violet laser light source 53 with almost no absorption. For this reason, phosphor 97 is selected from a material that is excited and emitting light with high efficiency by the blue laser light and forms white light together with the blue laser light, and a material that reduces the amount of light emitted by the phosphor when exposed to violet laser light.

[0083] In principle, wavelength conversion by the phosphor 97 involves wavelength conversion losses (Stokes losses) such as heat generation. Therefore, it is known that selecting an excitation wavelength with a long emission wavelength increases the luminous efficiency of the phosphor and is advantageous in suppressing heat generation of the phosphor. Therefore, in this configuration example, white light is generated using laser light on the long wavelength side, thereby increasing the luminous efficiency.

[0084] Fig. 25 shows an example of the emission spectrum of illumination light from light source device 41 and phosphor 97 shown in Fig. 24. As shown in Fig. 25, it is desirable that the amount of light emitted by phosphor 97 excited by violet laser light is several times smaller (at least 1 / 3, preferably 1 / 5, and more preferably 1 / 10 or less) than the amount of light emitted by blue laser light.

[0085] As described above, according to this configuration, the optical paths of the blue laser light and the violet laser light are integrated by the dichroic prism 95, so that the light is guided from the light source device 41 to the phosphor 97 by a single optical fiber 45A, and moreover, the illumination light emission port can be contained in a single location on the phosphor 97, thereby improving space efficiency and contributing to a thinner diameter for the endoscope insertion portion.

[0086] Furthermore, even when other laser light sources are provided in addition to blue laser light source 51 and violet laser light source 53, the optical paths may be similarly integrated via optical coupling means such as a dichroic prism. Furthermore, for phosphor 97, a fluorescent material that is not or is difficult to excite with the wavelengths of the other laser light sources may be used.

[0087] Here, specific examples of the material for the phosphor 97 in this configuration example include a crystalline solid-state fluorescent material containing lead (Pb) as an additive element and based on calcium gallium tetrasulfide (CaGa2S4), as described in JP 2006-2115 A, or a crystalline solid-state fluorescent material containing lead (Pb) and cerium (Ce) as additive elements and based on calcium gallium tetrasulfide (CaGa2S4). This phosphor material can emit fluorescence across almost the entire visible range, from about 460 nm to about 660 nm, and improves color rendering properties when illuminated with white light.

[0088] In addition, it is possible to use a combination of green phosphor LiTbW2O8 (see Odaki Tsutomu, "On Phosphors for White LEDs," IEICE Technical Research Report ED2005-28, CFM2005-20, SDM2005-28, pp. 69-74 (2005-05) etc.), beta-sialon (β-sialon:Eu) blue phosphor (see Hirosaki Naoto, Kai Eijun, Sakuma Ken, "Development of Sialon-Based New Phosphors and White LEDs Using Them," Journal of the Japan Society of Applied Physics, Vol. 74, No. 11, pp. 1449-1452 (2005), or Yamamoto Akira, Department of Pionics, Tokyo University of Technology, Journal of the Japan Society of Applied Physics, Vol. 76, No. 3, p. 241 (2007)), CaAlSiN3 red phosphor, etc. Beta-sialon is a silicon nitride crystal with aluminum and acid dissolved in it. 6-z Al2O2N 8-z (z is the amount of solid solution) The phosphor 97 may be a mixture of LiTbW2O8, beta-sialon, or CaAlSiN3, or may be a layered configuration of these phosphors.

[0089] Each of the phosphors exemplified above is excited by blue laser light from blue laser light source 51, but is not excited to emit light by purple laser light from other purple laser light source 53, that is, the main excitation wavelength band specific to the phosphor does not include the emission wavelengths of other light sources.

[0090] In the endoscope device described above, white light is generated by blue laser light and excited emission light from phosphors 57 and 97. However, this is not limiting, and various combinations of light sources and phosphors are possible for generating white light, such as a configuration using a phosphor that generates green excited emission light when stimulated by blue laser light and a phosphor that generates red excited emission light when stimulated by violet laser light.

[0091] As such, the present invention is not limited to the above-described embodiments, and modifications and applications by those skilled in the art based on the description in the specification and well-known techniques are also contemplated by the present invention and are included in the scope of protection sought.

