Wavelength converter, light emitting device, medical system, electronic device and inspection method using the same

Abstract

The wavelength converter (1) of the present application comprises a first phosphor (2) and a second phosphor (3), wherein the first phosphor (2) is Cr 3+ Activated, the second phosphor (3) is Ce 3+ and Eu 2+ At least any one of the ions in the second phosphor (3) is activated. The fluorescence spectrum of the fluorescence emitted by the second phosphor (3) has a peak with a maximum fluorescence intensity in a wavelength range of 500 nm to less than 580 nm. The wavelength converter (1) emits fluorescence having a light component in the entire wavelength range of 500 nm to less than 580 nm. The wavelength converter (1) emits light of a spectrum in which the ratio of the minimum luminous intensity to the maximum luminous intensity is less than 40% in the wavelength range of 550 nm to 700 nm.

Description

Technical Field

[0001] The present invention relates to a wavelength converter and a light emitting device, a medical system, an electronic device and a testing method using the wavelength converter. Background Art

[0002] In recent years, a method for observing lesions called fluorescence imaging has attracted attention in the medical field. Fluorescence imaging is a method in which a fluorescent agent that selectively binds to lesions such as tumors is administered to a subject, and then the fluorescent agent is excited by specific light, and the fluorescence emitted by the fluorescent agent is detected and imaged by an image sensor to observe the lesions. According to fluorescence imaging, lesions that are difficult to observe visually can be observed.

[0003] As a representative fluorescence imaging method, it is known that there is a fluorescence imaging method (ICG fluorescence method) using indocyanine green (ICG) as a fluorescent agent. ICG is easily excited by near-infrared light (e.g., fluorescence peak wavelength is 770nm) that passes through the organism, and the emission wavelength is longer than the near-infrared light (e.g., fluorescence peak wavelength is 810nm). Therefore, by detecting the fluorescence emitted by ICG, the lesion inside the organism can be observed. The ICG fluorescence method can be said to be a low-invasive medical technology that can observe the lesion inside the organism without injuring the organism.

[0004] In order to utilize fluorescence imaging methods such as ICG fluorescence, a device that emits at least near-infrared light is required. As an optoelectronic element that emits near-infrared fluorescence, Patent Document 1 discloses an optoelectronic element including a semiconductor chip that emits a primary beam and a conversion material including Cr 3+ Ions and / or Ni 2+ ion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2018-518046

[0008] Patent Document 2: International Publication No. 2017 / 164214 Summary of the invention

[0009] As described above, in order to utilize a fluorescence imaging method such as the ICG fluorescence method, a device that emits at least near-infrared light is required. On the other hand, in order to visually observe the state of the mucosal surface layer by an image projected by a visible light image sensor or a lens, it is preferable to also emit visible light. Therefore, if there is a device that emits both visible light and near-infrared light, it is possible to take into account both normal observation using visible light and special observation using near-infrared light.

[0010] As a device that emits visible light and near-infrared light simultaneously, Patent Document 2 is known. Patent Document 2 discloses a light source device that combines a deep red phosphor that emits fluorescence including near-infrared fluorescence components, a phosphor that emits fluorescence having a wavelength different from that of the deep red phosphor, and a light emitting element.

[0011] However, in the fluorescence spectrum of the fluorescence emitted by such conventional devices, there is a problem that the visible light fluorescence component and the near-infrared fluorescence component are not sufficiently separated and the emission intensity of the deep red light that becomes noise of the near-infrared light image sensor becomes relatively high. Therefore, if normal observation and special observation are performed simultaneously using such conventional devices, there is a problem that the contrast of the obtained fluorescence imaging image becomes low.

[0012] The present invention is made in view of the problems of the prior art. Furthermore, the present invention aims to provide a wavelength converter that can fully separate the visible light fluorescence component and the near-infrared fluorescence component and emit a fluorescence spectrum with a relatively low luminous intensity of deep red light, and a light-emitting device, a medical system, an electronic device and a testing method using the wavelength converter.

[0013] In order to solve the above-mentioned problems, a wavelength converter according to a first aspect of the present invention includes a first phosphor and a second phosphor. The first phosphor is Cr. 3+ Activated, the second phosphor is Ce 3+ and Eu 2+ At least any one of the ions in the second phosphor is activated. The fluorescence spectrum of the fluorescence emitted by the second phosphor has a peak with a maximum fluorescence intensity in a wavelength range of 500 nm to less than 580 nm. The wavelength converter emits fluorescence having a light component in the entire wavelength range of 500 nm to less than 580 nm. The wavelength converter emits light of a spectrum in which the ratio of the minimum luminous intensity to the maximum luminous intensity is less than 40% in the wavelength range of 550 nm to 700 nm.

[0014] A light emitting device according to a second aspect of the present invention includes the wavelength converter according to the first aspect and a light source that emits light whose wavelength has been converted by the wavelength converter.

[0015] A medical system according to a third aspect of the present invention includes the light emitting device according to the second aspect.

[0016] An electronic device according to a fourth aspect of the present invention includes the light emitting device according to the first aspect.

[0017] A fifth aspect of the inspection method of the present invention uses the light emitting device of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a cross-sectional view schematically showing an example of the wavelength converter according to the present embodiment.

[0019] Figure 2 This is an example of the excitation spectrum and fluorescence spectrum of the first phosphor.

[0020] Figure 3 This is an example of the excitation spectrum and fluorescence spectrum of the second phosphor.

[0021] Figure 4 It is a cross-sectional view schematically showing another example of the wavelength converter according to the present embodiment.

[0022] Figure 5 It is a cross-sectional view schematically showing another example of the wavelength converter according to the present embodiment.

[0023] Figure 6 It is a cross-sectional view schematically showing another example of the wavelength converter according to the present embodiment.

[0024] Figure 7 It is a cross-sectional view schematically showing an example of the light emitting device according to this embodiment.

[0025] Figure 8 It is a cross-sectional view schematically showing another example of the light emitting device according to the present embodiment.

[0026] Fig. 9 It is a diagram schematically showing the structure of the endoscope according to the present embodiment.

[0027] Fig.10 is a schematic diagram showing an example of an image sensor.

[0028] Fig.11 It is a diagram schematically showing the configuration of an endoscope system according to the present embodiment.

[0029] Fig.12 This is the spectrum of light emitted by the wavelength converter of Example 1.

[0030] Fig.13 This is the spectrum of light emitted by the wavelength converter of Example 2. DETAILED DESCRIPTION

[0031] Hereinafter, the wavelength converter of the present embodiment and the light emitting device, medical system, electronic device and inspection method using the wavelength converter will be described with reference to the drawings. In addition, for the sake of convenience of description, the dimensional ratios of the drawings are exaggerated and may be different from the actual ratios.

[0032] [Wavelength converter]

[0033] like Figure 1As shown, the wavelength converter 1 of this embodiment includes a first phosphor 2 and a second phosphor 3. The first phosphor 2 is Cr 3+ The second phosphor 3 is activated by Ce 3+ and Eu 2+ A phosphor activated by at least any one of the ions.

[0034] Figure 2 is an example of the excitation spectrum and fluorescence spectrum of the first phosphor 2. Figure 2 As shown, the first phosphor 2 strongly absorbs light in the blue wavelength region of 400 nm to less than 500 nm and in the orange to red wavelength region of 580 nm to less than 660 nm. Furthermore, the first phosphor 2 absorbs blue light and orange to red light and converts the wavelengths thereof, thereby emitting near-infrared fluorescence of 680 nm to less than 800 nm.

[0035] Figure 3 is an example of the excitation spectrum and fluorescence spectrum of the second phosphor 3. The fluorescence spectrum of the fluorescence emitted by the second phosphor 3 has a peak with a maximum fluorescence intensity in the wavelength range of 500 nm to less than 580 nm. Specifically, Figure 3 As shown, the fluorescence spectrum of the fluorescence emitted by the second phosphor 3 includes a green to yellow fluorescence component in a wavelength range of 500 nm to less than 580 nm as a main fluorescence component, and has a broad fluorescence component including a blue fluorescence component and an orange to red fluorescence component.

[0036] As described above, the wavelength converter 1 includes the first phosphor 2 and the second phosphor 3. Therefore, the blue and orange to red fluorescent components emitted by the second phosphor 3 are absorbed by the first phosphor 2 and wavelength-converted into near-infrared fluorescent components.