[0092] As described above, the present specification discloses the following: (1) An illumination device for an endoscope that obtains illumination light using light emitted from a plurality of light sources, a first light source using a semiconductor light emitting element as a light source; a second light source using a semiconductor light emitting element having an emission wavelength different from that of the first light source; a wavelength conversion member that is excited and emits light by light emitted from at least one of the first and second light sources; a light intensity ratio changing means for changing a light intensity ratio between the light emitted from the first light source and the light emitted from the second light source; An illumination device for an endoscope comprising: This endoscopic illumination device allows the ratio of the light intensity of the light emitted from the first light source to the light emitted from the second light source to be freely changed, so that illumination light having a large component of light emitted from the first light source, illumination light having a large component of light emitted from the second light source, or illumination light somewhere in between can be generated as desired. This makes it possible to provide illumination light suitable for diagnosis according to the absorption and scattering characteristics of biological tissue, and to obtain desired tissue information of biological tissue more clearly.

[0093] (2) The illumination device for an endoscope according to (1), An illumination device for endoscopes, wherein the emission wavelength of a semiconductor light emitting element of at least one of the first light source and the second light source is within the range of 400 nm to 470 nm. This illumination device for endoscopes uses light from a semiconductor light-emitting element with a wavelength of 400 nm to 470 nm, making it possible to observe blood vessels, particularly in the surface layer of living tissue, in an emphasized manner.

[0094] (3) An illumination device for an endoscope according to (1) or (2), an illumination device for endoscopes, wherein the wavelength conversion member is a phosphor that generates white light by combining emission light emitted by the wavelength conversion member in response to excitation light and light emitted from at least one of the first and second light sources; This endoscopic illumination device generates white light by emitting light from a wavelength conversion member using light from a semiconductor light-emitting element as excitation light, thereby providing high-intensity white light with high luminous efficiency. Furthermore, because the semiconductor light-emitting element is used as the excitation light source, the intensity of the white light can be easily adjusted, and there is little change in the color temperature and chromaticity of the white light.

[0095] (4) An illumination device for an endoscope according to any one of (1) to (3), The illumination device for endoscopes further comprises at least one third light source having a semiconductor light emitting element with an emission wavelength different from that of the first and second light sources, the third light source having a different emission wavelength for each light source. This endoscopic illumination device further includes a third light source with a different emission wavelength, which broadens the wavelength band of the illumination light and increases the degree of freedom in selecting the wavelength of the illumination light. This allows for the generation of illumination light for forming various images, such as a blood vessel-enhanced image using purple and blue light, or an oxygen concentration distribution image using green and red light.

[0096] (5) An illumination device for an endoscope according to any one of (1) to (4), an illumination device for endoscopes, comprising optical coupling means that is disposed midway along the optical path from the first light source to the wavelength conversion member, and that combines light emitted from at least the second light source with light emitted from the first light source and guides the combined light to the wavelength conversion member. According to this endoscopic illumination device, only a single optical path is required from the optical coupling means to the wavelength conversion member, and when the endoscopic illumination device is incorporated into an endoscope apparatus, a simpler configuration with improved space efficiency can be achieved.

[0097] (6) An illumination device for an endoscope according to any one of (2) to (5), an illumination device for endoscopes, wherein one of the emission wavelengths of the first light source and the second light source is set to the shorter wavelength side of the maximum peak wavelength in the absorption wavelength band of hemoglobin, and the other is set to the longer wavelength side. This endoscopic illumination device allows for the capture of vascular information with high contrast. In addition, by reducing the illumination light component near the maximum absorption wavelength of hemoglobin, it is possible to prevent the observed image from becoming dark due to absorption by blood that has seeped into the tissue surface layer.

[0098] (7) An illumination device for an endoscope according to any one of (1) to (6), The light intensity ratio changing means changes the light intensity of each of the light sources independently. According to this illumination device for endoscopes, the amount of emitted light can be freely changed for each light source, thereby increasing the degree of freedom in adjusting the spectral characteristics of the illumination light that is ultimately formed by the light from each light source.

[0099] (8) An illumination device for an endoscope according to any one of (1) to (7), further comprising an input means for inputting light quantity ratio information that specifies a desired light quantity ratio; The light intensity ratio changing means determines the light intensity of each of the light sources that achieves the desired light intensity ratio based on the light intensity ratio information input to the input means. With this endoscope illumination device, the light intensity ratio is specified based on the light intensity ratio information input from the input means, and the light intensity of the light source is determined to achieve this light intensity ratio. In other words, the light intensity ratio can be freely changed as specified.

[0100] (9) The illumination device for an endoscope according to (8), further comprising a storage means for storing a light quantity ratio table in which a plurality of light quantity ratios are associated with key information; the light amount ratio information includes the key information, an illumination device for an endoscope, wherein the light intensity ratio changing means determines the desired light intensity ratio by referring to the light intensity ratio table based on key information included in the light intensity ratio information input from the input means; According to this endoscopic illumination device, a desired light intensity ratio is determined by referring to the light intensity ratio table based on key information included in the light intensity ratio information. In other words, by registering a light intensity ratio for each key information in the light intensity ratio table in advance, the light intensity ratio corresponding to the key information can be automatically determined simply by specifying the key information.