[0037] As a result, the intensity of the blue and orange to red fluorescence components within the wide fluorescence components emitted by the second phosphor 3 decreases, and the intensity of the green to yellow fluorescence components emitted by the second phosphor 3 becomes relatively large. In particular, the intensity of the deep red fluorescence component within the wide fluorescence components emitted by the second phosphor 3 decreases. On the other hand, since the first phosphor 2 emits near-infrared fluorescence, the intensity of the near-infrared fluorescence component emitted by the wavelength converter 1 increases.

[0038] That is, in the light emitted by the wavelength converter 1, the intensity of the green to yellow and near-infrared fluorescent components increases, and the intensity of the orange to red fluorescent components decreases. Therefore, the wavelength converter 1 emits wavelength-converted light in which the green to yellow fluorescent components and the near-infrared fluorescent components are fully separated. In addition, the wavelength converter 1 emits wavelength-converted light in which the intensity of the deep red fluorescent component that becomes noise of the infrared image sensor is relatively small.

[0039] The green to yellow fluorescent component emitted by the wavelength converter 1 can be used as a light component that facilitates visual observation of the patient's affected part. The near-infrared fluorescent component emitted by the wavelength converter 1 can be used as a light component that facilitates the excitation of a fluorescent drug administered into a living body. Therefore, the wavelength converter 1 is suitable for both normal observation using visible light and special observation using near-infrared light.

[0040] The wavelength converter 1 emits fluorescence having light components in the entire wavelength range of 500 nm to less than 580 nm. By causing the wavelength converter 1 to emit such fluorescence, green to yellow fluorescence components that are useful for visual inspection of the patient's affected part can be effectively emitted. The fluorescence emitted by the wavelength converter 1 may have light components in the entire wavelength range of 500 nm to less than 600 nm.

[0041] The wavelength converter 1 emits light of a spectrum in which the ratio of the minimum luminous intensity to the maximum luminous intensity is 40% or less in the wavelength range of 550nm to 700nm. In addition, the ratio of the minimum luminous intensity to the maximum luminous intensity is 30% or less, more preferably 20% or less, further preferably 10% or less, and particularly preferably 5% or less. In this way, the wavelength converter 1 can emit wavelength-converted light in which the green to yellow fluorescent components and the near-infrared fluorescent components are further separated. The wavelength with the highest luminous intensity can be greater than 550nm and less than 580nm. The wavelength with the lowest luminous intensity can be 580nm to 700nm, or 600nm to 700nm.

[0042] The fluorescence emitted by the first phosphor 2 preferably has a light component in the entire wavelength range of 700nm to 800nm, and more preferably has a light component in the entire wavelength range of 750nm to 800nm. In this way, even if a drug whose light absorption characteristics of near-infrared light are easily deviated is used, the wavelength converter 1 can emit near-infrared excitation light that can excite the drug with good efficiency. Therefore, a light-emitting device 10 with a large amount of near-infrared light emitted by a fluorescent drug or a large amount of heat rays emitted by a photosensitizing drug can be obtained.

[0043] The fluorescence spectrum of the fluorescence emitted by the first phosphor 2 preferably has a peak showing a maximum fluorescence intensity in a wavelength range of 710 nm or more. In this way, the wavelength converter 1 can emit a large amount of fluorescence containing near-infrared light components with high biological permeability. In addition, the fluorescence spectrum of the fluorescence emitted by the first phosphor 2 may have a peak showing a maximum fluorescence intensity in a wavelength range of 710 nm to 900 nm.

[0044] It is preferred that the fluorescence emitted by the first phosphor 2 includes Cr-based 3+The fluorescence of the first phosphor 2 is the fluorescence of the electron energy transition, and the fluorescence spectrum of the fluorescence emitted by the first phosphor 2 has a peak with a maximum fluorescence intensity in the wavelength region exceeding 720nm. In this way, the first phosphor 2 can emit fluorescence with a short afterglow and a wide spectrum component more dominant than the long afterglow linear spectrum component. As a result, the wavelength converter 1 can emit a large amount of light containing near-infrared components. In addition, the linear spectrum component is based on Cr 3+ of 2 E→ 4 A2(t2 3 ) and has a peak with a maximum fluorescence intensity in the wavelength region of 680nm to 720nm. The broad spectral component is based on Cr 3+ of 4 T2(t2 2 e) → 4 A2(t2 3 ) and has a peak at which the fluorescence intensity shows a maximum value in a wavelength region exceeding 720 nm.

[0045] The fluorescence spectrum of the fluorescence emitted by the first phosphor 2 more preferably has a peak showing a maximum fluorescence intensity in a wavelength region exceeding 730 nm, and further preferably has a peak showing a maximum fluorescence intensity in a wavelength region exceeding 750 nm.

[0046] The 1 / 10 afterglow time of the fluorescence emitted by the first phosphor 2 is preferably less than 1ms, more preferably less than 300μs, and even more preferably less than 100μs. Thus, even when the light density of the excitation light that excites the first phosphor 2 is high, the output of the fluorescence emitted by the first phosphor 2 becomes less likely to be saturated. Therefore, a wavelength converter 1 capable of emitting high-output near-infrared light can be obtained. In addition, the 1 / 10 afterglow time refers to the time τ required from the time when the maximum luminous intensity is displayed to the time when the intensity becomes 1 / 10 of the maximum luminous intensity. 1 / 10 .

[0047] The 1 / 10 afterglow time of the fluorescence emitted by the first phosphor 2 is preferably longer than the 1 / 10 afterglow time of the fluorescence emitted by the second phosphor 3. Specifically, the 1 / 10 afterglow time of the fluorescence emitted by the first phosphor 2 is preferably 10 μs or more. 3+ The 1 / 10 afterglow time of the fluorescence emitted by the activated first phosphor 2 is shorter than that based on Ce. 3+ 、Eu 2+ The fluorescence of the short afterglow (less than 10 μs) of the parity-allowed transition is 1 / 10 of the afterglow time. This is because the fluorescence emitted by the first phosphor 2 is a Cr-based fluorescence with a relatively long afterglow time.3+ Fluorescence of the spin-allowed type of electronic energy transition.

[0048] The 1 / 10 afterglow time difference, which is the difference between the 1 / 10 afterglow time of the fluorescence emitted by the first phosphor 2 and the 1 / 10 afterglow time of the fluorescence emitted by the second phosphor 3, is preferably greater than 50 μs. As a result, the intensity of the visible light fluorescence component emitted by the second phosphor 3 as the main component is greatly reduced, and the near-infrared fluorescence component emitted by the first phosphor 2 as the main component also maintains a large intensity. Therefore, the afterglow time difference can be used to control the output ratio of the near-infrared fluorescence component to the visible light fluorescence component. In addition, the 1 / 10 afterglow time difference is preferably less than 1 ms.

[0049] In the fluorescence spectrum of the fluorescence emitted by the first phosphor 2, the spectral width at an intensity of 80% of the maximum fluorescence intensity is preferably greater than 20 nm and less than 80 nm. In this way, the main component of the fluorescence emitted by the first phosphor 2 becomes a wide spectral component. Therefore, in a medical field using fluorescence imaging or photodynamic therapy (PDT), even if there is a deviation in the wavelength dependence of the sensitivity of fluorescent drugs or photosensitizers, the wavelength converter 1 can emit high-output near-infrared light that allows these drugs to fully function.

[0050] In the fluorescence spectrum of the fluorescence emitted by the first phosphor 2, the ratio of the fluorescence intensity at a wavelength of 780nm to the maximum fluorescence intensity is preferably greater than 30%. The ratio of the fluorescence intensity at a wavelength of 780nm to the maximum fluorescence intensity is more preferably greater than 60%, and further preferably greater than 80%. In this way, the first phosphor 2 can emit a large amount of fluorescence containing a near-infrared wavelength region (650 to 1000nm) called a "biological window" where light easily passes through a living body. Therefore, according to such a wavelength converter 1, the intensity of near-infrared light passing through a living body can be increased.

[0051] The fluorescence spectrum of the fluorescence emitted by the first phosphor 2 preferably does not contain any residue derived from Cr. 3+ That is, the fluorescence emitted by the first phosphor 2 preferably has only a broad spectral component (short afterglow) including a peak at which the fluorescence intensity shows a maximum value in a wavelength region exceeding 720 nm. In this way, the first phosphor 2 does not contain Cr-based 3+ The long-lasting fluorescence component of the spin-forbidden transition of the first phosphor 2 is eliminated, and only the short-lasting fluorescence component based on the spin-allowed transition is included. As a result, even when the light density of the excitation light that excites the first phosphor 2 is high, the output of the fluorescence emitted by the first phosphor 2 becomes less likely to be saturated. Therefore, a light-emitting device that is a point light source capable of emitting higher-output near-infrared light can be obtained.

[0052] The first phosphor 2 preferably contains no content other than Cr 3+ In this way, the light absorbed by the first phosphor 2 is only converted into Cr-based 3+ Since the fluorescence is generated by electron energy transition, it is possible to obtain a wavelength converter 1 that can easily be designed to output light that can maximize the output ratio of the near-infrared fluorescence component.

[0053] The first phosphor 2 also preferably contains two or more Cr 3+ Thus, at least the output light component in the near-infrared wavelength region can be controlled, so that the wavelength converter 1 can be obtained in which the spectral distribution can be easily adjusted according to the application using the near-infrared fluorescent component.

[0054] The first phosphor 2 is preferably an oxide-based phosphor, and more preferably an oxide phosphor. In addition, an oxide-based phosphor refers to a phosphor containing oxygen but not nitrogen or sulfur. The oxide-based phosphor may include at least one selected from oxides, composite oxides, and compounds containing oxygen and halogen as anions.

[0055] Since oxides are stable in the atmosphere, even when the oxide phosphor generates heat due to high-density light excitation based on laser, it is not easy to cause the phosphor crystal to deteriorate due to oxidation by the atmosphere as occurs in nitride phosphors. Therefore, when all the phosphors included in the wavelength converter 1 are oxide phosphors, a light-emitting device with high reliability can be obtained.

[0056] The first phosphor 2 preferably has a garnet crystal structure. The first phosphor 2 is also preferably an oxide phosphor having a garnet crystal structure. Garnet phosphors are easy to deform and can provide a large amount of phosphor compounds, so Cr 3+ The crystal field adjustment around Cr 3+ The hue of the fluorescence is controlled by the electronic energy transitions.

[0057] In addition, phosphors having a garnet structure, especially oxides, have a polyhedral particle shape that is approximately spherical, and the dispersibility of the phosphor particle group is excellent. Therefore, when the phosphor included in the wavelength converter 1 has a garnet structure, it becomes relatively easy to manufacture a wavelength converter 1 with excellent light transmittance, and it is possible to achieve high output of the light-emitting device. In addition, since phosphors having a garnet crystal structure have practical performance as phosphors for LEDs, by making the first phosphor 2 have a garnet crystal structure, a light-emitting device with high reliability can be obtained.

[0058] The first phosphor 2 may include, for example, a material selected from Lu2CaMg2(SiO4)3:Cr 3+、Y3Ga2(AlO4)3:Cr 3+ 、Y3Ga2(GaO4)3:Cr 3+ 、Gd3Ga2(AlO4)3:Cr 3+ 、Gd3Ga2(GaO4)3:Cr 3+ 、(Y,La)3Ga2(GaO4)3:Cr 3+ 、(Gd,La)3Ga2(GaO4)3:Cr 3+ 、Ca2LuZr2(AlO4)3:Cr 3+ 、Ca2GdZr2(AlO4)3:Cr 3+ 、Lu3Sc2(GaO4)3:Cr 3+ 、Y3Sc2(AlO4)3:Cr 3+ 、Y3Sc2(GaO4)3:Cr 3+ 、Gd3Sc2(GaO4)3:Cr 3+ 、La3Sc2(GaO4)3:Cr 3+ 、Ca3Sc2(SiO4)3:Cr 3 + 、Ca3Sc2(GeO4)3:Cr 3+ 、BeAl2O4:Cr 3+ 、LiAl5O8:Cr 3+ 、LiGa5O8:Cr 3+ 、Mg2SiO4:Cr 3+ ,Li + 、La3Ga5GeO 14 :Cr 3+ and La3Ga 5.5 Nb 0.5 O 14 :Cr 3+ At least one phosphor among the above.

[0059] As described above, the fluorescence emitted by the first phosphor 2 has a Cr-based 3+ Thus, according to the wavelength converter 1, a fluorescent agent such as ICG and a photosensitive agent such as phthalocyanine (also a fluorescent agent) can be efficiently excited.

[0060] The second phosphor 3 is Ce 3+ and Eu 2+ However, the second phosphor 3 is preferably Ce. 3+ Activated phosphor. 3+The activated phosphor has the optical property of emitting fluorescence having a spectral shape with a long tail on the long wavelength side. Therefore, the light emitted by the second phosphor 3 has a large proportion of orange to red fluorescence components, which is conducive to exciting the first phosphor 2, and thus is advantageous in increasing the intensity of the near-infrared fluorescence component emitted by the first phosphor 2.

[0061] The second phosphor 3 may be at least one of an oxide-based phosphor such as an oxide and a halogen oxide, and a nitride-based phosphor such as a nitride and a nitride oxide.

[0062] The second phosphor 3 is preferably a phosphor selected from garnet type, calcium ferrite type and lanthanum silicon nitride (La3Si6N 11 Ce in which at least one of the compounds having a crystal structure of the type ) is the main component as the matrix 3+ Alternatively, the second phosphor 3 is preferably selected from garnet type, calcium ferrite type and lanthanum silicon nitride (La3Si6N 11 Ce having at least one compound in a group of compounds having a crystal structure of the type ) as a matrix 3+ Activating the phosphor. By using such a second phosphor 3, it is possible to obtain output light having a large amount of green to yellow light components.

[0063] Specifically, the second phosphor 3 is preferably selected from M3RE2(SiO4)3, RE3Al2(AlO4)3, MRE2O4 and RE3Si6N 11 Ce having at least one compound as a main component as a matrix 3+ Alternatively, the second phosphor 3 is preferably selected from M3RE2(SiO4)3, RE3Al2(AlO4)3, MRE2O4 and RE3Si6N 11 Ce as a matrix of at least one 3+ Alternatively, the second phosphor 3 is preferably Ce, which is a solid solution having the compound as a terminal component as a matrix. 3+ Activate the phosphor. In addition, M is an alkaline earth metal and RE is a rare earth element.

[0064] Such a second phosphor 3 absorbs light in the wavelength range of 430nm to 480nm well, and efficiently converts it into green to yellow light having a peak with a maximum fluorescence intensity in the wavelength range of 540nm to less than 580nm. Therefore, by using such a phosphor as the second phosphor 3 on the basis of a light source 5 that emits cool light in the wavelength range of 430nm to 480nm as the primary light 6, it is possible to easily obtain a visible light component.

[0065] The wavelength converter 1 is preferably formed of an inorganic material. Here, the inorganic material refers to a material other than an organic material, and is a concept including ceramics and metals. By forming the wavelength converter 1 from an inorganic material, the thermal conductivity becomes higher than that of a wavelength converter containing an organic material such as a sealing resin, so that a high heat dissipation design becomes easy. Therefore, even in the case where the phosphor is excited at a high density by the primary light 6 emitted by the light source 5, the temperature rise of the wavelength converter 1 can be effectively suppressed. As a result, the temperature quenching of the phosphor in the wavelength converter 1 is suppressed and the light output can be increased. As a result, the heat dissipation of the phosphor is improved, so the output reduction of the phosphor caused by temperature quenching is suppressed and high-output near-infrared light can be emitted.

[0066] The wavelength converter 1 is preferably entirely made of inorganic materials. This improves the heat dissipation of the first phosphor 2 and the second phosphor 3, thereby suppressing the decrease in phosphor output due to temperature quenching and providing a light-emitting device that emits high-output near-infrared light.

[0067] At least one of the first phosphor 2 and the second phosphor 3 may be ceramic. This increases the thermal conductivity of the wavelength converter 1, thereby providing a light-emitting device 10 with high output and low heat generation. In this case, ceramic refers to a sintered body in which particles are bonded to each other.

[0068] like Figure 1 As shown, the wavelength converter 1 preferably has a sealing material 4 in which the first phosphor 2 and the second phosphor 3 are dispersed in addition to the first phosphor 2 and the second phosphor 3. In the wavelength converter 1, the first phosphor 2 and the second phosphor 3 are preferably dispersed in the sealing material 4. By dispersing the first phosphor 2 and the second phosphor 3 in the sealing material 4, the light emitted to the wavelength converter 1 can be efficiently absorbed and wavelength-converted into near-infrared light. In addition, the wavelength converter 1 can be easily formed into a sheet or a film.