[0101] (10) The illumination device for an endoscope according to (9), An illumination device for an endoscope, wherein the key information is identification information of an operator of the endoscope device. According to this illumination device for endoscopes, the light intensity ratio can be set arbitrarily for each endoscope operator according to their preference.

[0102] (11) The illumination device for an endoscope according to (9), An illumination device for an endoscope, wherein the key information is individual identification information of the endoscope device. According to this illumination device for endoscopes, the light intensity ratio can be set for each individual endoscope device according to the type and characteristics of each individual endoscope device.

[0103] (12) An illumination device for an endoscope according to any one of (9) to (11), an illumination device for endoscopes, wherein the input means is a changeover switch for designating one of a plurality of light intensity ratios set in the light intensity ratio table; According to this illumination device for endoscopes, a desired light intensity ratio can be arbitrarily selected from a plurality of light intensity ratios by operating a selector switch, and the light intensity ratio can be quickly and easily switched.

[0104] (13) An illumination means for emitting illumination light from any one of the illumination devices for endoscopes (1) to (12) from the distal end side of an insertion part of an endoscope that is inserted into a body cavity; an imaging means, which is mounted in the endoscope insertion section and has an imaging element for imaging the observation area illuminated with the illumination light, and outputs an image signal that becomes an observation image; An endoscope device comprising: According to this endoscope device, an observation area is irradiated with illumination light, in which the light intensity ratio of the light emitted from the first light source and the second light source is set to a desired light intensity ratio, and the observation area is imaged using an imaging element, thereby obtaining an observation image corresponding to the light intensity ratio. In other words, illumination light suitable for diagnosis can be irradiated, and desired tissue information of living tissue can be obtained more clearly.

[0105] (14) The endoscope device according to (13), An endoscope apparatus comprising a light source control means for causing at least the first light source and the second light source to emit light within one frame of an image signal from the imaging element. According to this endoscopic illumination device, by causing each light source to emit light within one frame of image signal and capturing an image using an imaging element, an observation image can be obtained in which the light emitted from multiple light sources is irradiated onto the observation area.

[0106] (15) The endoscope device according to (14), An endoscope apparatus in which the light source control means causes at least the first light source and the second light source to emit light at different timings within one frame of the image signal of the imaging element. According to this endoscope device, it is no longer necessary to simultaneously emit light from each light source, which reduces the burden on the subject and the power consumption of the device.

[0107] (16) An endoscope device according to any one of (13) to (15), an image processing means for generating an observation image for display based on the image signal output from the imaging device; a display means for displaying information including the display observation image; An endoscope device comprising: According to this endoscope device, by displaying information on the image signal from the imaging element on the display means, the observed image can be easily confirmed, and endoscopic diagnosis can be carried out more smoothly.

[0108] (17) The endoscope device according to (16), First image information captured by the display means under visible light including the emitted light from the first light source and the excited luminescence light from the wavelength conversion member; An endoscope apparatus that simultaneously displays, on the same screen, second image information captured under illumination light including the visible light and light emitted from the second light source. According to this endoscope device, the first image information, which is an observation image when visible light with a wide wavelength band is used as illumination light, and the second image information, which is an observation image when illumination light including narrow-band light, are simultaneously displayed on the same screen of the display means, which makes it easy to compare the normal observation image with the image in which specific information is emphasized.

[0109] (18) An endoscope device according to (16) or (17), First image information captured by the display means under visible light including the emitted light from the first light source and the excited luminescence light from the wavelength conversion member; an endoscope device that simultaneously displays either one of the image information captured under illumination light including the visible light and the light emitted from the second light source, superimposed on each other; According to this endoscope device, a normal observation image and an image in which specific information is emphasized are displayed in a superimposed manner, making it easy to perform comparative observation.