[0069] The sealing material 4 is preferably at least one of an organic material and an inorganic material, in particular at least one of a transparent (light-transmitting) organic material and a transparent (light-transmitting) inorganic material. As the sealing material of the organic material, for example, a transparent organic material such as silicone resin can be listed. As the sealing material of the inorganic material, for example, a transparent inorganic material such as low-melting-point glass can be listed.

[0070] As described above, the wavelength converter 1 is preferably formed of an inorganic material, and therefore the sealing material 4 is preferably formed of an inorganic material. In addition, zinc oxide (ZnO) is preferably used as the inorganic material. As a result, the heat dissipation of the phosphor is further improved, so that the output reduction of the phosphor caused by temperature quenching is suppressed, and a wavelength converter 1 that emits high-output near-infrared light can be obtained.

[0071] In addition, Figure 1 In the embodiment, the first phosphor 2 and the second phosphor 3 are uniformly mixed and dispersed in a layer of the sealing material 4. However, the wavelength converter 1 is not limited to this embodiment. Figure 4 As shown, the wavelength converter 1 may include a first sealing material 4A and a second sealing material 4B. The first phosphor 2 may be dispersed in the first sealing material 4A and the second phosphor 3 may be dispersed in the second sealing material 4B. Figure 4 As shown, the first sealing material 4A and the second sealing material 4B may be formed into layers respectively and the layers may be stacked together in an overlapping manner. The first sealing material 4A and the second sealing material 4B may be formed of the same material or different materials.

[0072] like Figure 5 and Figure 6 As shown in FIG. 4 , the wavelength converter 1 may not use the sealing material 4. Specifically, Figure 5 As shown, the wavelength converter 1 may not have the sealing material 4 and the first phosphor 2 and the second phosphor 3 may be uniformly mixed and dispersed. Figure 6 As shown, the wavelength converter 1 can form a layer in which the first phosphor 2 and the second phosphor 3 are respectively assembled without the sealing material 4, and the layers are stacked in an overlapping manner. In this case, it is sufficient to use an organic or inorganic binder to fix the phosphors to each other. In addition, the phosphors can also be fixed to each other by the heating reaction of the phosphors. As the binder, a commonly used resin-based adhesive or ceramic particles, low-melting point glass, etc. can be used. The wavelength converter 1 without the sealing material 4 can be used for light-emitting devices because the thickness can be reduced.

[0073] [Light-emitting device]

[0074] Next, use Figure 7 and Figure 8 The light emitting device 10 of this embodiment will be described.

[0075] like Figure 7 As shown, the light emitting device 10 of this embodiment includes the wavelength converter 1 and the light source 5, and the light source 5 emits light whose wavelength is converted by the wavelength converter 1. That is, the light emitting device 10 is a light emitting device 10 composed of at least the light source 5 that emits the primary light 6, the first phosphor 2, and the second phosphor 3. The wavelength converter 1 receives the primary light 6 emitted by the light source 5, and emits fluorescence having a longer wavelength than the primary light 6. Figure 7 The light emitting device 10 shown receives the primary light 6 at the front surface 1A of the wavelength converter 1 and emits fluorescent light from the back surface 1B of the wavelength converter 1 .

[0076] The emitted fluorescence includes the first wavelength converted light 7 and the second wavelength converted light 8. The second wavelength converted light 8 is the fluorescence emitted by converting the wavelength of a part of the primary light 6 absorbed by the second phosphor 3. The first wavelength converted light 7 is the fluorescence emitted by converting the wavelength of a part of the primary light 6 and / or the second wavelength converted light 8 absorbed by the first phosphor 2. The first wavelength converted light 7 has a wavelength conversion factor based on Cr 3+ The specific fluorescent component of the electron energy transition, so the light-emitting device 10 can emit Cr-based 3+ Fluorescence due to electronic energy transitions.

[0077] As described above, the wavelength converter 1 emits wavelength converted light in which the green to yellow fluorescent component and the near-infrared fluorescent component are fully separated. Therefore, the light-emitting device 10 as described above emits output light in which the green to yellow fluorescent component and the near-infrared fluorescent component are fully separated. In addition, the green to yellow fluorescent component can be used as a light component that is conducive to visual observation of the patient's affected part. On the other hand, the near-infrared fluorescent component can be used as a light component that is conducive to exciting a drug applied to a living body. Therefore, the light-emitting device 10 can take into account both the normal observation using visible light and the special observation using near-infrared light, which is conducive to diagnosis.

[0078] As described above, the light source 5 emits light converted by the wavelength converter 1, and the light emitted by the light source 5 is preferably laser. Laser is a point light source with strong directivity and high output, so it is possible to achieve not only miniaturization of the optical system and reduction of the diameter of the light guide, but also improve the efficiency of combining the laser with the optical fiber. Therefore, a light-emitting device 10 that can be easily increased in output can be obtained. From the perspective of miniaturization of the light-emitting device 10, the laser is preferably emitted by a semiconductor light-emitting element.

[0079] The spectrum of the light emitted by the light source 5 preferably has a peak with a maximum intensity in a wavelength range of 400 nm to less than 500 nm. The spectrum of the light emitted by the light source 5 preferably has a peak with a maximum intensity in a wavelength range of 420 nm to less than 480 nm, and the light emitted by the light source 5 is blue light. The spectrum of the light emitted by the light source 5 more preferably has a peak with a maximum intensity in a wavelength range of 430 nm to less than 480 nm, and further preferably has a peak with a maximum intensity in a wavelength range of 440 nm to less than 470 nm. In this way, not only can the Cr-excited light be efficiently excited, but also the Cr-excited light can be excited efficiently. 3+ The activated first phosphor 2 can also be used as a high-efficiency phosphor with high performance in LED lighting. 3+ and Eu 2+ The second phosphor 3 is activated by at least any one of the above. Therefore, a high-output light-emitting device 10 can be obtained.

[0080] The light source 5 may include a red laser element or a blue laser element. The energy difference between the red laser element and the near-infrared light component is small, and the energy loss accompanying the wavelength conversion is small, so it is preferred in terms of achieving high efficiency of the light-emitting device 10. On the other hand, as for the blue laser element, since it is easy to obtain high-efficiency and high-output laser elements, it is preferred in terms of achieving high output of the light-emitting device 10. In addition, the light source 5 preferably includes a blue laser element as an excitation source and radiates blue laser light. As a result, the first phosphor 2 and the second phosphor 3 are excited with high efficiency and high output, so that the light-emitting device 10 can radiate high-output near-infrared light.

[0081] Preferably, the light source 5 includes a solid light emitting element and the blue light is emitted by the solid light emitting element. In this way, a small light emitting element with high reliability can be used as the light source of the blue light, so that a small light emitting device 10 with high reliability can be obtained.

[0082] The solid-state light emitting element is a light emitting element that emits the primary light 6. As long as the solid-state light emitting element can emit the primary light 6 with high energy density, all light emitting elements can be used. In addition, the solid-state light emitting element is preferably at least one of a laser element and a light emitting diode (LED), and more preferably a laser element. The light source 5 may also be, for example, a surface emitting laser diode or the like.

[0083] The rated light output of the solid-state light emitting element is preferably 1 W or more, and more preferably 3 W or more. Thus, the light source 5 can emit high-output primary light 6, and thus a light emitting device 10 that can easily increase output can be obtained.

[0084] The upper limit of the rated light output is not particularly limited, and the rated light output can be increased by providing the light source 5 with a plurality of solid-state light emitting elements. However, in consideration of practical feasibility, the rated light output is preferably less than 10 kW, and more preferably less than 3 kW.

[0085] The optical density of the primary light 6 is preferably greater than 0.5 W / mm 2 , more preferably more than 3W / mm 2 , more preferably more than 10W / mm 2 . The optical density can also exceed 30W / mm 2 In this way, the first phosphor 2 and the second phosphor 3 are excited by light at a high density, so that the wavelength converter 1 can emit a high-output fluorescent component.

[0086] The primary light 6 is preferably a continuous pulse light. In this way, immediately after the pulse light is turned off (OFF), the first wavelength converted light 7 having a near-infrared fluorescent component emits phosphorescence for a longer period of time than the second wavelength converted light 8 that becomes visible light. By using the phosphorescent component as the excitation light for the above-mentioned drug, it is possible to obtain a light emitting device 10 that is easy to design so that only the near-infrared fluorescent component emitted by the drug is incident on the image sensor and the second wavelength converted light 8 is not incident on the image sensor. Therefore, it is possible to obtain a light emitting device 10 that is advantageous in improving the S / N ratio of the near-infrared fluorescent component emitted by the drug.

[0087] The correlated color temperature of the mixed light of the primary light 6 and the second wavelength converted light 8 is preferably 2500K or more and less than 7000K. The correlated color temperature is more preferably 2700K or more and less than 5500K, and further preferably 2800K or more and less than 3200K or 4500K or more and less than 5500K. The output light having a correlated color temperature within the above range is white output light, so that the affected part that can be visually confirmed by an image display device or an optical device looks similar to the affected part observed under natural light. Therefore, the light emitting device 10 that is preferred as a medical device that allows doctors to easily make full use of their medical experience can be obtained.

[0088] Next, the operation of the light emitting device 10 of this embodiment will be described. Figure 7 In the light emitting device 10 shown, the primary light 6 emitted by the light source 5 is first irradiated toward the front surface 1A of the wavelength converter 1. Most of the irradiated primary light 6 enters the wavelength converter 1 from the front surface 1A of the wavelength converter 1 and passes through the wavelength converter 1, and a part of the irradiated primary light 6 is reflected by the surface of the wavelength converter 1. The second phosphor 3 absorbs a part of the primary light 6 and converts it into the second wavelength converted light 8, and the first phosphor 2 absorbs a part of the primary light 6 and / or the second wavelength converted light 8 and converts it into the first wavelength converted light 7. In this way, the light emitting device 10 irradiates light including the primary light 6, the first wavelength converted light 7, and the second wavelength converted light 8 from the back surface 1B of the wavelength converter 1 as output light.

[0089] In addition, the light emitting device 10 is not limited to Figure 7 The methods shown are not limited to the following methods: Figure 7 As shown, the wavelength converter 1 receives the primary light 6 from the front surface 1A, and radiates the first wavelength converted light 7 and the second wavelength converted light 8 from the back surface 1B. Figure 8 As shown, the light emitting device 10 may also receive the primary light 6 from the front surface 1A of the wavelength converter 1 and emit the first wavelength converted light 7 and the second wavelength converted light 8 from the front surface 1A of the wavelength converter 1. Figure 8In the light emitting device 10 shown, the primary light 6 emitted by the light source 5 is first irradiated toward the front surface 1A of the wavelength converter 1. Most of the irradiated primary light 6 enters the wavelength converter 1 from the front surface 1A of the wavelength converter 1, and a part of the irradiated primary light 6 is reflected by the surface of the wavelength converter 1. The second phosphor 3 absorbs a part of the primary light 6 and converts it into the second wavelength converted light 8, and the first phosphor 2 absorbs a part of the primary light 6 and / or the second wavelength converted light 8 and converts it into the first wavelength converted light 7. In this way, the light emitting device 10 irradiates light including the primary light 6, the first wavelength converted light 7, and the second wavelength converted light 8 from the front surface 1A of the wavelength converter 1 as output light.

[0090] Thus, the light emitting device 10 of the present embodiment emits a large amount of light including Cr. 3+ The first wavelength converted light 7 is a near-infrared fluorescent component with a long afterglow due to the electron energy transition. The near-infrared fluorescent component can be used as a light component that is useful for exciting fluorescent drugs applied in vivo. In addition, the light emitting device 10 of this embodiment emits a large amount of Ce-based 3+ Or Eu 2+ The second wavelength converted light 8 is a short-lasting green to yellow fluorescent component of the electron energy transition. The green to yellow fluorescent component can be used as a light component that facilitates visual inspection of the affected part of the patient.

[0091] Therefore, the light emitting device 10 can be used for medical treatment. That is, the light emitting device 10 can also be a medical light emitting device. In other words, the light emitting device 10 can be a medical lighting device. In this way, the light emitting device 10 emits output light in which the green to yellow fluorescent components and the near-infrared fluorescent components are fully separated, so that it can take into account both the normal observation and the special observation as described above, which is beneficial to the diagnosis of the disease.

[0092] The light emitting device 10 can also be used for optical coherence tomography (OCT) and the like. However, the light emitting device 10 is preferably used for any method in fluorescence imaging or photodynamic therapy. The light emitting device 10 used for these methods is a light emitting device for a medical system that utilizes drugs such as fluorescent agents and photosensitizers. These methods are medical technologies that are expected to have a wide range of applications and are highly practical. These light emitting devices 10 irradiate the interior of a living body with wide, high-output near-infrared light through a "biological window", enabling the fluorescent agents and photosensitizers introduced into the body to fully function, and therefore a large therapeutic effect can be expected.

[0093] Fluorescence imaging is a method described as follows: a fluorescent agent that selectively binds to a lesion such as a tumor is applied to the subject, and then the fluorescent agent is excited by specific light, and the fluorescence emitted by the fluorescent agent is detected and imaged by an image sensor, thereby observing the lesion. According to the fluorescence imaging method, lesions that are difficult to observe can be observed only with normal lighting. As a fluorescent agent, an agent that absorbs excitation light in the near-infrared light region and further emits fluorescence in the near-infrared light region with a wavelength longer than that of the excitation light can be used. As a fluorescent agent, for example, at least one of indocyanine green (ICG), phthalocyanine compounds, sodium talaporfin compounds, and dipicolylcyanine (DIPCY) compounds can be used.

[0094] Photodynamic therapy is a treatment method in which a photosensitive agent that selectively binds to a target biological tissue is applied to a subject, and then near-infrared rays are irradiated to the photosensitive agent. When near-infrared rays are irradiated to the photosensitive agent, active oxygen is generated from the photosensitive agent, thereby treating lesions such as tumors and infections. As the photosensitive agent, for example, at least one selected from phthalocyanine compounds, talaporfin sodium compounds, and porfimer sodium compounds can be used.

[0095] The light emitting device 10 of this embodiment can also be made into a light source for a sensing system or a lighting system for a sensing system. In the light emitting device 10, a conventional light receiving element having light receiving sensitivity in the near-infrared wavelength region can be used to form a highly sensitive sensing system. Therefore, a light emitting device that can easily miniaturize the sensing system and expand the sensing range can be obtained.

[0096] [Medical System]

[0097] Next, a medical system including the above-mentioned light emitting device 10 will be described. Specifically, as an example of a medical system, Figures 9 to 11 An endoscope 11 including the light emitting device 10 and an endoscope system 100 using the endoscope 11 will be described.

[0098] (Endoscope)

[0099] like Fig. 9 As shown, the endoscope 11 of this embodiment includes the above-mentioned light emitting device 10. The endoscope 11 includes a scope 110, a light source connector 111, a mounting adapter 112, a relay lens 113, a camera head 114, and an operation switch 115.

[0100] The mirror 110 is a thin and long light-guiding member that can guide light from the end to the front end, and is inserted into the body when used. The mirror 110 has an imaging window 110z at the front end, and an optical material such as optical glass or optical plastic is used in the imaging window 110z. The mirror 110 has an optical fiber that guides the light introduced by the light source connector 111 to the front end and an optical fiber that transmits the optical image injected from the imaging window 110z.

[0101] The light source connector 111 introduces illumination light from the light emitting device 10 to illuminate the affected part in the body. In this embodiment, the illumination light includes visible light and near infrared light. The light introduced into the light source connector 111 is guided to the front end of the mirror 110 via the optical fiber and illuminates the affected part in the body through the imaging window 110z. Fig. 9 As shown, a transmission cable 111z for guiding illumination light from the light emitting device 10 to the mirror 110 is connected to the light source connector 111. The transmission cable 111z may also include an optical fiber.

[0102] The mount adapter 112 is a member for mounting the mirror 110 on the camera 114. Various mirrors 110 are detachably mounted on the mount adapter 112.

[0103] The relay lens 113 focuses the optical image transmitted from the mirror 110 onto the imaging surface of the image sensor. In addition, the relay lens 113 can move the lens according to the operation amount of the operation switch 115 to adjust the focus and magnification.

[0104] The camera 114 has a dichroic prism inside. The dichroic prism decomposes the light focused by the relay lens 113 into four colors: R light (red light), G light (green light), B light (blue light), and IR light (near infrared light). The dichroic prism is made of a light-transmitting member such as glass.