[0110] (19) The endoscope device according to any one of (13) to (18), a recording means for recording information including the observed image output from the image processing means, The recording means records the observed image and the light amount ratio in association with each other. With this endoscopic device, the observation image is recorded in association with the light intensity ratio that was set when the observation image was captured, so the range of use of the observation image can be expanded, such as by processing the recorded observation image according to the light intensity ratio at the time of capture. [Explanation of symbols]

[0111] 11 Endoscopy 13 Control device 15 Display section 17 Input section 19 Endoscope insertion part 21 Image sensor 23 Control section 35 Tip 37A,37B Irradiation port 41 Light source device 43 processors 45A, 45B, 45C, 45D Optical fiber 51 Blue laser light source (first light source) 53 Blue laser light source (second light source) 55 Light source control unit 57 Phosphor (wavelength conversion material) 59 Light deflection / diffusion member 65 Image processing section 67 Control Unit 71 Display screen 73 Endoscopic Imaging Area 75 Normal image switch button 77 Narrowband optical switch button 79 Adjustment bar 81 knob 83 Memory section 85 Adjustment section 87 Select button 89 Switch (changeover switch) 91 Blue-green laser light source 93 Red laser light source 95 Dichroic Prism 97 Phosphor (wavelength conversion material) 100,200,300 Endoscopic devices A,B profile B1,B2 blood vessels

Claims

1. An endoscope apparatus including an endoscope having an endoscope insertion section and an operation section, wherein illumination light using light emitted from a plurality of semiconductor light-emitting elements is emitted from a distal end side of the endoscope insertion section, and an observation image of an observation area is output, a violet semiconductor light-emitting element; a first semiconductor light emitting element that emits light with a wavelength longer than that of the violet semiconductor light emitting element; a second semiconductor light emitting element that emits light with a longer wavelength than the first semiconductor light emitting element; a light intensity ratio setting means for sequentially setting a light intensity ratio between the light emitted from the violet semiconductor light emitting element, the light emitted from the first semiconductor light emitting element, and the light emitted from the second semiconductor light emitting element to a plurality of different preset ratios each time a user operates the light intensity ratio; an imaging element mounted in the endoscope insertion section, which captures light reflected from the observation region irradiated with the illumination light and outputs an image signal of an observation image including blood vessel information; a light source control unit that controls the amount of light emitted from the purple semiconductor light emitting element, the amount of light emitted from the first semiconductor light emitting element, and the amount of light emitted from the second semiconductor light emitting element by pulse modulation control that controls drive waveforms of the purple semiconductor light emitting element, the first semiconductor light emitting element, and the second semiconductor light emitting element within one frame of the image signal of the image sensor based on the light amount ratio set by the light amount ratio setting unit, and that switches and lights up the purple semiconductor light emitting element, the first semiconductor light emitting element, and the second semiconductor light emitting element on a frame-by-frame basis; an image processing unit that performs image calculations using the image signal obtained in a frame in which the violet semiconductor light emitting element is lit, the image signal obtained in a frame in which the first semiconductor light emitting element is lit, and the image signal obtained in a frame in which the second semiconductor light emitting element is lit; An endoscope apparatus comprising:

2. The endoscope apparatus according to claim 1, The light intensity ratio setting unit is provided in the operation unit of the endoscope apparatus.

3. The endoscope apparatus according to claim 1 or 2, An endoscopic device, wherein the plurality of different ratios is three or more.

4. The endoscope apparatus according to any one of claims 1 to 3, An endoscope apparatus, wherein the plurality of different ratios are used to obtain the image signal that represents the object of observation in pseudo-color.

5. The endoscope apparatus according to any one of claims 1 to 4, An endoscope device, wherein the plurality of different ratios are determined according to individual identification information that identifies an individual endoscope device.

6. The endoscope apparatus according to any one of claims 1 to 5, An endoscope apparatus, wherein the plurality of different ratios include a ratio when the violet semiconductor light emitting element is not lit.

7. The endoscope apparatus according to any one of claims 1 to 6, an endoscope apparatus, wherein the illumination light emitted from the distal end side of the endoscope insertion portion includes emitted light that is excited and emitted by absorbing light emitted from the first semiconductor light emitting element;

8. An endoscopic device according to claim 7, the first semiconductor light emitting element is a blue semiconductor light emitting element, The second semiconductor light-emitting element is a red semiconductor light-emitting element.

9. The endoscope apparatus according to any one of claims 1 to 8, The endoscope is an endoscope device having an imaging optical system that can magnify and observe an area to be observed.

10. The endoscope apparatus according to any one of claims 1 to 9, the light source control unit increases or decreases the light emission amount of the violet semiconductor light-emitting element or the first semiconductor light-emitting element based on the luminance value of the image signal from the imaging element and the light intensity ratio set by the light intensity ratio setting means.

11. The endoscope apparatus according to any one of claims 1 to 6, the first semiconductor light emitting element is a blue-green semiconductor light emitting element, The second semiconductor light-emitting element is a red semiconductor light-emitting element.

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