[0105] Furthermore, the camera 114 has an image sensor 114A as a detector inside. The image sensor 114A is not particularly limited, and at least one of a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor) can be used. The image sensor 114A can include a variety of image sensors.

[0106] For example, Fig.10As shown, the image sensor 114A may include an IR light image sensor 114IR and a visible light image sensor 114V. The visible light image sensor 114V may include an R light image sensor 114R, a G light image sensor 114G, and a B light image sensor 114B. The IR light image sensor 114IR is a dedicated sensor for receiving light of an IR component (near infrared component). The R light image sensor 114R is a dedicated sensor for receiving light of an R component (red component). The G light image sensor 114G is a dedicated sensor for receiving light of a G component (green component). The B light image sensor 114B is a dedicated sensor for receiving light of a B component (blue component). The IR light image sensor 114IR, the R light image sensor 114IR, the G light image sensor 114G, and the B light image sensor 114B convert optical images formed on respective imaging surfaces into electrical signals.

[0107] The camera 114 may also have a color filter inside instead of the dichroic prism. A color filter is provided on the imaging surface of the image sensor 114A. For example, four color filters are provided, and the four color filters receive the light focused by the relay lens 113 and selectively transmit R light (red light), G light (green light), B light (blue light), and IR light (near infrared light).

[0108] The color filter that selectively transmits IR light preferably includes a blocking film that cuts off the reflected component of near-infrared light (IR light) included in the illumination light. Thus, for example, only the fluorescence including IR light emitted by a fluorescent agent such as ICG is imaged on the imaging surface of the IR light image sensor 114IR. Therefore, it becomes easy to clearly observe the affected part that is illuminated by the fluorescent agent.

[0109] In addition, if Fig. 9 As shown, the camera 114 is connected to a signal cable 114z for transmitting an electrical signal from the image sensor 114A to the CCU 12 described later.

[0110] In the endoscope 11 configured in this manner, light from the subject passes through the mirror 110 and is guided to the relay lens 113 , and then passes through a dichroic prism in the camera head 114 to form an image on four image sensors.

[0111] (Endoscope System)

[0112] like Fig.11 As shown, the endoscope system 100 includes an endoscope 11 for capturing images inside a subject, a CCU (Camera Control Unit) 12 , and a display device 13 such as a monitor.

[0113] The CCU 12 includes at least an RGB signal processing unit, an IR signal processing unit, and an output unit. The CCU 12 implements the functions of the RGB signal processing unit, the IR signal processing unit, and the output unit by executing a program stored in a memory inside or outside the CCU 12 .

[0114] The RGB signal processing unit converts the electrical signals of the R component, G component, and B component from the visible light image sensor 114V into image signals that can be displayed on the display device 13 and outputs them to the output unit. In addition, the IR signal processing unit converts the electrical signal of the IR component from the IR light image sensor 114IR into an image signal and outputs it to the output unit.

[0115] The output unit outputs at least one of the image signals of the RGB color components and the image signal of the IR component to the display device 13. For example, the output unit outputs the image signal based on any one of the synchronous output mode and the superimposed output mode.

[0116] In the synchronous output mode, the output unit synchronously outputs the RGB image and the IR image through different screens. In the synchronous output mode, the RGB image and the IR image can be compared on different screens to observe the affected part. In the overlap output mode, the output unit outputs a composite image in which the RGB image and the IR image are overlapped. In the overlap output mode, for example, the affected part illuminated by ICG can be clearly observed in the RGB image.

[0117] The display device 13 displays an image of an object such as an affected part on a screen based on an image signal from the CCU 12. In the case of the synchronous output mode, the display device 13 divides the screen into a plurality of parts, and displays the RGB image and the IR image in parallel on each screen. In the case of the overlapped output mode, the display device 13 displays a composite image formed by overlapping the RGB image and the IR image on one screen.

[0118] Next, the functions of the endoscope 11 and the endoscope system 100 of this embodiment are described. When observing a subject using the endoscope system 100, indocyanine green (ICG) as a fluorescent substance is first applied to the subject. As a result, ICG accumulates in sites (affected areas) such as lymph nodes and tumors.

[0119] Next, visible light and near-infrared light are introduced from the light emitting device 10 to the light source connector 111 through the transmission cable 111z. The light introduced into the light source connector 111 is guided to the front end side of the mirror 110, projected from the imaging window 110z, and thereby irradiates the affected part and the surrounding area of ​​the affected part. The light reflected by the affected part and the fluorescence emitted by ICG are guided to the rear end side of the mirror 110 through the imaging window 110z and the optical fiber, and are focused by the relay lens 113 and incident on the dichroic prism inside the camera 114.

[0120] As for the color separation prism, the IR component light separated by the IR separation prism among the incident light is imaged as an optical image of the infrared light component by the IR light image sensor 114IR. The R component light separated by the red color separation prism is imaged as an optical image of the red component by the R light image sensor 114R. The G component light separated by the green color separation prism is imaged as an optical image of the green component by the G light image sensor 114G. The B component light separated by the blue color separation prism is imaged as an optical image of the blue component by the B light image sensor 114B.

[0121] The electric signal of the IR component converted by the IR light image sensor 114IR is converted into an image signal by the IR signal processing unit in the CCU 12. The electric signals of the R component, the G component, and the B component respectively converted by the visible light image sensor 114V are converted into image signals by the RGB signal processing unit in the CCU 12. The image signal of the IR component and the image signals of the R component, the G component, and the B component are synchronously output to the display device 13.

[0122] When the synchronous output mode is set in CCU 12, the RGB image and the IR image are synchronously displayed on two screens of the display device 13. In addition, when the overlap output mode is set in CCU 12, the display device 13 displays a composite image formed by overlapping the RGB image and the IR image.

[0123] As described above, the endoscope 11 of the present embodiment includes the light emitting device 10. Therefore, by using the endoscope 11 to efficiently excite the fluorescent agent to emit light, the affected part can be clearly observed.

[0124] The endoscope 11 of the present embodiment preferably further includes a detector for detecting the fluorescence emitted by the fluorescent agent that absorbs the first wavelength converted light 7. Specifically, the endoscope 11 preferably includes the image sensor 114A as described above. The endoscope 11 further includes a detector for detecting the fluorescence emitted by the fluorescent agent in addition to the light emitting device 10, thereby enabling the endoscope 11 to identify the affected part alone. Therefore, it is not necessary to perform a large abdominal incision as in the past to identify the affected part, thereby enabling diagnosis and treatment with less burden on the patient. In addition, the doctor using the endoscope 11 can accurately grasp the affected part, thereby improving the treatment efficiency.

[0125] The medical system is preferably used for any method in fluorescence imaging or photodynamic therapy. The medical systems used in these methods are medical technologies that are expected to have a wide range of applications and are highly practical. These medical systems can fully function after the fluorescent drugs and photosensitizers introduced into the body by irradiating the inside of the body with a wide near-infrared high-output light through the "biological window", thereby achieving a great therapeutic effect. In addition, since such a medical system uses a light-emitting device 10 with a relatively simple structure, it is conducive to miniaturization and low cost.

[0126] The medical system further includes a first image sensor and a second image sensor in addition to the light emitting device 10. The first image sensor can detect the reflected light of the visible light component emitted by the light emitting device 10. The second image sensor can detect the near-infrared fluorescent component emitted by the medicine. The medicine is excited by the light emitted by the light emitting device 10. The first image sensor is, for example, the visible light image sensor 114V described above. The second image sensor is, for example, the IR light image sensor 114IR described above. The medicine is, for example, the fluorescent medicine described above.

[0127] In this way, it is easy to assign the image of the appearance of the affected part of the living body and the state observation of the near-infrared fluorescent component emitted by the drug (fluorescent protein) applied to the living body to the first image sensor and the second image sensor respectively. Such a medical system can take into account both normal observation and special observation and is conducive to disease diagnosis.

[0128] [Electronic equipment]

[0129] Next, the electronic device of this embodiment is described. The electronic device of this embodiment includes a light emitting device 10. As described above, the light emitting device 10 can enhance the therapeutic effect and facilitate the miniaturization of the sensing system. The electronic device of this embodiment uses the light emitting device 10, so if it is used for medical equipment or sensing equipment, it can enhance the therapeutic effect and miniaturize the sensing system.

[0130] The electronic device, for example, includes a light emitting device 10 and a light receiving element. The light receiving element is, for example, a sensor such as an infrared sensor that detects light in the near-infrared wavelength region. The electronic device may be any of an information recognition device, a discrimination device, a detection device, or a testing device. As described above, these devices can also easily realize the miniaturization of the sensing system and the expansion of the sensing range.

[0131] The information recognition device is, for example, a driving support system that detects a reflected component of emitted infrared light and recognizes surrounding conditions.

[0132] The distinguishing device is, for example, a device that distinguishes a predetermined illuminated object by utilizing the difference in infrared light components between the irradiating light and the reflected light reflected by the illuminated object.

[0133] The detection device is, for example, a device for detecting liquids. Examples of liquids include water and flammable liquids that are prohibited from being transported by aircraft. Specifically, the detection device may be a device for detecting water attached to glass and water absorbed by objects such as sponges and micropowders. The detection device may visualize the detected liquid. Specifically, the detection device may visualize the distribution information of the detected liquid.

[0134] The inspection device may be any of a medical inspection device, an agricultural and animal husbandry inspection device, a fishery inspection device, or an industrial inspection device, and these devices are useful for inspecting inspection objects in various industries.

[0135] Medical testing devices are, for example, testing devices for testing the health status of humans or animals other than humans. Animals other than humans are, for example, livestock. Medical testing devices are, for example, devices for testing organisms such as fundus examination and blood oxygen saturation examination, and devices for testing organs such as blood vessels and internal organs. Medical testing devices can be devices for testing the inside of a living body, or devices for testing the outside of a living body.

[0136] The inspection device for agriculture and animal husbandry is, for example, a device for inspecting agricultural and animal husbandry products including agricultural products and livestock products. Agricultural products may be, for example, products used as food such as fruits and vegetables and cereals, or may be used as fuel such as oil. Livestock products may be, for example, edible meat and dairy products. The inspection device for agriculture and animal husbandry may be a device for non-destructively inspecting the inside or outside of agricultural and animal husbandry products. The inspection device for agriculture and animal husbandry is, for example, a device for inspecting the sugar content of fruits and vegetables, a device for inspecting the sourness of fruits and vegetables, a device for inspecting the freshness of fruits and vegetables by visualizing leaf veins, a device for inspecting the quality of fruits and vegetables by visualizing scars and internal defects, a device for inspecting the quality of edible meat, a device for inspecting the quality of processed foods obtained by processing milk and edible meat as raw materials, etc.

[0137] The inspection device for fisheries is, for example, a device for inspecting the meat quality of fish such as tuna, or a device for inspecting the presence or absence of shellfish meat in the shell of a shellfish.

[0138] Examples of industrial inspection devices include foreign matter inspection devices, content inspection devices, state inspection devices, and structure inspection devices.

[0139] Examples of foreign matter inspection devices include devices for inspecting foreign matter in liquids placed in containers such as beverages and liquid medicines, devices for inspecting foreign matter in packaging materials, devices for inspecting foreign matter in printed images, devices for inspecting foreign matter in semiconductors and electronic components, devices for inspecting foreign matter such as bone residues, garbage and engine oil in foods, devices for inspecting foreign matter in processed foods in containers, and devices for inspecting foreign matter inside medical devices such as plasters, drugs and quasi-drugs.

[0140] Examples of content inspection devices include devices for inspecting the content of liquid in containers for beverages and liquid medicines, devices for inspecting the content of processed foods in containers, and devices for inspecting the asbestos content in building materials.

[0141] The state inspection device is, for example, a device that inspects the packaging state of the packaging material and a device that inspects the printing state of the packaging material.

[0142] The inspection device for the structure is, for example, an internal non-destructive inspection device and an external non-destructive inspection device for composite members or composite components such as resin products. As a specific example of a resin product, for example, a metal brush having a portion of a metal wire buried in a resin can be used to inspect the bonding state of the resin and the metal.

[0143] Electronic devices can use color night vision technology. Color night vision technology is a technology that uses the correlation between the reflection intensity of visible light and infrared light to assign RGB signals to each wavelength of infrared light to colorize images. According to color night vision technology, color images can be obtained only with infrared light, so it is particularly suitable for crime prevention devices, etc.

[0144] As described above, the electronic device includes the light emitting device 10. The light emitting device 10 may include a power source, a light source 5, and a wavelength converter 1, and it is not necessary to accommodate all of them in one housing. Therefore, the electronic device of this embodiment can also provide an inspection method with excellent operability, high precision, and compactness.

[0145] [Test method]

[0146] Next, the inspection method of this embodiment is described. As described above, the electronic device having the light emitting device 10 can be used as an inspection device. That is, the inspection method of this embodiment can use the light emitting device 10. Thus, a highly accurate and compact inspection method with excellent operability can be provided.

[0147] Example

[0148] Hereinafter, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited to these Examples.

[0149] [Preparation of phosphor]

[0150] (Example 1)

[0151] The Cr-containing 3+ Activated phosphor and Ce 3+ The phosphor used in Example 1 is Cr 3+ The activated phosphor is composed of Y3(Ga 0.97 Cr 0.03 )2Ga3O 12 The oxide phosphor represented by the composition formula of is synthesized by using Cr in Example 1. 3+ When the activated phosphor was used, the following compound powders were used as the main raw materials.

[0152] Yttrium oxide (Y2O3): purity 3N, Shin-Etsu Chemical Co., Ltd.

[0153] Gallium oxide (Ga2O3): Purity 4N, Wako Pure Chemical Industries, Ltd.

[0154] Chromium oxide (Cr2O3): Purity 3N, Kojundo Chemical Research Institute Co., Ltd.

[0155] First, a compound Y3(Ga 0.97 Cr 0.03 )2Ga3O 12 The raw materials were weighed in a manner. Then, the weighed raw materials were put into a beaker filled with pure water and stirred for 1 hour using a magnetic stirrer. Thus, a slurry-like mixed raw material formed by pure water and the raw materials was obtained. After that, the slurry-like mixed raw material was dried in full using a dryer. Then, the dried mixed raw material was crushed using a mortar and pestle to prepare a calcined raw material.

[0156] The sintered raw materials were transferred to a small alumina crucible and sintered in an atmosphere at 1350°C to 1450°C for 1 hour using a box-type electric furnace, thereby obtaining Cr-coated 3+ The activated phosphor was set at a temperature rise and fall rate of 400°C / hour. The body color of the obtained phosphor was dark green.

[0157] The Ce used in Example 1 3+ The activated phosphor is set to (Y 0.75 G 0.22 Ce 0.03 )3Al2Al3O 12 A commercially available oxide phosphor represented by the composition formula:

[0158] The obtained Cr 3+ Activated phosphor and Ce 3+ The activated phosphors were mixed to obtain the mixed powder of Example 1. A mortar and pestle were used for mixing, and the mixing time was set to 3 minutes.

[0159] (Example 2)

[0160] The Cr-containing 3+ Activated phosphor and Ce 3+ The phosphor used in Example 2 is Cr 3+ The activated phosphor is composed of (Gd 0.75 La 0.25 )3(Ga 0.97 Cr 0.03 )2Ga3O 12 The oxide phosphor represented by the composition formula of . The Cr- 3+ When the activated phosphor was used, the following compound powders were used as the main raw materials.

[0161] Gadolinium oxide (Gd2O3): Purity 3N, Wako Pure Chemical Industries, Ltd.

[0162] Lanthanum oxide (La2O3): Purity 3N, Wako Pure Chemical Industries, Ltd.

[0163] Gallium oxide (Ga2O3): Purity 4N, Wako Pure Chemical Industries, Ltd.

[0164] Chromium oxide (Cr2O3): Purity 3N, Kojundo Chemical Research Institute Co., Ltd.

[0165] First, a compound (Gd 0.75 La 0.25 )3(Ga 0.97 Cr 0.03 )2Ga3O 12 The above raw materials were weighed in a manner. Then, the weighed raw materials were put into a beaker filled with pure water and stirred for 1 hour using a magnetic stirrer. Thus, a slurry-like mixed raw material containing pure water and raw materials was obtained. After that, the slurry-like mixed raw material was dried in full using a dryer. Then, the dried mixed raw material was crushed using a mortar and pestle to prepare a calcined raw material.

[0166] The sintered raw material was transferred to a small alumina crucible and sintered in an atmosphere at 1400°C to 1500°C for 1 hour using a box-type electric furnace, thereby obtaining a Cr-coated 3+Activated phosphor. The heating and cooling rate was set to 400°C / hour. The body color of the obtained phosphor was light green.

[0167] In Example 2, Ce 3+ The activated phosphor was set to be the commercially available LuAG phosphor (Lu3Al2Al3O 12 :Ce 3 + ). Taking the fluorescence peak wavelength into consideration, the chemical composition of the LuAG phosphor is estimated to be (Lu 0.995 Ce 0.005 )3Al2Al3O 12 .

[0168] The obtained Cr 3+ Activated phosphor and Ce 3+ The activated phosphors were mixed to obtain a mixed powder of Example 2. A mortar and pestle were used for mixing, and the mixing time was set to 3 minutes.

[0169] [evaluate]

[0170] (Crystal structure analysis)

[0171] The Cr-coated samples used in Example 1 were analyzed using an X-ray diffraction apparatus (X'Pert PRO; manufactured by Spectris plc, PANalytical). 3+ Activated phosphor and Ce 3+ The crystal structure of the activated phosphor was evaluated.

[0172] The details are omitted, but the evaluation results show that: the Cr 3+ Activated phosphor and Ce 3+ The activated phosphor is mainly composed of a compound having a garnet crystal structure. 3+ Activated phosphor and Ce 3+ The activated phosphors are all garnet phosphors.

[0173] Next, the Cr-coated 3+ Activated phosphor and Ce 3+ The crystal structure of the activated phosphor was evaluated.

[0174] Although the details are omitted, the evaluation results show that: 3+ Activated phosphor and Ce 3+The activated phosphor is mainly composed of a compound having a garnet crystal structure. 3+ Activated phosphor and Ce 3+ The activated phosphors are all garnet fluorescent.

[0175] (Spectral characteristics)

[0176] Next, the mixed powders of Example 1 and Example 2 were spread on a stainless steel cylindrical folder with a diameter of 10 mm and a depth of 1 mm to prepare a wavelength converter, and its fluorescence spectrum characteristics were evaluated. The evaluation used a quantum efficiency measurement system (QE-1100, manufactured by Otsuka Electronics Co., Ltd.) equipped with an instantaneous multi-channel photometry system (MCPD-9800, manufactured by Otsuka Electronics Co., Ltd.). In addition, the excitation wavelength was set to 450 nm.

[0177] The fluorescence spectrum of Example 1 is shown in Fig.12 In addition, the fluorescence spectrum was normalized so that the maximum emission intensity was 1. The fluorescence spectrum of Example 1 can be regarded as Ce 3+ 5D 1 →4f 1 The broad spectrum caused by the transition can be regarded as the Cr 3+ The broad spectrum is formed due to the dd transition of the ions. The peak wavelengths of the spectra are 558nm and 710nm.

[0178] according to Fig.12 It can be seen that the fluorescence spectrum of Example 1 is a fluorescence spectrum with less deep red light components that become noise of the near-infrared light image sensor than in the past. This is believed to be because the Cr 3+ The activated phosphor strongly absorbs Ce 3+ The deep red light component of the fluorescent component of the activated phosphor. In addition, it is not known that such an effect can actually be achieved, and it can only be confirmed through experimental verification.

[0179] In addition, the ratio of the minimum luminous intensity to the maximum luminous intensity in the wavelength range of 550nm to 700nm of the fluorescence spectrum of Example 1 is 39%. This means that the wavelength converter of Example 1 receives blue light and emits fluorescence with a ratio of the minimum luminous intensity to the maximum luminous intensity of 40% or less in the wavelength range of 550nm to 700nm.

[0180] The fluorescence spectrum of Example 2 is shown in Fig.13 In addition, the fluorescence spectrum was normalized so that the maximum emission intensity was 1. The fluorescence spectrum of Example 2 can be regarded as Ce 3+ 5D 1 →4f 1The broad spectrum caused by the transition can be regarded as the Cr 3+ The broad spectrum is formed due to the dd transition of the ions. The peak wavelengths of the spectra are 517nm and 750nm.

[0181] according to Fig.13 It can be seen that the fluorescence spectrum of Example 2 is a fluorescence spectrum with less deep red light components that become noise of the near-infrared light image sensor than in the past. This is believed to be because: 3+ The activated phosphor strongly absorbs Ce 3+ The deep red light component of the fluorescent component of the activated phosphor. In addition, it is not known that such an effect can actually be achieved, and it can only be confirmed through experimental verification.

[0182] In addition, the ratio of the minimum luminous intensity to the maximum luminous intensity in the wavelength range of 550nm to 700nm of the fluorescence spectrum of Example 2 is 4%. This means that the wavelength converter of Example 2 receives blue light and emits fluorescence with a ratio of the minimum luminous intensity to the maximum luminous intensity of 40% or less in the wavelength range of 550nm to 700nm.

[0183] The entire contents of Tokugan 2019-082925 (filing date: April 24, 2019) are incorporated herein by reference.

[0184] As mentioned above, although the content of this embodiment is described based on an Example, it is obvious to a person skilled in the art that this embodiment is not limited to these description contents, and various deformation|transformation and improvement are possible.

[0185] Industrial Applicability

[0186] According to the present application, a wavelength converter that can fully separate the fluorescent components of visible light and near-infrared light and emit a fluorescence spectrum with relatively low luminous intensity of deep red light, as well as a light-emitting device, medical system, electronic equipment and inspection method using the wavelength converter can be provided.

[0187] Explanation of symbols

[0188] 1 Wavelength converter

[0189] 2. First phosphor

[0190] 3 Second phosphor

[0191] 5 Light Source

[0192] 10 Lighting device

[0193] 11 Endoscope (medical system)

[0194] 101 Endoscopic system (medical system)

[0195] 114V Visible light image sensor (first image sensor)

[0196] 114IR IR light image sensor (second image sensor)

Claims

1. A wavelength converter comprising a first phosphor and a second phosphor, The first phosphor is Cr 3+ activation, The second phosphor is Ce 3+ and Eu 2+ At least one of the ions in the in, The fluorescence spectrum of the fluorescence emitted by the second phosphor has a peak with a maximum fluorescence intensity in a wavelength range of 500 nm to less than 580 nm. The wavelength converter emits fluorescence having light components in the entire wavelength range of 500 nm to less than 580 nm. And emit light of a spectrum in which the ratio of the minimum luminous intensity to the maximum luminous intensity is less than 40% within the wavelength range of 550nm to 700nm, The wavelength having the highest luminous intensity is greater than or equal to 550 nm and less than 580 nm, and the wavelength having the lowest luminous intensity is between 580 nm and 700 nm.

2. The wavelength converter according to claim 1, wherein: The fluorescence spectrum of the fluorescence emitted by the first phosphor has a peak where the fluorescence intensity shows a maximum value in a wavelength region of 710 nm or longer.

3. The wavelength converter according to claim 1 or 2, wherein: The second phosphor is Ce 3+ Activated phosphor. 4 . A light emitting device comprising the wavelength converter according to claim 1 and a light source, wherein the light source emits light having a wavelength converted by the wavelength converter.

5. The light emitting device according to claim 4, wherein: The light emitted by the light source is laser light.

6. The light emitting device according to claim 5, wherein: The spectrum of the light emitted by the light source has a peak showing a maximum intensity in a wavelength region of 420 nm to less than 480 nm, The light emitted by the light source is blue light.

7. The light emitting device according to claim 6, wherein: The light source includes a solid light emitting element, and the blue light is emitted by the solid light emitting element. The light emitting device according to claim 4 , which is a light source for a sensing system or a lighting system for a sensing system. 9 . A medical system comprising the light emitting device according to claim 4 .

10. The medical system of claim 9, which is used for any of fluorescence imaging or photodynamic therapy.

11. The medical system according to claim 9, further comprising a first image sensor and a second image sensor, The first image sensor detects the reflected light of the visible light component emitted by the light emitting device. The second image sensor detects the near-infrared fluorescent component emitted by the medicine. in, The medicine is excited by the light emitted by the light emitting device. 12 . An electronic device comprising the light emitting device according to claim 4 . 13 . The electronic device according to claim 12 , which is any one of an information recognition device, a discrimination device, a detection device or a testing device.

14. The electronic device according to claim 13, wherein: The inspection device is any of a medical inspection device, an agricultural and animal husbandry inspection device, a fishery inspection device or an industrial inspection device.

15. A testing method using the light emitting device according to any one of claims 4 to 8.

Images